Atomic chip for ultra-cold atom inertial sensors and associated sensors

Abstract

The invention relates to an atomic chip (Ach) for an ultracold atomic sensor, said chip comprising an XY plane perpendicular to a Z axis, said atomic chip comprising: - first and second coplanar waveguides (CPWX1, CPWX2) suitable for propagating microwaves at respective angular frequencies ω a and ω b , said waveguides being placed symmetrically on either side of the X axis and being referred to as X directors, - first and second coplanar waveguides (CPWY'1, CPWY'2) suitable for propagating microwaves at respective angular frequencies ω' a and ω' b , said waveguides being placed symmetrically on either side of an axis whose projection in the XY plane lies along an axis Y' different from the X axis and contained in the XY plane, the X directors being electrically insulated from the Y' directors, the intersection of said directors forming a parallelogram with a center O defining the origin of a reference frame XYZ, - at least a first wire (W1) and a second wire (W2), each of whose projections in the XY plane subtend O and form an angle between them greater than or equal to 20°, said wires being suitable for the passage of direct current.

Description

Technical Field

[0001] This invention relates to the field of ultracold atom inertial sensors. More specifically, this invention relates to chips that allow the measurement of angular velocities around two or three measurement axes, and associated sensors. Background Technology

[0002] The sensor described in document WO2017089489 is an on-chip ultracold atom inertial sensor (gyroscope) that uses captured matter waves to describe closed paths in enclosed regions. The structure and working principle of this sensor will be reviewed below.

[0003] Rotational measurements in this type of device are performed using the Sagnac effect. The phase shift θ between two matter waves rotating counter-clockwise in a reference frame rotating at an angular velocity Ω is given by the following equation:

[0004]

[0005] Where A is the area enclosed by the atomic path, and m is the mass of the atom. It is a simplified Planck constant.

[0006] Ultracold atoms are defined as atoms with temperatures below 400 nanokelvin, preferably below 300 nanokelvin. The temperatures of hot ultracold atoms, such as for rubidium atoms, are included between 50 and 400 nanokelvin, preferably between 100 and 300 nanokelvin.

[0007] The principle is to obtain a path that two counter-propagating magnetically trapped atomic clouds must traverse. The magnetic trap is formed and moved along the path via wires and a microwave guide, for example... Figure 1 The arrangement is shown.

[0008] Figure 1 The diagram schematically illustrates an ultracold atom chip 1, its ultracold atoms 12, and the paths 16 of two atomic clouds N1 and N2. A portion of the surface of chip 1 forms a measurement plane 13. An axis perpendicular to the measurement plane 13 defines a measurement axis Z, around which a gyroscope measures rotation Ωz.

[0009] Chip 1 includes means for generating a first ultracold atom cage T1 and a second ultracold atom cage T2, the cages allowing an ultracold atom cloud 12 to be fixed at a predetermined distance h from the measuring plane 13 in an internal state different from the other cage. For example, cage T1 includes atoms in electronic state |a> (cloud N1), while cage T2 includes atoms in state |b> (cloud N2). States |a> and |b> are separated by a frequency ω0 / 2π. For example, in the case of rubidium 87, these are two hyperfine states |F = 1, m- F =-1> and |F=2,m- F =1> The problem is that they are about 6.8 GHz apart.

[0010] These devices also allow the cloud to move along path 16, which lies in a plane parallel to the measuring plane 13 at a height of h above the plane, such as... Figure 1 As shown in the diagram. These devices include waveguides and wires as described below.

[0011] The device includes components suitable for use at an angular frequency ω. a and ω b A first waveguide CPW1 and a second waveguide CPW2 propagate microwaves. The waveguides are parallel and symmetrically placed with respect to the Y-axis of the measurement plane. Both waveguides CPW1 and CPW2 are connected to at least one generator of voltage or current at the microwave frequency. For example, each waveguide is generated by depositing three parallel wires to form a coplanar waveguide. In other embodiments, other types of waveguides can be used, particularly those whose production is compatible with microfabrication techniques employing deposition or etching. For example, microstrip lines can be produced.

[0012] The device also includes wires integrated into chip 1 that can carry DC current. The wires are categorized as wires WIz along a symmetry axis Y perpendicular to X and contained within the measurement plane 13, and multiple n wires WIdi, with indices i varying from 1 to n, which are parallel to each other and parallel to the X-axis, where n is at least equal to 2. Figure 1 In the example, n = 3, meaning there are 3 wires WId1, WId2, and WId3. The wires are arranged to define n intersection points Ci (intersections between WIz and WIdi) on the Y-axis, which are 3 intersection points C1, C2, and C3 in this case.

[0013] Each wire is connected to one or more current and / or voltage generators, which are themselves connected to a processing unit including at least one microprocessor. The voltage and / or current generators allow direct current and alternating current to be driven through the wires. In particular, direct current is driven through the wires.

[0014] In the sensor, an atom chip 1 is placed in a vacuum chamber, which is maintained by, for example, an ion pump and preferably includes magnetic shielding. The vacuum chamber includes an ultracold atom source. An ultracold atom source is defined as:

[0015] - Atom distributors, such as those implemented by heating filaments that generate rubidium vapor;

[0016] - Primary (optical and / or magnetic) atom cages allow for the precooling and placement of ultracold atom clouds near the chip so that atoms can be loaded into magnetic cages T1 and T2 as described below.

[0017] The vacuum chamber also includes a magnetic field source located outside the chip 1. This allows for the generation of a uniform static magnetic field 20 over a thickness at least on the order of height h above the measurement plane 13. Advantageously, the direction of the uniform magnetic field is parallel to the measurement plane.

[0018] exist Figure 1 In the diagram, path 16 (dashed line) illustrates the path of the ultracold atom cloud 12. This closed path defines a region denoted as A. Distance h separates the plane of path 16 from the measurement plane 13 of the chip. Preferably, h is included between 500 nm and 1 mm, and more preferably between 5 μm and 500 μm.

[0019] Figure 2 The diagram illustrates the guides and wires of the atomic chip, as well as the geometry of cages T1 and T2.

[0020] The specific arrangement of the wires and waveguides, along with the uniform magnetic field of the source, makes it easy to obtain two cages, T1 and T2, such as... Figure 2 Part a) is shown. Each cage T1 and T2 having the same non-zero minimum value V0 and the same curvature is a necessary condition for sensor operation. Specifically, as described below, when a DC current is applied to at least two wires at the intersection, the minimum value of the resulting potential well is perpendicular to that intersection. Then, when microwave power is transmitted through the waveguide, this central well is converted into two wells located on either side of the initial well in the waveguide direction. If the initial well is not strictly equidistant from the two waveguides, the two potential wells created will not have strictly identical minimum values ​​V0 and the same curvature.

[0021] Figure 2 Part c) shows the layout of the wires and waveguides (viewed from above) that define the initial cross point C1. Figure 2Section b) illustrates the corresponding layout of the wires and waveguides printed on the chip (as seen in the cross-sectional profile), with the cross-section passing through wire WId1, which intersects wire WIz along the axis of symmetry Y. Waveguides CPW1 and CPW2 are coplanar waveguides located on the first layer N1. Insulating layer 18 advantageously allows the measurement plane to be flattened. The material of the electrically insulating layer can be, for example, silicon dioxide, silicon nitride, or benzocyclobutene. A conductive material, such as gold, is used to fabricate the wires and deposited on substrate 15 to form the second layer N2. The substrate can be made of, for example, silicon, aluminum nitride, or silicon carbide.

[0022] a) Partially shows the symmetric separation of the ultracold atoms, which is specific to the internal state of the ultracold atoms, and more precisely to the change in potential as a function of the position on the X-axis of chip 1.

[0023] The curve “a” drawn in black represents a potential well, which corresponds to the relationship between a uniform magnetic field and the field generated by two secant wires—the current I. Z The wire WIz passes through the current Id1, and the wire WId1 passes through the current Id1. A local potential well is generated, forming a three-dimensional atomic cage T. An ultracold atomic cloud may be trapped inside and cooled.

[0024] The curve "b" drawn with a light gray dashed line schematically illustrates the frequency ω. b The potential generated by microwaves transmitted through waveguide CPW1. Frequency ω b Microwaves, through the emitted field, allow the energy of ultracold atoms to be altered, and atoms in the internal state |b> are moved. Curve “e”, drawn as a light gray solid line, illustrates the potential observed in the internal state |b>, a result of the contributions of curves “a” and “b” to the final potential. Curve “e” has a local potential minimum, allowing the ultracold atom cloud in the internal state |b> to be locally trapped.

[0025] Similarly, the curve "d" drawn with a dark gray dashed line schematically illustrates the frequency ω. a The potential generated by microwaves transmitted through waveguide CPW2. The frequency is ω. a Microwaves, through the emitted field, allow the energy of ultracold atoms to be altered, and atoms in the internal state |a> are moved. Curve "c," drawn with a dark gray solid line, illustrates the potential seen by the atoms in the internal state |a>, a result of the contributions shown by curves "a" and "d" to the final potential. Curve "c" has a local energy minimum, allowing the ultracold atom cloud in the internal state |a> to be locally trapped.

[0026] An ultracold atomic cloud with internal states |a> and |b> can be made to simultaneously have a frequency of ω a The wave propagates through CPW2 and has a frequency of ω. bThe wave propagates through CPW1 and is symmetrically separated and captured about the axis of symmetry Y. In order to obtain two traps (with the same minimum value V0 and the same curvature value), it is important to place the intersection point C1 at an equal distance from CPW1 and CPW2, i.e. on the axis of symmetry Y.

[0027] Figure 3 The principle behind the generation of path 16 is explained. Figure 3 Part a) schematically shows the motion sequence of each ultracold atom cloud at characteristic times t1 to t9. Part b) supplementarily illustrates the sequence of various currents applied to the conductor, the power applied to the waveguide, and the frequency applied to the waveguide at the times corresponding to those in part a).

[0028] exist Figure 3 In the sequence shown, the current I flowing through WIz z (Not shown) Remains at a constant value. In section b), the values ​​of current, power, and frequency are arbitrary. The y-axis, labeled δ frequency, corresponds to the frequency variation with respect to the average frequency value, expressed in arbitrary units. When using rubidium atoms, the current through the wire can be included between 100 μA and 10 A, and the angular frequency injected into the waveguide can be included between 6.6 GHz and 7 GHz.

