Uniform intensity collimated light beam generation device based on Powell prism and light beam shaping system

Abstract

The invention discloses a uniform-intensity collimated light beam generating device which comprises a Powell prism and an optical adjusting device, an aspheric curved surface in six optical surfaces of the Powell prism receives parallel light incident in the longitudinal direction, and light spots of the parallel light have light intensity in two-dimensional Gaussian distribution. The first emergent light emitted from the Powell prism has a divergence angle in the first direction. The optical adjusting device adjusts the shape of the first emergent light, so that second emergent light which is collimated in the first direction and is uniformly distributed can be obtained. The invention further discloses a light beam shaping system, the second emergent light is shrunk and focused after passing through the cavity objective lens device and enters the ion lattice in the cavity device, and the diameter of an incident light spot is matched with the feature size of the ion lattice. According to the device and the system, the state that the incident light spots are always in Gaussian distribution is changed, and global laser-ion operation can be completed by using the incident light spots with very small diameters, so that the laser power is saved, and the system performance is improved.

Description

Technical Field

[0001] The present application relates to the fields of optical elements, optical imaging, and laser beam shaping, and particularly to a uniform collimated beam generating device and a beam shaping system based on a Powell prism. Background Art

[0002] In quantum computing systems of ions or atoms and experimental systems of cold atom physics, lasers are required to manipulate ions or atoms. For example, operations such as Doppler cooling, EIT cooling, polarization gradient cooling, quantum initial state preparation, and quantum pumping are performed using lasers. Most of these operations require irradiating ions or atoms with a global laser beam (global light). To obtain a global light field, traditional solutions generally expand, contract, or shape the output light of a laser through an ordinary lens group. Specifically, usually, an ordinary lens is used to change the spot size, or an ordinary cylindrical lens is used to magnify or reduce the spot in a certain direction to generate an elliptical spot. The major axis size of this elliptical spot is similar to the volume of the ion lattice, thereby enabling global operations. However, using the above solutions has significant drawbacks. Because no matter how the incident spot is shaped, the power of the generated elliptical spot still follows a two-dimensional Gaussian distribution, and ions at different positions in the spot plane will experience significantly different light power densities. In addition, the actual light intensity utilization rate of a Gaussian spot is low because the light intensity difference between the periphery and the center of the spot is large, resulting in more wasted light power outside the threshold. To alleviate this problem, it is usually necessary to irradiate ions with a laser spot much larger than the size of the ion crystal, so that each ion is within a range where the power density change rate in the center of the spot is small. Such a technical means cannot fundamentally solve the problem of uneven spot power, and often requires expanding the spot a lot, wasting limited laser power, and further causing the total laser power to fail to meet the requirements of high-speed quantum logic gates, laser cooling, and quantum computing.

[0003] On the other hand, in order to achieve stable trapping of a larger-scale ion crystal in an ion quantum computing system, a cryogenic system is required to place the ion lattice at an ultra-low temperature of about 4K. Since the cryogenic refrigeration system needs to use a refrigerator to achieve ultra-low temperature refrigeration, there is generally a problem of low-frequency vibration of the ion trap, which is manifested as the vibration amplitude at the sample of the cryogenic ion trap system being about 100nm, and the vibration frequency being about 50Hz. This will cause the ions in the cryogenic system to have an additional vibration of at least several tens of nanometers compared to the ambient temperature system environment. This additional vibration will cause the light intensity felt by the ions to be constantly changing, thereby additionally reducing the fidelity of the logic gate, or reducing the effects of laser-ion operations such as laser cooling, optical pumping, and quantum initial state preparation, and further affecting the final effect of ion quantum computing.

[0004] In summary, controlling the shape and size of the light spot, especially transforming the Gaussian optical power distribution of the incident light spot into a uniform distribution within the size range of the ion lattice, is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The present invention provides a uniform intensity collimated light beam generating device and a beam shaping system based on a Powell prism, so as to at least solve the technical problems existing in the prior art that the incident light spot always presents a Gaussian light power distribution and the size of the incident light spot does not match the size of the ion lattice.