[0029] In step A0, atoms are prepared. An ultracold atomic cloud 12 is generated, which includes the following stages: distributing the atoms at a distance h from the measurement plane, cooling the atoms, initializing the atoms to at least one internal state |a>, and trapping the ultracold atomic cloud in a local potential well (cage T). Figure 2 The curve “a” in part a) shows a height h that is not 0 because the uniform magnetic field 20 is not zero. Capture is achieved by passing a direct current through wire WIz and then through one of several wires, WIdi, whose intersection defines the starting point (here, C1 and WId1). Simultaneously, a bias magnetic field 20 is applied parallel to the plane of the atomic chip, superimposed on the magnetic field generated by the first two wires. The atomic cloud is then captured perpendicularly to C1, the intersection of wires WIz and WId1.

[0030] In step B0, the internal state is initialized by coherently superimposing the ultracold atoms between states |a> and |b> via a first / 2 pulse. This pulse can be generated by a laser, a microwave transmitter, or more generally by emitting waves at a suitable transition frequency. Current I Z and I d1 The two internal states, |a> and |b>, are applied to wires WIz and WId1, respectively. They coherently overlap and are spatially perpendicular to the intersection point C1.

[0031] Then the wave function is:

[0032]

[0033] In step C0, the atomic cloud of the inner state |a> in cage T1 is spatially separated from the atomic cloud of the inner state |b> in cage T2, and the cages move in opposite directions along a closed path 16 contained in a plane perpendicular to the measurement axis Z. The atomic cloud of the inner state |a> is represented by a disk with a bright texture, and the atomic cloud of the inner state |b> is represented by a disk with a darker texture. This step runs from t1 to t9.

[0034] Between t1 and t2, the microwave power injected into waveguides CPW1 and CPW2 gradually changes from 0 to its maximum value. Angular frequency ω a It is sent to waveguide CPW1, and the angular frequency ω b The cloud is sent to waveguide CPW2, which allows two clouds with different internal states to move a distance d on either side of the symmetry axis Y, to a position schematically shown as t2. The aforementioned ultracold atom cage T at time t1 is thus transformed into two ultracold atom cages T1 and T2, each cage allowing an ultracold atom cloud with an internal state different from the other cage to be fixed (in this example, internal state |a> is in one cage (e.g., T1), while internal state |b> is in the other cage T2, as shown below). Figure 2 As shown in part a) of ).

[0035] The intersection point Ci corresponds to the intersection of conductor WIz and conductor WIdi.

[0036] Between t2 and t3, the current I d1 Gradually cut off, I d2 Gradually increase to its maximum value (the time interval between t2 and t3 is typically on the order of 10 ms and can be included between 0.1 ms and 100 ms): the two cages T1 and T2 move to the right to the position schematically shown for t3.

[0037] Between t3 and t4, the current I d2 Gradually decrease, I d3 Gradually increase to its maximum value: the two traps move to the right to the position schematically shown in t4.

[0038] Between t4 and t5, the microwave power gradually decreases: the two cages are brought back to the same position on the chip, as schematically shown at t5.

[0039] At t5, the angular frequencies of the two microwave waveguides are modified: angular frequency ω b Applied to CPW1, angular frequency ω a Applied to CPW2.

[0040] Between t5 and t6, the power in the two waveguides gradually changes from 0 to its maximum value: the cages separate in the vertical direction, as schematically shown at t6 in the figure.

[0041] Between t6 and t7, the current I d3 Gradually cut off, I d2 Gradually increase to its maximum value: move the two cages T1 and T2 to the left to the position schematically shown at t7.

[0042] Between t7 and t8, the current I d2 Gradually decrease, I d1 Gradually increase to its maximum value: move both cages to the left to the position schematically shown at t8. This operation can be repeated multiple times with the other first conductors to increase the area enclosed by path 16.

[0043] Between t8 and t9, the microwave power in the waveguide gradually decreases. The two cages, T1 and T2, move until they merge into a single cage located at the schematic starting point t1.

[0044] DC current is thus applied to the two wires corresponding to the initial crossover point C1, and over time these currents are continuously applied to the respective crossover points Ci located on the axis of symmetry, while microwave power is applied to the waveguide.

[0045] During step C0, the DC current applied to the various conductors WIdi is at 0 and at its maximum value Idimax (in Figure 3 The values ​​of 1 and 20 (normalized to 1) change continuously (increase and decrease), while the magnetic field 20 and current I... z The height remains constant throughout the sequence. Throughout sequences A0, B0, and C0, the two cages T1 and T2 remain at height h.

[0046] The two cages, T1 and T2, move in the direction of the "open" intersection: from intersection C1 to intersection Cn. The return journey is achieved by reversing the microwave frequency and continuously opening a DC current in the wires corresponding to each intersection Cn to C1.

[0047] Therefore, the cage travels in closed path 16.

[0048] The closed path 16 of the atom contains area A, therefore the atomic wavefunction is:

[0049]

[0050] in:

[0051]

[0052] In step D0, the internal states |a> and |b> are recombinated by applying a second π / 2 pulse to the ultracold atom, which transfers the phase difference to the population of the two atomic states:

[0053]

[0054]

[0055] Where ω is the angular frequency of the π / 2 pulse.

[0056] π / 2 pulses can be sent to atoms via a microwave guide or through a separate microwave transmitter.

[0057] Next, the density of atoms selected from at least |a> and |b> internal states is measured. This measurement can be performed, for example, by using laser absorption to detect the resonance between the angular frequency specific to the internal state and the angular frequency of the laser.

[0058] Finally, in step E0, the Sagnac phase shift of the ultracold atoms is determined, and the rotational speed of the sensor about the Z-axis is calculated.

[0059] Measurements of at least one atomic population in one of states |a> or |b> allow for the determination of the Sagnac phase shift, for example, for the internal state |a>, using equation (5), and then using equation (1) to determine the rotational velocity Ω. z .

[0060] Before measuring the Sagnac phase shift, the cage can be made to travel along this path N times, thus allowing the measurement of a phase shift that may be N times larger.

[0061] To implement the above method, the rotational speed Ω can be measured. z Ultracold atom sensors include:

[0062] -As described above, the atomic chip 1 has waveguides and wires.

[0063] - An atomic source used to generate ultracold atomic clouds near the measurement plane 13 of an atomic chip.

[0064] - Uniform magnetic field generator 20

[0065] - At least one processor, at least one DC current or voltage generator suitable for controlling the current in the conductor, and at least one microwave current or voltage generator connected to the waveguide.

[0066] - A system for detecting light intensity, suitable for measuring at least one population of ultracold atoms in an internal state, which allows for the determination of the Sagnac phase shift and rotational velocity Ω. z .

[0067] The sensors described above and in document WO2017089489 allow for the measurement of rotational speed only about the Z-axis perpendicular to the chip plane, based on a path contained in a plane parallel to the measurement plane 13. To be able to measure rotational speeds about three axes, three sensors of this type are required, which is expensive, space-consuming, and complex to operate, especially regarding the corresponding positions of the three axes (the adjustment of their orthogonality), which exhibits drift over time, reducing assembly accuracy.

[0068] One object of the present invention is to overcome the above-mentioned disadvantages by providing an atomic chip and a sensor based on the chip, wherein in a first version of the sensor the sensor is capable of measuring rotational speed about two vertical axes, and in a second version the sensor the sensor is capable of measuring rotational speed about three vertical axes. Summary of the Invention

[0069] One aspect of the present invention is an atomic chip for an ultracold atom sensor, the chip comprising an XY plane perpendicular to the Z-axis, the atomic chip comprising:

[0070] - First and second coplanar waveguides, suitable for operation at their respective angular frequencies ω a and ω b Microwaves are propagated by waveguides that are symmetrically positioned on either side of the X-axis and are referred to as X-direction guides.

[0071] - First and second coplanar waveguides, suitable for operating at their respective angular frequencies ω' a and ω' b Microwaves are propagated by waveguides symmetrically positioned on either side of an axis and referred to as Y'-direction guides, the projection of which onto the XY plane follows an axis Y' that is different from the X-axis and contained within the XY plane.

[0072] The X-direction guide and the Y'-direction guide are electrically insulated, and the intersection of the guides forms a parallelogram with center O, which defines the origin of the reference system XYZ.

[0073] - At least a first conductor and a second conductor, whose respective projections in the XY plane intersect O and form an angle greater than or equal to 20° between them, said conductors being suitable for the passage of direct current.

[0074] According to one embodiment, the X-direction guide, the Y-direction guide, the first wire, and the second wire are respectively placed on different layers, each layer being electrically insulated from the adjacent layer, and the layers forming a stack placed on a substrate.

[0075] According to one embodiment, the projection of the first conductor in the XY plane is oriented along the X-axis, and the projection of the second conductor in the XY plane is oriented along the Y'-axis.

[0076] According to one embodiment, the Y' axis coincides with the Y axis. According to another embodiment, the Y' axis coincides with the Y axis, and the projections of the first conductor and the second conductor on the XY plane are mutually perpendicular and oriented at 45° to the X-axis and Y-axis, respectively.

[0077] According to one variant, the atomic chip further includes: a plurality of wires placed parallel to the first wire to form a first plurality of wires, and a plurality of wires placed parallel to the second wire to form a second plurality of wires, wherein the projections of the wires in the first plurality of wires and the second plurality of wires in the XY plane define intersection points in the XY plane.

[0078] The first plurality of wires and the second plurality of wires are arranged such that at least one set of intersections are located within the parallelogram.

[0079] Preferably, the first plurality of wires and the second plurality of wires are configured such that a subset of the set of intersections lies on the X-axis, and another subset of the set of intersections lies on the Y'-axis.

[0080] According to one embodiment, the conductor has a width, and the distance between two adjacent conductors is included between 0.5 times and 2 times the width.

[0081] According to one variant, the atomic chip according to the invention is a matrix array atomic chip, and in a first embodiment, it includes a first group of first wires with index n and a second group of second wires with index m, which are perpendicular to each other and respectively form rows and columns of a matrix array.

[0082] Each of the first wire with index n and the second wire with index m coincides with the axis Xn with index n and the axis Ym with index m, respectively. The guide along the Xn axis is therefore common to all pixels in row n, and the guide along the Ym axis is therefore common to all pixels in column m. Each pixel of the matrix array forms a basic chip.

[0083] According to one variant, the atomic chip according to the invention is a matrix array atomic chip, and in a second embodiment, it includes a first group of first wires with index n and a second group of second wires with index m, which are perpendicular to each other and respectively form rows and columns of a matrix array.

[0084] Each of the first conductor with index n and the second conductor with index m is oriented at 45° to the axis Xk with index k and at 45° to the axis Y1 with index l, respectively. The guide along the Xk axis is therefore common to all pixels on the first diagonal of the matrix array, and the guide along the Y1 axis is therefore common to all pixels on the second diagonal. Each pixel of the matrix array forms a basic chip.

[0085] According to one embodiment, at least one conductor in the first group or the second group is replaced by a plurality of parallel conductors, a portion of which is included in an associated parallelogram.

[0086] The present invention also relates to an ultracold atom sensor that allows for the measurement of rotational speeds about at least two axes X and Y', comprising:

[0087] -An atomic chip according to the invention placed in a vacuum chamber,

[0088] - An atomic source arranged to generate an ultracold atomic cloud near the XY plane of the atomic chip.

[0089] The ultracold atoms have a superposition of internal states |a> and |b> during the initialization phase implemented by the sensor.

[0090] - Uniform magnetic field generator

[0091] - At least one processor, at least one DC current or voltage generator suitable for controlling the current in the conductor, and at least one microwave current or voltage generator connected to the waveguide.

[0092] - During the implementation of the sensor, the waveguide, the wire, and, where appropriate, the magnetic field are configured as follows:

[0093] - Modifying the energy of the ultracold atoms to create potential wells for ultracold atoms in internal state |a> and internal state |b>, thereby forming a first ultracold atom cage and a second ultracold atom cage, one cage enabling the ultracold atom cloud to be fixed in an internal state different from the other cage at a controlled distance from the measurement plane, and

[0094] - Spatially separate two cages and move the cages at least along a first closed path contained in a plane perpendicular to X and a second closed path contained in a plane perpendicular to Y', each path being traveled in one direction by ultracold atoms of the first cage and in the opposite direction by ultracold atoms of the second cage.

[0095] The sensor also includes a system for detecting light intensity, which is suitable for measuring at least one population of the ultracold atoms in the internal state.

[0096] According to one embodiment, the waveguide and the at least one microwave current or voltage generator, the wire and the at least one DC current or voltage generator, and the uniform magnetic field generator are configured such that the first closed path and the second closed path each include at least a first portion located at a first height above the XY plane and a second portion located at a second height, the second height being significantly greater than the first height, in order to induce a transfer from the first height to the second height in such a way as follows:

[0097] - at the first non-zero value (I W1 ', I W2 ') and the second non-zero value (I W1 “I” W2 The increase in the DC current value through each conductor between () and / or,

[0098] - The decrease in the uniform magnetic field value between the first non-zero value (B0') and the second non-zero value (B0”),

[0099] And the transfer from the second altitude to the first altitude and vice versa.

[0100] According to one variant, the ultracold atom sensor allows for the measurement of rotational speeds about three axes: X, Y', and Z, including:

[0101] -An atomic chip according to the invention placed in a vacuum chamber,

[0102] - An atomic source is arranged to generate an ultracold atomic cloud near the XY plane of the atomic chip, the ultracold atoms having a superposition of internal states |a> and |b> in an initialized state.

[0103] - Uniform magnetic field generator

[0104] - At least one processor, at least one DC current or voltage generator suitable for controlling the current in the conductor, and at least one microwave current or voltage generator connected to the waveguide.

[0105] -The waveguide and the wire are configured as follows:

[0106] - Modifying the energy of the ultracold atoms to create potential wells for ultracold atoms in internal state |a> and internal state |b>, thereby forming a first ultracold atom cage and a second ultracold atom cage, one cage enabling the ultracold atom cloud to be fixed in an internal state different from the other cage at a controlled distance from the measurement plane, and

[0107] - The cages are spatially separated into two cages and moved along a first closed path contained in a plane perpendicular to X and initialized from a first initialization intersection point located on the X-axis, a second closed path contained in a plane perpendicular to Y' and initialized from a second initialization intersection point located on the Y'-axis, and a third closed path contained in a plane perpendicular to Z and initialized from a third initialization intersection point located at point O. Each path is traveled in one direction by ultracold atoms from the first cage and in the opposite direction by ultracold atoms from the second cage.

[0108] The sensor also includes a system for detecting light intensity, which is suitable for measuring at least one population of the ultracold atoms in the internal state.

[0109] According to one embodiment, the waveguide and at least one microwave current or voltage generator, the wire and at least one DC current or voltage generator, and the uniform magnetic field generator are configured such that each of the first and second closed paths includes at least a first portion located at a first height (h1) above the XY plane and a second portion located at a second height (h2), the second height (h2) being substantially greater than the first height, and causing a transfer from the first height to the second height via:

[0110] - Between the first and second non-zero values, by defining the increase of the DC current value of each wire at the associated initial crossover point, and / or,

[0111] - The decrease in the value of the uniform magnetic field between the first and second non-zero values

[0112] The transfer from the second altitude to the first altitude and vice versa.

[0113] According to one variant, the ultracold atom sensor includes:

[0114] -According to the matrix array atomic chip of the present invention,

[0115] - An atomic source arranged to generate an ultracold atomic cloud near the XY plane of the atomic chip.

[0116] - Uniform magnetic field generator

[0117] - At least one processor, at least one DC current or voltage generator suitable for controlling the current in the conductor, and at least one microwave current or voltage generator connected to the waveguide.

[0118] - A system for detecting light intensity

[0119] The sensor is suitable for measuring, as needed, at least one acceleration and / or rotational speed along / around at least one direction corresponding to axis Xn and / or axis Ym in a reconfigurable manner using the base chip.

[0120] According to another aspect, the present invention relates to a method for measuring rotational speeds about two axes X and Y' using an ultracold atom sensor comprising an atom chip, the atom chip being placed in a vacuum chamber and comprising an XY plane perpendicular to the Z-axis, the atom chip comprising:

[0121] - First and second waveguides, adapted to operate at their respective angular frequencies ω a and ω b Microwaves are propagated by waveguides that are symmetrically positioned on either side of the X-axis and are referred to as X-direction guides.

[0122] - First and second waveguides, adapted to operate at their respective angular frequencies ω' a and ω' b Microwaves are propagated by waveguides symmetrically placed on either side of the axis and referred to as Y' direction guides, the projection of the axis onto the XY plane along the axis Y' contained in the XY plane.

[0123] The X-direction guide is electrically insulated from the Y'-direction guide, and the intersection of the guides forms a parallelogram with center O. Center O defines the origin of the reference system XYZ.

[0124] At least a first conductor W1 and a second conductor W2, whose respective projections in the XY plane secant the point O and form an angle greater than or equal to 20° between them, are suitable for carrying direct current.

[0125] To measure the rotational speed about one of axes X and Y' (this axis is referred to as the measurement axis), the method includes the following steps:

[0126] A generates the ultracold atom cloud, which includes the following stages: distributing the atoms at a first height above the XY plane, cooling the atoms, initializing the atoms to at least one internal state |a>, and trapping the ultracold atom cloud in a local potential well, the trapping being performed by passing a DC current through first and second wires.

[0127] B initializes the internal state by coherently superimposing the ultracold atoms between states |a> and |b> via a first π / 2 pulse;

[0128] C spatially separates the atomic cloud of the internal state |a> in one cage from the atomic cloud of the internal state |b> in another cage, and moves the cages in opposite directions along a closed path contained in a plane perpendicular to the measurement axis and initialized from point O by: applying a voltage or current of a predetermined microwave frequency to the first and second guides along the measurement axis in a predetermined sequence; applying at least two different DC current or voltage values ​​to the first and second conductors; and / or applying at least two different values ​​of a uniform magnetic field, the path including a portion located at a second height from the XY plane that is different from the first height.

[0129] D reassembles the internal states |a> and |b> by applying a second π / 2 pulse to the ultracold atoms and then measuring the density of atoms in internal states selected from at least |a> and |b>.

[0130] E determines the Sagnac phase shift of the ultracold atom and calculates the rotational speed of the sensor about the measurement axis.

[0131] The method also includes performing steps A through E to measure the rotational speed about another measuring axis.

[0132] According to one variant, the method according to the invention uses a cold atom sensor comprising an atom chip to measure rotational speeds about three axes X, Y', and Z, said atom chip being placed in a vacuum chamber and comprising an XY plane perpendicular to the Z-axis, the axes XYZ forming an orthogonal reference system, said atom chip comprising:

[0133] - First and second waveguides, adapted to operate at their respective angular frequencies ω a and ω b Microwaves are propagated by waveguides that are symmetrically positioned on either side of the X-axis and are referred to as X-direction guides.

[0134] - First and second waveguides, adapted to operate at their respective angular frequencies ω' a and ω' b Microwaves are propagated by waveguides symmetrically positioned on either side of an axis and referred to as Y'-direction guides, whose projection in the XY plane follows the axis Y' contained in the XY plane.

[0135] The X-direction guide and the Y'-direction guide are electrically insulated, and the intersection of the guides forms a parallelogram with center O. Center O defines the origin of the reference system XYZ.

[0136] - A first plurality of parallel conductors and a second plurality of parallel conductors, the projections of the conductors in the first plurality of conductors and the conductors in the second plurality of conductors in the XY plane defining the intersection point.

[0137] The projections of the plurality of conductors in the XY plane form an angle greater than or equal to 20° between them. The projections of the conductors in the first plurality of conductors and the conductors in the second plurality of conductors in the XY plane intersect at point O. The first plurality of conductors and the second plurality of conductors are arranged such that at least one set of intersection points lies within the parallelogram.

[0138] The method includes:

[0139] - Perform steps A to E as described above to measure the rotational speed about X, wherein the first closed path contained in the plane perpendicular to X is initialized from the first initialization intersection point located on the X-axis.

[0140] - Perform steps A to E as described above to measure the rotational speed around Y', wherein the second closed path contained in the plane perpendicular to Y' is initialized from the second initialization intersection point located on the Y' axis, and

[0141] - Measure the rotational speed about the Z-axis, corresponding to the measurement axis:

[0142] - Implement steps A and B, as described above.

[0143] Step C' includes spatially separating the atomic cloud of the internal state |a> in one cage from the atomic cloud of the internal state |b> in another cage, and moving the cages in opposite directions along a closed path initialized from a third initialization intersection point in a plane perpendicular to the Z-axis by applying a voltage or current of a predetermined microwave frequency to one of the first and second guides in a predetermined sequence along one of the axes X and Y', referred to as the selection axis, and applying a DC current or voltage to the conductors in the first plurality of conductors and the second plurality of conductors, thereby sequentially stimulating the intersection point placed on or near the selection axis.

[0144] - Implement steps D and E.

[0145] The following description presents several exemplary embodiments of the device of the present invention: these examples do not limit the scope of the invention. These exemplary embodiments not only include the basic features of the invention, but also include additional features related to the embodiments discussed. Attached Figure Description

[0146] The invention will be better understood from the following detailed description given with reference to the accompanying drawings, which are given by way of non-limiting example and in which:

[0147] [ Figure 1 ] Figure 1(Cited) illustrates an example of the topology of the wire and microwave guide, as well as the paths of the two atomic clouds.

[0148] [ Figure 2 ] Figure 2 (Cited) illustrates the guides and wires of the atomic chip, as well as the geometry of cages T1 and T2.

[0149] [ Figure 3 ] Figure 3 (Already cited) Explains the principle of generating atomic cloud paths on an atomic chip.

[0150] [ Figure 4 ] Figure 4 An atomic chip for an ultracold atom sensor according to a first aspect of the present invention is shown.

[0151] [ Figure 5 ] Figure 5 A cross-section of a preferred embodiment of an atomic chip passing through the OXZ plane along the Z-axis is shown.

[0152] [ Figure 6 ] Figure 6 The closed paths of two atomic clouds in a plane containing Z are shown using an atomic chip according to the invention.

[0153] [ Figure 7 ] Figure 7 A first variant of the arrangement of waveguides and conductors is shown, in which the projection of the first conductor W1 in the XY plane is oriented along the X-axis and the projection of the second conductor W2 in the XY plane is oriented along the Y'-axis.

[0154] [ Figure 8 ] Figure 8 The second variant is shown, in which the Y' axis coincides with the Y axis.

[0155] [ Figure 9 ] Figure 9 The combination of the first variant and the second variant is shown.

[0156] [ Figure 10 ] Figure 10 A third variant is shown, in which the Y' axis coincides with the Y axis, and the corresponding projections of the first and second conductors in the XY plane are perpendicular to each other and at 45° to the X and Y axes, respectively.

[0157] [ Figure 11 ] Figure 11 An ultracold atom sensor according to another aspect of the invention is shown, which allows for the measurement of rotational speeds about at least two axes, X and Y'.

[0158] [ Figure 12 ] Figure 12The example of path TX shows the route followed by which two atomic clouds form closed loops multiple times.

[0159] [ Figure 13 ] Figure 13 A timing diagram showing the values ​​of the current applied to the two conductors, the power and frequency applied to the microwave guide, and the uniform magnetic field B0 during the time interval between the first and last time points of the preceding time is presented.

[0160] [ Figure 14 ] Figure 14 An atomic chip compatible with measurements around / along three axes according to the present invention is shown, comprising a plurality of wires placed parallel to a first wire to form a first plurality of wires WPl, and a plurality of wires placed parallel to a second wire to form a second plurality of wires.

[0161] [ Figure 15 ] Figure 15 The path of two atomic clouds captured using X-direction guides (only those shown) is shown in a plane parallel to the plane of the atomic chip.

[0162] [ Figure 16 ] Figure 16 The timing diagram shows the associated current value applied to the conductor in question, the microwave power and frequency applied to the X-direction guide, and the uniform magnetic field as a function of time.

[0163] [ Figure 17 ] Figure 17 A first variant of a compatible 3-axis atom chip is shown, in which the Y' axis coincides with the Y axis and two multiple lines are each parallel to one axis.

[0164] [ Figure 18 ] Figure 18 A second variant of a compatible 3-axis atom chip is shown, in which the Y' axis coincides with the Y axis, and two multiple lines are perpendicular to each other and form an angle of 45° with the X and Y axes.

[0165] [ Figure 19 ] Figure 19 It shows Figure 18 A sub-variant of the variant, in which the generation of a uniform magnetic field, also known as a bias field, is integrated into an atomic chip by adding wires.

[0166] [ Figure 20 ] Figure 20 A first non-limiting example of using a first variant matrix array chip according to the invention to produce a measurement component is shown.

[0167] [ Figure 21 ] Figure 21 Another non-limiting example using a first variant matrix array chip is shown.

[0168] [ Figure 22 ] Figure 22 A first non-limiting example of using a second variant of a matrix array chip to generate a measurement component is shown.

[0169] [ Figure 23 ] Figure 23 Another non-limiting example using a second variant of the matrix array chip according to the invention is shown. Detailed Implementation

[0170] According to a first aspect, the present invention relates to an atomic chip Ach for ultracold atomic sensors, for example... Figure 4 As shown, the surface of the atomic chip defines an XY plane perpendicular to the Z-axis.

[0171] The atomic chip includes a first waveguide CPWX1 and a second waveguide CPWX2, which are coplanar and suitable for operation at their respective angular frequencies ω. a and ω b Microwaves are propagated by waveguides placed symmetrically on either side of the X-axis. These two guides are called X-direction guides.

[0172] The atomic chip also includes a first waveguide CPWY'1 and a second waveguide CPWY'2, which are coplanar and suitable for operation at their respective angular frequencies ω'. a and ω' b Microwaves are propagated by waveguides placed symmetrically on either side of an axis whose projection in the XY plane (perpendicular to the Z-axis) is along the axis Y' contained in the XY plane. These two guides are called Y'-direction guides.

[0173] The X-direction guide is electrically insulated from the Y'-direction guide. It is best to place them on separate layers (see [link]). Figure 5 Therefore, under the unrestricted assumption that the X-direction guide occupies the layer corresponding to the surface, the axis of symmetry of the two waveguides CPWY'1 and CPWY'2 lies in the plane of another layer, and thus it is indeed the projection of this axis of symmetry into the XY plane, called Y', located in the XY plane. Since the Y' axis is different from the X axis, the two sets of guides define an intersection point that forms a parallelogram at center O. This point O defines the origin of the reference frame XYZ. Below, for clarity, the geometric features of various elements of interest have been defined relative to the reference frame OXYZ. The XY plane is also called the horizontal plane.

[0174] The atomic chip Ach also includes at least a first conductor W1 and a second conductor W2 capable of carrying direct current. Furthermore, the projections of W1 and W2 onto the XY plane intersect at point O, and the angle between them is greater than or equal to 20°. For clarity, in all figures, the conductors and the waveguide in the Y' direction are shown in the XY plane.

[0175] Figure 5 A cross-section of a preferred embodiment of an atomic chip along the Z-axis through the OXZ plane is shown. Two conductors W1 and W2 can be on the same layer or electrically insulated from each other. In the latter case, the two conductors W1 and W2 then occupy two different layers, much like waveguides. Thus, according to one embodiment, X-direction waveguides CPWX1 and CPWX2, Y-direction guides CPWY'1 and CPWY'2, the first conductor W1, and the second conductor W2 are each placed on different layers, each electrically insulated from the adjacent layer: one N(CPW / X) layer for the X-direction guides, one N(CPW / Y') layer for the Y'-direction guides, one N(W1) layer for the first conductor, and one N(W2) layer for the second conductor. These four layers form a stack Emp placed on a substrate Sub. The waveguides and conductors are similar in nature to those described in document WO2017089489. Typically, the wires and conductors are made of gold or copper and insulated by layers of materials selected from AlN, SiO2, and Si3N4, which are deposited on a substrate Sub made of AlN, silicon, or SiO2 or SiC.

[0176] The atomic chip Ach differs from the chip described in document WO2017089489 in that it has four waveguides (instead of two), two wires, and a specific arrangement of these two wires relative to the four waveguides. The following will show how this primitive geometry can potentially generate two closed paths TX and TY' when the chip is integrated into an inertial sensor. These two closed paths TX and TY' are designed to travel by two clouds N1 and N2 of cold atom 12. These paths are not contained in a plane parallel to the XY plane, as described in the aforementioned document, but rather in two planes perpendicular to XY or perpendicular to X, where for TX, the YZ plane is perpendicular to X (e.g., ...). Figure 6 As shown in the figure, for TY', the XZ plane is perpendicular to Y'.

[0177] The generation of these two paths thus allows the sensors combined with the chip Ach to measure two rotational speeds Ωx and Ωy' relative to axes X and Y', respectively (see below).

[0178] Figures 7 to 10 Various variations of the waveguide and line arrangements are shown without limitation.

[0179] according to Figure 7 In the first variant shown, the projection of the first conductor W1 in the XY plane is oriented along the X-axis, and the projection of the second conductor W2 in the XY plane is oriented along the Y'-axis.

[0180] According to the second variant, the Y' axis coincides with the Y axis, such as... Figure 8As shown. The two guide components are then perpendicular to each other, which allows for the measurement of rotational speed about two mutually perpendicular axes, which is generally desirable.

[0181] Figure 9 The combination of the first variant and the second variant is shown.

[0182] according to Figure 10 The third variant shown has its Y' axis coinciding with the Y axis, and the corresponding projections of the first and second conductors in the XY plane are perpendicular to each other and oriented at 45° to the X and Y axes, respectively. This third variant has the advantage of allowing cage-specific axes to be oriented perpendicular to the guide.

[0183] According to another aspect, the present invention relates to an ultracold atom sensor 20, for example, as Figure 11 As shown, it allows for the measurement of rotational speeds around at least two axes, X and Y'.

[0184] The sensor comprises an atomic chip Ach, as described above, placed in a vacuum chamber, and an atomic source S arranged to generate an ultracold atomic cloud 12 near the XY plane of the atomic chip Ach. During the initialization phase of the sensor implementation, the ultracold atoms have a superposition of internal states |a> and |b>.

[0185] Sensor 20 also includes: a uniform magnetic field B0 generator GB, preferably parallel to the plane of the chip; at least one processor UT; at least one DC current or voltage generator GDC adapted to control the current in the conductors; and at least one microwave current or voltage generator GMW connected to the waveguide. Typically, all four guides may have one generator GMW, or two generators (one per pair of guides), or four generators (one per guide). The X- and Y' waveguides, conductors W1 and W2, and the magnetic field, where appropriate, are configured to perform the following steps during sensor implementation:

[0186] First, the energy of the ultracold atoms is modified to create potential wells for the ultracold atoms in the internal state |a> and for the ultracold atoms in the internal state |b>, thereby forming a first ultracold atom cage T1 and a second ultracold atom cage T2. One cage allows the ultracold atom cloud 12 to be fixed in an internal state different from the other cage at a controlled distance from the measurement plane (same as steps A0 and B0 above).

[0187] Next, the two cages T1 and T2 are spatially separated and move along a first closed path TX contained in a plane perpendicular to X and a second closed path TY' contained in a plane perpendicular to Y'.

[0188] Each path is formed by the ultracold atoms of the first cage traveling in one direction and by the ultracold atoms of the second cage traveling in the opposite direction.

[0189] The sensor also includes the SDET system for detecting light intensity, which is suitable for measuring at least one population of ultracold atoms in one of their internal states.

[0190] To measure the rotational velocity Ωx about the X-axis, the path TX is generated via a waveguide, a wire, and a field B0. Similarly, to measure the rotational velocity Ωy' about the Y'-axis, the path TY' is generated via a waveguide, a wire, and a field B0.

[0191] The cages separate in the same way as in document WO2017089489, but the paths followed by the clouds N1 and N2 of atoms subsequently trapped in cages T1 and T2, respectively, are different. Here, it is no longer a problem of describing paths in a horizontal plane, but rather a problem of describing paths in a vertical plane, as described above. The inventors have developed a method to achieve this path by modifying the height at which the clouds are trapped.

[0192] Figure 12 The illustration shows the path followed by two atomic clouds N1 and N2 forming a closed loop at multiple times t0 to t6 in an example of path TX. For clarity, only the waveguides CPWX1 and CPWX2 used to generate path TX are shown. For each time, the upper half of the associated plot represents the positions of the two clouds in the XY plane, and the lower half represents their positions in the cross-sectional view.

[0193] Figure 13 The time series diagram illustrates the current applied to the two conductors, the power and frequency applied to the microwave guide, and the value of the uniform magnetic field B0 during the time period between t0 and t6.

[0194] Initially at t0, a current Iw1 with value Iw1' is applied to wire W1, and a current Iw1 with value Iw2' is applied to wire W2, with no microwave power applied. The magnetic field B0 has an absolute value |B0'|. The two cages are not yet separated, and the cloud is located above the intersection of the two lines, i.e., above point O, at a first height h1 above the XY plane. This starting point is... Figure 3 They share the same starting point t1.

[0195] At tl, by applying microwave power to both guides, at frequency ωa in the case of CPWX1 and at frequency ωb in the case of CPWX2, the two clouds are separated and moved away from the X-axis by a distance d. The first part of the path TX is traveled by atoms at height h1 (see also...). Figure 6 This part of the path is related to... Figure 3 The portion of travel at time t2 is basically the same.

[0196] Next, by modifying the value of the current flowing through the wire and / or by modifying the value of the field B0, the atoms are made to reach a second height h2 at t2 (here h1 < h2 in this example). Then the substantially vertical portion of the path travels a distance w = h2 - h1.

[0197] To reach a height greater than the initial height, the value of the current flowing through W1 needs to be increased from Iw1' to Iw1” (Iw1' < Iw1”) and the value of the current flowing through W2 needs to be increased from Iw2' to Iw2” (Iw2' < Iw2”). A similar effect is obtained by reducing the value of the magnetic field B0 from |B0'| to |B0”| (|B0'| > |B0”). By using these two modifications in combination, as Figure 13 shown in the example, the height value finally reached increases. Calculating the magnetic field generated by this structure allows determination that the distance of the cage to the XY plane is approximately proportional to Iw1 + Iw2 and inversely proportional to |B0|.

[0198] In the example, the height h2 > h1 is reached. Due to the gap between the two clouds and the XY plane, the two clouds do not necessarily remain at a distance of 2d apart as they pass from h1 to h2, and this distance tends to change as the gap between the two clouds and the plane increases. Thus, the path can be substantially parallelogram-shaped rather than rectangular-shaped.

[0199] At t3, the two clouds still at height h2 return to the X-axis by gradually reducing the power applied to the waveguide to zero, and then the clouds travel the second part of the path substantially horizontally at height h2. Another part of the second part at h2 of the path is obtained by inverting the frequency values of the microwaves applied to the waveguides CPWX1 and CPWX2, on the other side of the X-axis (t4, t5). At t5, the current flowing through the wire is returned to its initial value Iw1' (in the case of W1) and Iw2' (in the case of W2) and the magnetic field is returned to its initial value (|B0'|) to return to height h1. Finally, at t6, the microwave power applied to the waveguide is reduced to zero and the two clouds meet.

[0200] Similarly, the path TY' is traveled by “turning on” the waveguides CPWY1 and CPWY2 instead of the waveguides CPWX1 and CPWX2. The values of the waveguide frequencies ω'a and ω'b can be the same or different from the values ωa and ωb.

[0201] To measure the rotational speeds Ωx and Ωy' about the axes X and Y' with the sensor 20, the captured ultracold atomic clouds must travel the path TY at least once (at least 1 loop, although N loops can also be made), and the path TY' at least once (at least 1 loop, although M loops can also be made). These two paths pass sequentially in time. The starting point of the path, here O, is called the initialization intersection point.

[0202] Therefore, in the biaxial inertial sensor 10 according to the invention, waveguides CPWX1, CPWX2, CPWY1, CPWY2, at least one microwave current or voltage generator GMW, wires W1, W2, at least one DC current or voltage generator GDC, and a uniform magnetic field generator GB are configured via at least one processor UT such that the first closed path TX and the second closed path TY' (these paths are respectively contained in a plane perpendicular to X and a plane perpendicular to Y') include at least a first portion located at a first height h1 from the XY plane and a second portion located at a second height h2, where h2>h1, and the transfer from h1 to h2 is achieved via the following:

[0203] - at the first non-zero value (I in the case of W1) W1 '; In the case of W2, it is I W2 ') and the second non-zero value (I in the case of W1) W1 "; In the case of W2, it is I W2 The increase in the DC current value of each conductor between the two conductors, and / or,

[0204] - The decrease in the value of the uniform magnetic field between the first non-zero absolute value |B0'| and the second non-zero value |B0”|.

[0205] Conversely, the first value is passed from the second value to the first height h1 from the second height h2.

[0206] The sensor according to the invention allows for a reduction in axis alignment problems because, within a given chip, the orthogonality of the measurement axes is directly determined by the geometry of the lines on the atomic chip. The microelectronic processes used in atomic chip fabrication allow for the very precise production of the desired wire geometry, thus controlling the orthogonality of the sensor axes.

[0207] According to another aspect, the present invention relates to a method 100 for measuring rotational speeds about two axes X and Y' using an ultracold atom sensor comprising an atom chip as described above.

[0208] The method described below measures the rotational speed about one of axes X and Y', referred to as the measurement axis. To perform measurements about both axes, the method is then applied to the other measurement axis as well.

[0209] In step A, an ultracold atomic cloud 12 is generated, which includes the stages of distributing and cooling atoms at a first height h1 above the XY plane, initializing the atoms to at least one internal state |a>, and trapping the ultracold atomic cloud in a local potential well. The trapping is achieved by passing a direct current through a first wire and a second wire. This step is identical to step A0 described with respect to the prior art. The atoms are trapped at a height h1 above point O, at the intersection of wires W1 and W2.

[0210] In step B, the internal states are initialized by coherently superimposing the ultracold atoms in states |a> and |b> via a first π / 2 pulse. This step is identical to step B0 described with respect to the prior art. The two internal states |a> and |b> are coherently and spatially superimposed at point O.

[0211] In step C, firstly, the atomic cloud of the internal state |a> in one cage T1 is spatially separated from the atomic cloud of the internal state |b> in another cage T2, as is the case in the prior art. Next, the cages are moved in opposite directions along a closed path contained in a plane perpendicular to the measurement axis and initialized perpendicularly to point O. Here, the path lies in a vertical plane perpendicular to X or Y', unlike in the prior art where the path lies in a plane parallel to the XY plane. The path TX or TY' includes a first portion P1 substantially parallel to XY and at a height h1, and a second portion P2 also substantially parallel to XY but at a second height h2 different from h1 (see...). Figure 6 The closed path contains either region A1(TX) or A2(TY'), therefore the atomic function is:

[0212]

[0213] Among them (for A1)

[0214]

[0215] Propelling the captured atomic cloud along a path includes altering its height by applying a voltage or current of a predetermined microwave frequency to first and second guides along the measurement axis (to separate the cage), by alternating microwave frequencies to reverse the two clouds, by applying at least two different values ​​of DC current or voltage to first and second conductors (non-zero values), and / or by applying at least two different values ​​of uniform magnetic field. Various variations are as follows: Figure 11 and 12 The procedure is performed according to a predetermined sequence.

[0216] As described in step C0 of the prior art, it is not a problem to allow the captured atomic cloud to travel at a constant height along a path parallel to the XY plane by continuously "opening" the intersection points. Here, there is only one intersection point O, and the cloud travels along the path at two different heights.

[0217] Once each cloud has traversed the closed path at least once, in step D, the internal states |a> and |b> are recombinated by applying a second π / 2 pulse to the ultracold atoms, and then the atomic density in the internal state selected from |a> or |b> is measured (same as in the prior art).

[0218] Finally, in step E, the Sagnac phase shift of the ultracold atom and the rotational speed of the sensor about the measurement axis (here, X or Y') are determined using formula (8).

[0219] According to one embodiment, sensor 20 is configured to also perform clock measurements. For this purpose, steps A, B, D, and E are performed. Step C is replaced by step cHor, where the power in the waveguide remains zero and the currents in wires W1 and W2 remain constant. At the end of step cHor, the wavefunction is:

[0220]

[0221] in:

[0222]

[0223] During step cHor, the oscillator that generates the π / 2 pulse accumulates the phase ωt, where ω / 2π is the frequency of the oscillator.

[0224] Next, in a step similar to step D, the second π / 2 pulse transfers the phase difference to the totality of the two atomic states:

[0225]

[0226]

[0227] Step E allows for the measurement of at least one of the two populations, which allows for the determination of the difference between the frequency reference ω0 / 2π given by the atom and the frequency ω / 2π of the oscillator.

[0228] According to one embodiment, sensor 20 is configured to also perform acceleration measurements along at least one of axes X or Y', referred to as the measurement axis. The example given below illustrates acceleration a along X. x Measurement.

[0229] To this end, steps A and B are performed, and then, during the Ramsey time, in step CAc, the microwave fields in the two microwave guides perpendicular to the measurement axis (here, X) are gradually turned on. By selecting the correct frequencies for the two microwave fields (see reference Ammar, M.; Dupont-Nivet, M.; Huet, L.; Pocholle, J.-P.; Rosenbusch, P.; Bouchoule, I.; Westbrook, CI; Estève, J.; Reichel, J.; Guerlin, C. & Schwartz, S. "Symmetric microwave potentials for interferometry with thermal atoms on a chip", Phys. Rev. A, American Physical Society, 2015, 91, 053623, Physical Review A, 91, 053623, 2015), the two states |a> and |b> can be spatially separated by a distance d along the X-axis.

[0230] Therefore, during step CAc, the accumulated phase is:

[0231]

[0232] Next, at the end of step CAc, the two microwave fields are gradually turned off to recombine the two states.

[0233] Finally, in a step similar to step D, the second π / 2 pulse transfers the phase difference to the totality of the two atomic states:

[0234]

[0235]

[0236] In a step similar to step E, the population in at least one of two states, |a> or |b>, is measured to determine the acceleration. Therefore, for acceleration measurements along the axis, the atomic cloud travels a one-dimensional path along the same axis.

[0237] To measure the acceleration a along Y' y The procedure used is the same as that used to measure acceleration along the X-axis, except that two microwave fields are sent to a guide perpendicular to Y' (instead of a guide perpendicular to X). This allows the states |a> and |b> to be separated along the Y' axis. Therefore, the phase is accumulated in the same way:

[0238]

[0239] This invention also relates to an atomic chip, further comprising multiple wires placed parallel to a first wire W1 to form a first plurality of wires WP1, and multiple wires placed parallel to a second wire W2 to form a second plurality of wires WP2, as shown. Figure 14 As shown. The conductor index in the first set of multiple conductors is i (index i varies from 1 to I), and the conductor index in the second set of multiple conductors is j (index j varies from 1 to J). Typically, I and J consist of approximately a few to ten / dozens of conductors. These two sets of multiple conductors are located on different layers and are electrically insulated from each other.

[0240] The projections of the first plurality of conductors WP1(i) and the second plurality of conductors WP2(j) onto the XY plane define the intersection point C(i,j) in the XY plane. Since the lines are placed on two different planes, they do not physically intersect in the XY plane. The role of the intersection point is to locate the two conductors that define it; the intersection point is referred to as "on" when a DC current or voltage is applied to these two lines. Furthermore, the first and second plurality of conductors are arranged such that at least one set of intersection points lies within the parallelogram formed by the four waveguides. Point O is one of the intersection points in this set, among others.

[0241] Using a chip with this specific structure in a sensor allows the latter to perform measurements around / along three axes X, Y', and Z. The invention also relates to such a 3-axis sensor 30.

[0242] The rotational speeds of the 3-axis sensor according to the invention about X and Y' are measured in the same manner as described above, except that the closed paths TX and TY' can be initialized from intersections other than O, these intersections being referred to as the first initialization intersection Cx and the second initialization intersection Cy, respectively. For proper sensor operation, Cx is preferably located on the X-axis (equidistant from the two X-direction guides) and Cy is preferably located on the Y'-axis (equidistant from the Y'-direction guides). To simplify sensor implementation, it is best to make points Cx and Cy coincide with O.

[0243] As described in the prior art, the rotational speed about Z is measured by traveling a path TZ contained in a plane parallel to the XY plane of the chip. The path Tz is initialized from a third intersection point Cz. To generate this path, either an X-axis waveguide or a Y'-axis waveguide can be used. If an X-axis waveguide is chosen, it is preferable to arrange multiple WP1 and WP2 such that the intersection point including Cz (which will be activated when traveling along the path TZ) is placed on the X-axis. Similarly, if a Y'-axis waveguide is chosen, it is preferable that there must be an intersection point (to be activated) on the Y'-axis, including Cz.

[0244] Therefore, the multiple lines WP1 and WP2 are preferably configured such that a subset of the intersection points located within the parallelogram lies on the X-axis and another subset lies on the Y'-axis, as shown below. Figure 13 As shown.

[0245] Figure 15 It is explained that for 8 times t1 to t8, when using the X-direction guide (only the guide shown), the two paths TZ of the captured atomic clouds, the 3 intersection points C(1,1), C(2,2) and C(3,3) are opened in this order, and then in the reverse order. Figure 16 A timing diagram is presented, relating the current applied to the conductor in question, the microwave power and frequency applied to the X-direction guide, and the value of the uniform magnetic field, as a function of time between t1 and t8. Since the applied uniform field has a constant absolute value due to travel at a constant height h along path TZ, and the current in the conductor remains constant between the times of interest,...

[0246] By performing this measurement continuously by activating the X-direction waveguide (and its associated crossover point) and the Y'-direction waveguide (and its associated crossover point), the rotational speed Ω around the Z-axis can be obtained. z The redundancy and therefore more accurate measurement.

[0247] To simplify sensor implementation, point Cz is preferably aligned with O, and this initialization point is compatible with the implementation of two redundant measurements performed from the same initialization point.

[0248] Therefore, the 3-axis sensor 30 allows for the measurement of rotational speed Ω. x Ω y Ω z and acceleration a x and a y .

[0249] The present invention also relates to a method for measuring rotational speeds about three axes X, Y', and Z using a cold atom sensor, the cold atom sensor comprising an atom chip compatible with this measurement, such as... Figure 14 and Figure 17 , Figure 18 or Figure 19 As shown below.

[0250] When measuring around the X-axis, the method is performed in the same manner as for measurements around two axes by implementing steps A to E as previously described. The difference is that the first closed path TX contained here in the plane perpendicular to X is initialized from a first initial intersection point Cx located on the X-axis, which is not necessarily O.

[0251] Similarly, in the case of measurements around the Y' axis, steps A to E above are performed by using a second closed path TY', which is contained in a plane perpendicular to Y' and initialized from a second initialization intersection point Cy located on the Y' axis.

[0252] To measure the rotational speed about the Z-axis, after performing steps A and B, such as the steps described above in step C', the atomic cloud of the internal state |a> in one cage T1 is spatially separated from the atomic cloud of the internal state |b> in another cage T2, and the cages move in opposite directions along a closed path contained in a plane perpendicular to the Z-axis, as described with respect to the prior art, by successively opening the crossover points of interest. Path Tz is initialized from the third initialization crossover point Cz. This path Tz can be described using an X-direction waveguide or a Y'-direction waveguide, and the crossover points must then be placed on the axis of symmetry of the two guides (X represents the X-direction guide, Y' represents the Y'-direction guide). Step C' is achieved by applying a voltage or current of a predetermined microwave frequency along the selected axis to the first and second guides in a predetermined sequence, and applying a DC current or voltage to the conductors in the first and second plurality of conductors to continuously excite the crossover points placed on or near the selected axis. Finally, steps D and E as described above are performed.

[0253] Each of the multiple conductors has a width *l* and a separation distance *d*, which is not necessarily the same for all conductors. Preferably, all conductors have the same width *l* and distance *d*, and conform to the following:

[0254] l / 2≤d≤2l

[0255] This condition allows the cage to be moved from one intersection to the next while minimizing cage deformation.

[0256] According to the first variant, such as Figure 17 As shown, the Y' axis coincides with the Y axis, and these two sets of multiple wires are each parallel to an axis.

[0257] According to the preferred second variant, such as Figure 18 As shown, the Y' axis coincides with the Y axis, and the two multiple lines are perpendicular to each other and form a 45° angle with the X and Y axes. This geometry allows for the orientation of cage-specific axes perpendicular to the guide. The cage has an ellipsoidal shape, and the specific axis is the axis of that ellipsoidal shape.

[0258] according to Figure 18 A sub-variant of the variant, which in Figure 19 As shown, the generation of a uniform magnetic field (also known as a bias field) is integrated into an atomic chip by adding wires.

[0259] Two conductors CB1 and CB1', parallel to each other and perpendicular to the conductor of WP1, and preferably placed outside the parallelogram, have been added to the layer of WP1 to allow a bias field perpendicular to CB1 and CB1' to be applied when a DC current is applied to these two conductors. Similarly, two conductors CB2 and CB2', extending perpendicular to the conductor of WP2, have been added to the layer of WP2 to allow a bias field perpendicular to CB2 and CB2' to be applied.

[0260] This configuration has the advantage of integrating the generation of the bias field into the chip.

[0261] According to another aspect, the present invention relates to a matrix array atom chip, for example in Figures 20 to 23 As described in [the text].

[0262] According to the first variant of the AchM atomic chip, this variant is in Figure 20 and Figure 21 As shown, the chip includes a first group of first conductive lines W1n (N lines) with index n and a second group of second conductive lines W2m (M lines) with index m. They are perpendicular to each other and form the rows and columns of a matrix array, respectively. Each first conductive line W1n coincides with an axis Xn (the X-axis with index n), and each second conductive line W2m coincides with an axis Ym (the Y-axis with index m).

[0263] With this arrangement, the guides CPWX1n and CPWX2n along axis Xn are therefore common to all pixels in row n, and the guides CPWY1m and CPWY2m along axis Ym are therefore common to all pixels in column m.

[0264] Each pixel of the matrix array then forms a basic chip Ach(n, m), as described above (see [reference]). Figure 9 The basic chips arranged in this matrix array are located on the same substrate.

[0265] The basic chip integrated into the sensor allows for multiple measurements in parallel of quantities selected from ax and / or ay and / or Ωx and / or Ωy. They can also measure time t. Furthermore, they can be reconfigured to perform other measurements in a different sequence.

[0266] Measurements of ax and Ωy require the Y-direction guide (column) to be enabled, and measurements of Ay and Ωx ​​require the X-direction guide (row) to be enabled.

[0267] Preferably, such as Figure 2 As shown, each layer includes elements selected from the following types: coplanar guides along X1 to XN, coplanar guides along Y1 to YM, conductors WP11 to WP1N, and conductors WP21 to WP2M.

[0268] Figure 20 The illustration shows a first non-limiting example of using the matrix array chip AchM to generate a measurement component.

[0269] In this example, N = M = 6. Columns C1 and C2 are used to measure ax, columns C5 and C6 are used to measure Ωy, and column C3 is used to measure time t. Acceleration ax and rotational speed are each measured in parallel by 2x6 basic chips, while time is measured in parallel by 6 chips, which allows for more accurate measurements. Column C4 is not used in this measurement sequence.

[0270] To make it clearer, the chip used for measurement was painted in gray shade.

[0271] Figure 21 Another non-limiting example using the matrix array chip AchM is illustrated. The chip in column C1 measures ax, the chip in column C2 measures Ωy, the chip in row L1 measures ay, and the chip in row L2 measures Ωx. Since the measurements require a specific sequence for the desired coplanar guides, the latter cannot be shared in two simultaneous measurements of two different inertial parameters. Therefore, the basic chip 4 surrounded by circles is not used.

[0272] The matrix array chip is therefore reconfigured as needed: the desired measurement type (ax, ay, Ωx, Ωy, t), the desired accuracy (which depends on the number of chips performing the measurement simultaneously), etc. Thus, parallel, redundant, and / or complementary measurements are performed on the same matrix array chip.

[0273] This variant has the advantage of being easy to control, but the orientation of the cage (specific axis) relative to the waveguide is not optimal.

[0274] According to the second variant of the atomic chip AchM', this variant is in Figure 22 and Figure 23 As shown, the chip includes a first group of first wires W1n and a second group of second wires W2m, which are perpendicular to each other and form a matrix array, as described above.

[0275] Each of the first wire with index n and the second wire with index m is oriented at 45° to the Xk axis and 45° to the Yl axis, respectively (similar to...). Figure 10 The basic chip). The guides CPWX1k and CPWX2k along axis Xk are therefore common to all pixels on the first diagonal Dk of the matrix array, and the guides CPWY1l and CPWY2l along axis Y1 are therefore common to all pixels on the second diagonal D1'.

[0276] Figure 22 A first non-limiting example of using a matrix array chip AchM' to generate a measurement component is shown.

[0277] In this example, N = M = 6. The first five diagonals, D1' to D5', from southwest to northeast, are used to measure ax; the sixth diagonal, D6', is used to measure t; and the seventh to eleventh diagonals, D7' to D11', are used to measure Ωy. All chips in the matrix array AchM' are used in this example.

[0278] Figure 23 Another non-limiting example using the matrix array chip AchM' is illustrated. Diagonal D5' measures ax, and diagonal D6' measures Ωy.

[0279] Diagonal D6 measures Ωx, and diagonal D7 measures ay. Therefore, for the same reason as above, the basic chip 5 surrounded by circles is not used.

[0280] This variant is more difficult to control than the previous variant, but has the advantage of good orientation of the cage (specific axis) relative to the waveguide.

[0281] To enable the matrix array chip to measure Ωz, according to a third variant that can be combined with the first two variants, in the matrix array chip, at least one wire of the first or second group is replaced by a plurality of mutually parallel wires, a portion of which is included in an associated parallelogram (here, a rectangle) (see...). Figure 17 and Figure 18 (Basic chip).

[0282] According to another aspect, the present invention relates to a cold atom sensor 40, which includes a matrix array chip AchM or AchM', and also includes, as described in the aforementioned sensor:

[0283] - An atomic source S arranged to generate an ultracold atomic cloud near the XY plane of the atomic chip,

[0284] -Uniform magnetic field B0 generator GB,

[0285] - At least one processor UT, at least one DC current or voltage generator GDC suitable for controlling the current in the control wire, and at least one microwave current or voltage generator GMW connected to the waveguide.

[0286] - SDET is a system used to detect light intensity.

[0287] This sensor is suitable for using the aforementioned basic chip and for measuring, as needed and in a reconfigurable manner, at least one acceleration ax or ay and / or a rotational velocity Ωx and / or Ωy in at least one direction corresponding to the axis Xn and / or the axis Ym. It may also be suitable for measuring time, and, if applicable, rotational velocity Ωz (third atom chip variant).

Claims

1. An atomic chip Ach for an ultracold atomic sensor, the chip comprising an XY plane perpendicular to the Z-axis, the XY plane being defined by an X-axis and a Y-axis perpendicular to the X-axis, the atomic chip comprising: - First coplanar waveguide CPWX1 and second coplanar waveguide CPWX2, suitable for use at their respective angular frequencies ω a and ω b Microwaves are propagated by waveguides that are symmetrically positioned on either side of the X-axis and are referred to as X-direction guides. - First coplanar waveguide CPWY'1 and second coplanar waveguide CPWY'2, suitable for use at their respective angular frequencies ω' a and ω' b For propagating microwaves, the waveguide is symmetrically positioned on either side of an axis and is referred to as a Y'-direction guide: the projection of this axis into the XY plane is along an axis Y' that is different from the X-axis and contained within the XY plane. The X-direction guide and the Y'-direction guide are electrically insulated, and the intersection of the guides forms a parallelogram with center O, which defines the origin of the reference system XYZ. - At least a first conductor W1 and a second conductor W2, whose respective projections in the XY plane intersect O and form an angle greater than or equal to 20° between them, said conductors are suitable for direct current to pass through.

2. The atom chip Ach for an ultracold atom sensor according to claim 1, wherein, The X-direction guide, the Y'-direction guide, the first wire, and the second wire are placed on different layers, each layer being electrically insulated from the adjacent layer, and the layers forming a stack Emp placed on the substrate Sub.

3. The atom chip Ach for an ultracold atom sensor according to claim 1 or 2, wherein, The projection of the first conductor W1 in the XY plane is oriented along the X-axis, and the projection of the second conductor W2 in the XY plane is oriented along the Y'-axis.

4. The atom chip Ach for an ultracold atom sensor according to claim 1, wherein, The Y' axis coincides with the Y axis.

5. The atom chip Ach for an ultracold atom sensor according to claim 1, wherein, The Y' axis coincides with the Y axis, and the corresponding projections of the first conductor and the second conductor in the XY plane are perpendicular to each other and oriented at 45° to the X axis and Y axis, respectively.

6. The atom chip Ach for an ultracold atom sensor according to claim 1 or 2, further comprising: Multiple wires placed parallel to the first wire form a first plurality of wires W1P, and multiple wires placed parallel to the second wire form a second plurality of wires W2P. The projections of the wires in the first plurality of wires and the wires in the second plurality of wires in the XY plane define the intersection points in the XY plane. The first plurality of wires and the second plurality of wires are arranged such that at least one set of intersections are located within the parallelogram.

7. The atom chip Ach for an ultracold atom sensor according to claim 6, wherein, The first plurality of wires and the second plurality of wires are configured such that a subset of the set of intersections lies on the X-axis, and another subset of the set of intersections lies on the Y'-axis.

8. The atom chip Ach for an ultracold atom sensor according to claim 6, wherein, The conductor has a width l, and the distance d between two adjacent conductors is included between 0.5 times and 2 times the width.

9. The atomic chip Ach for an ultracold atomic sensor according to claim 1 or 2, comprising a first group of first conductive lines W1n with index n and a second group of second conductive lines W2m with index m, which are perpendicular to each other and respectively form rows and columns of a matrix array. Each of the first wire with index n and the second wire with index m coincides with axis Xn with index n and axis Ym with index m, respectively. The guides CPWX1n and CPWX2n along the Xn axis are therefore common to all pixels in row n, and the guides CPWY1m and CPWY2m along the Ym axis are therefore common to all pixels in column m. Each pixel of the matrix array forms a basic chip Ach(n,m).

10. The atomic chip Ach for an ultracold atomic sensor according to claim 1 or 2, comprising a first group of first conductive lines W1n with index n and a second group of second conductive lines W2m with index m, which are perpendicular to each other and respectively form rows and columns of a matrix array. Each of the first conductor with index n and the second conductor with index m is oriented at a 45° angle to the axis Xk with index k and at a 45° angle to the axis Y1 with index m. The guides CPWX1k and CPWX2k along the Xk axis are therefore common to all pixels on the first diagonal of the matrix array, and the guides CPWY1l and CPWY2l along the Y1 axis are therefore common to all pixels on the second diagonal. Each pixel of the matrix array forms a basic chip Ach(n,m).

11. The atom chip Ach for an ultracold atom sensor according to claim 9, wherein, At least one conductor in the first group or the second group is replaced by a plurality of parallel conductors, portions of which are included in an associated parallelogram.

12. An ultracold atom sensor 20 that allows measurement of rotational speeds about at least two axes X and Y', comprising: - An atom chip Ach for an ultracold atom sensor as described in any one of claims 1 to 5, which is placed in a vacuum chamber. - An atomic source S arranged to generate an ultracold atomic cloud 12 near the XY plane of the atomic chip, The ultracold atoms have a superposition of internal states |a> and |b> during the initialization phase implemented by the sensor. -Uniform magnetic field B0 generator GB, - At least one processor UT, at least one DC current or voltage generator GDC suitable for controlling the current in the conductor, and at least one microwave current or voltage generator GMW connected to the waveguide. - During the implementation of the sensor, the waveguide, the wire, and, where appropriate, the magnetic field are configured as follows: - Modifying the energy of the ultracold atoms to create potential wells for ultracold atoms in the internal state |a> and for ultracold atoms in the internal state |b>, thereby forming a first ultracold atom cage T1 and a second ultracold atom cage T2, one cage enabling the ultracold atom cloud 12 to be fixed in an internal state different from the other cage at a controlled distance from the measurement plane, and - Spatially separate two cages and move cages T1 and T2 along at least a first closed path TX contained in a plane perpendicular to X and a second closed path TY' contained in a plane perpendicular to Y', each path being traveled in one direction by ultracold atoms from the first cage and in the opposite direction by ultracold atoms from the second cage. The sensor also includes a system SDET for detecting light intensity, which is suitable for measuring at least one population of the ultracold atoms in the internal state.

13. The ultracold atom sensor 20 according to claim 12, which allows for the measurement of rotational speeds about at least two axes X and Y', wherein, The waveguide and the at least one microwave current or voltage generator, the wire and the at least one DC current or voltage generator, and the uniform magnetic field generator are configured such that the first closed path TX and the second closed path TY' each include at least a first portion located at a first height h1 from the XY plane and a second portion located at a second height h2, the second height h2 being strictly greater than the first height, so as to induce a transfer from the first height to the second height in such a way as follows: -At the first non-zero current value I W1 '、I W2 ' and the second non-zero current value I W1 “、I W2 The increase in the DC current value through each conductor between "" and / or, - The decrease in the uniform magnetic field value between the first non-zero magnetic field value B0' and the second non-zero magnetic field value B0”. And the transfer from the second altitude to the first altitude and vice versa.

14. An ultracold atom sensor 30 that allows measurement of rotational speeds about three axes X, Y', and Z, comprising: - An atom chip Ach for an ultracold atom sensor as described in any one of claims 6 to 9, which is placed in a vacuum chamber. - An atomic source, arranged to generate an ultracold atomic cloud 12 near the XY plane of the atomic chip, wherein the ultracold atoms have a superposition of internal states |a> and |b> in an initialized state. -Uniform magnetic field B0 generator GB, - At least one processor, at least one DC current or voltage generator suitable for controlling the current in the conductor, and at least one microwave current or voltage generator connected to the waveguide. -The waveguide and the wire are configured as follows: - Modifying the energy of the ultracold atoms to create potential wells for ultracold atoms in the internal state |a> and for ultracold atoms in the internal state |b>, thereby forming a first ultracold atom cage T1 and a second ultracold atom cage T2, one cage enabling the ultracold atom cloud 12 to be fixed in an internal state different from the other cage at a controlled distance from the measurement plane, and - Spatially separate two cages and move cages T1 and T2 along a first closed path TX, initialized from a first initialization intersection point Cx on the X-axis in a plane perpendicular to X; a second closed path TY', initialized from a second initialization intersection point Cy on the Y'-axis in a plane perpendicular to Y'; and a third closed path TZ, initialized from a third initialization intersection point Cz on point O in a plane perpendicular to Z. Each path is formed by the ultracold atoms of the first cage traveling in one direction, and by the ultracold atoms of the second cage traveling in the opposite direction. The sensor also includes a system for detecting light intensity, the system being adapted to measure at least one population of the ultracold atoms in the internal state.

15. The ultracold atom sensor 30 according to claim 14, which allows for the measurement of rotational speeds about three axes X, Y', and Z, wherein, The waveguide and the at least one microwave current or voltage generator, the wire and the at least one DC current or voltage generator, and the uniform magnetic field generator are configured such that each of the first closed path TX and the second closed path TY' includes at least a first portion located at a first height h1 from the XY plane and a second portion located at a second height h2, the second height h2 being strictly greater than the first height, so as to induce a transfer from the first height to the second height in such a way as follows: -At the first non-zero current value I W1i '、I W2j ' and the second non-zero current value I W1i “、I W2j Between, by defining the increase of the DC current value of each wire at the associated initial crossover point, and / or, - The decrease in the uniform magnetic field value between the first non-zero magnetic field value B0' and the second non-zero magnetic field value B0”. And the transfer from the second altitude to the first altitude is also reversed.

16. An ultracold atom sensor 40, comprising: -The Atom Chip Ach for an Ultracold Atom Sensor as described in any one of claims 9 to 11, - An atomic source S arranged to generate an ultracold atomic cloud 12 near the XY plane of the atomic chip, -Uniform magnetic field B0 generator GB, - At least one processor UT, at least one DC current or voltage generator GDC suitable for controlling the current in the conductor, and at least one microwave current or voltage generator GMW connected to the waveguide. - SDET system for detecting light intensity The sensor is adapted to measure, as needed and in a reconfigurable manner, at least one acceleration ax, ay and / or a rotational velocity Ωx, Ωy along / around at least one direction corresponding to the axis Xn and / or the axis Ym using the base chip.

17. A method for measuring rotational speeds about two axes X and Y' using an ultracold atom sensor comprising an atom chip, the atom chip being placed in a vacuum chamber and comprising an XY plane perpendicular to the Z-axis, the atom chip comprising: - First coplanar waveguide CPWX1 and second coplanar waveguide CPWX2, which are suitable for use at their respective angular frequencies ω a and ω b Microwaves are propagated by waveguides that are symmetrically positioned on either side of the X-axis and are referred to as X-direction guides. - First coplanar waveguide CPWY'1 and second coplanar waveguide CPWY'2, which are suitable for use at their respective angular frequencies ω' a Microwaves propagate along ω'b, and the waveguide is symmetrically positioned on either side of the following axis and is referred to as the Y'-direction guide: the projection of this axis into the XY plane is along an axis Y' that is different from the X-axis and contained within the XY plane. The X-direction guide is electrically insulated from the Y'-direction guide, and the intersection of the guides forms a parallelogram with center O. Center O defines the origin of the reference system XYZ. At least a first conductor W1 and a second conductor W2, whose respective projections in the XY plane secant the point O and form an angle greater than or equal to 20° between them, are suitable for carrying direct current. To measure the rotational speed about one of the axes X and Y', referred to as the measurement axes, the method includes the following steps: A generates an ultracold atomic cloud 12, which includes the following stages: distributing the atoms at a first height h1 above the XY plane, cooling the atoms, initializing the atoms to at least one internal state |a>, and trapping the ultracold atomic cloud in a local potential well, the trapping being performed by passing a direct current through the first and second wires. B initializes the internal state by coherently superimposing the ultracold atoms between states |a> and |b> via a first π / 2 pulse; C spatially separates the atomic cloud of the internal state |a> in one cage T1 from the atomic cloud of the internal state |b> in another cage T2, and moves the cages T1 and T2 in opposite directions along a closed path contained in a plane perpendicular to the measurement axis and initialized from the point O by: applying a voltage or current of a predetermined microwave frequency to the first and second guides along the measurement axis in a predetermined sequence; applying at least two different DC current or voltage values ​​to the first and second conductors; and / or applying at least two different values ​​of a uniform magnetic field, the path including a portion located at a second height h2 at a distance from the XY plane that is different from the first height h1. D reassembles the internal states |a> and |b> by applying a second π / 2 pulse to the ultracold atoms and then measuring the density of atoms in internal states selected from at least |a> and |b>. E determines the Sagnac phase shift of the ultracold atom and calculates the rotational speed of the sensor about the measurement axis. The method further includes performing steps A through E to measure the rotational speed about another measuring axis.

18. A method for measuring rotational speeds about three axes X, Y', and Z using a cold atom sensor comprising an atom chip, the atom chip being placed in a vacuum chamber and comprising an XY plane perpendicular to the Z-axis, the axes XYZ forming an orthogonal reference system, the atom chip comprising: - First coplanar waveguide CPWX1 and second coplanar waveguide CPWX2, which are suitable for use at their respective angular frequencies ω a and ω b Microwaves are propagated by waveguides that are symmetrically positioned on either side of the X-axis and are referred to as X-direction guides. - First coplanar waveguide CPWY1 and second coplanar waveguide CPWY2, which are suitable for use at their respective angular frequencies ω' a Microwaves propagate along ω'b, and the waveguide is symmetrically positioned on either side of the following axis and is referred to as the Y'-direction guide: the projection of this axis into the XY plane is along a Y'-axis that is different from the X-axis and contained within the XY plane. The X-direction guide is electrically insulated from the Y'-direction guide, and the intersection of the guides forms a parallelogram with center O. Center O defines the origin of the reference system XYZ. - A first plurality of parallel conductors W1P and a second plurality of parallel conductors W2P, wherein the projections of the conductors in the first plurality of conductors and the conductors in the second plurality of conductors in the XY plane define the intersection point. The projections of the plurality of conductors in the XY plane form an angle greater than or equal to 20° between them. The projections of the conductors in the first plurality of conductors and the conductors in the second plurality of conductors in the XY plane intersect at point O. The first plurality of conductors and the second plurality of conductors are arranged such that at least one set of intersection points lies within the parallelogram. The method includes: - Perform steps A to E of the method as described in claim 17 to measure the rotational speed about X, including the first closed path TX in a plane perpendicular to X, initialized from a first initialization intersection point Cx located on the X-axis. - Perform steps A to E of the method as described in claim 17 to measure the rotational speed about Y', wherein the second closed path TY' contained in the plane perpendicular to Y' is initialized from the second initialization intersection point Cy located on the Y' axis, and - Measure the rotational speed about the Z-axis, which corresponds to the measurement axis: - Perform steps A and B of the method as described in claim 17, Step C' includes spatially separating the atomic cloud of the internal state |a> in one cage T1 from the atomic cloud of the internal state |b> in another cage T2, and moving the cages T1 and T2 in opposite directions along a closed path initialized from a third initialization intersection Cz in a plane perpendicular to the Z-axis by: applying a voltage or current of a predetermined microwave frequency to the first guide and the second guide in a predetermined sequence along one of the axes X and Y', wherein the one of the axes X and Y' is referred to as the selection axis; and applying a DC current or voltage to the conductors in the first plurality of conductors and the conductors in the second plurality of conductors, thereby sequentially stimulating the intersections placed on or near the selection axis. - Perform steps D and E as described in claim 17.

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