[0006] According to one aspect of the present application, a uniform-intensity collimated light beam generating device is provided, the device comprising a first Powell prism and an optical adjustment device, the aspheric curved surface of the first Powell prism faces the incident light, the optical adjustment device is placed on the side of the outgoing light of the Powell prism, the central axis of the first Powell prism coincides with the optical axis of the optical adjustment device, serving as the optical axis of the uniform-intensity collimated light beam generating device, the direction of the optical axis being the longitudinal direction of the uniform-intensity collimated light beam generating device; the aspheric curved surface receives parallel light incident along the longitudinal direction, the light spot of the parallel light has a Gaussian distribution of light intensity in a first direction perpendicular to the longitudinal direction; the light exit surface of the first Powell prism is parallel to the first direction, and a first outgoing light is emitted from the light exit surface; the first outgoing light has a divergence angle in the first direction, and the light spot of the first outgoing light has a uniform distribution of light intensity in the first direction; the optical adjustment device receives the first outgoing light, and emits a second outgoing light from the light exit surface of the optical adjustment device, the second outgoing light is collimated in the first direction, and the light spot of the second outgoing light has a uniform distribution of light intensity in the first direction.

[0007] Optionally, the light intensity of the spot of the parallel light in a second direction perpendicular to the longitudinal direction presents a Gaussian distribution, and the first direction and the second direction are perpendicular to each other.

[0008] Optionally, the divergence angle of the first emitted light in the first direction is calculated by the following formula:

[0009]

[0010] Where n = n air / n lens is the ratio of the refractive index of air to the refractive index of the material of the first Powell prism, and the expression of the parameter t is:

[0011]

[0012] Wherein h is the diameter of the spot of the parallel light in the first direction, c and Q are the surface parameters in the surface equation of the aspherical surface, wherein the surface equation of the aspherical surface is:

[0013]

[0014] Optionally, the diameter of the light spot of the parallel light in the first direction does not exceed the maximum dimension of the aspherical surface in the first direction.

[0015] Optionally, the optical adjustment device includes an aspherical lens and a cylindrical lens. The aspherical lens faces and receives the first emitted light, and the cylindrical lens is disposed on the side of the emitted light of the aspherical lens. The emitted light of the cylindrical lens is the second emitted light. The aspherical lens converges the first emitted light, and the cylindrical lens adjusts the width of the emitted light of the aspherical lens in the second direction.

[0016] Optionally, the light spot of the second emitted light is elliptical, the major axis of the ellipse is along the first direction, the minor axis is along the second direction, and the light intensity in the direction of the major axis of the ellipse is uniformly distributed.

[0017] Optionally, the uniform collimated light beam generating device further includes a second Powell prism. The aspherical surface of the second Powell prism faces the light-emitting surface of the first Powell prism. The light-emitting surface of the second Powell prism is parallel to the second direction. The optical adjustment device faces the light-emitting surface of the second Powell prism, and the light intensity of the light spot of the second emitted light in the second direction is uniformly distributed.

[0018] According to another aspect of the present application, there is provided a beam shaping system. The beam shaping system includes a laser, the aforementioned uniform collimated light beam generating device, an in-cavity objective device, a cavity device, and an ion lattice. The ion lattice is located at the exact center of the cavity device. The ion lattice is oriented along the first direction. The exact center of the cavity device is on the optical axis of the uniform collimated light beam generating device. The axis of the cavity device coincides with the optical axis and also coincides with the optical axis of the in-cavity objective device. The laser generates output light, and the parallel light incident longitudinally is generated from the output light. The in-cavity objective device faces and receives the second emitted light emitted from the optical adjustment device, and the third emitted light is emitted from the light-emitting surface of the in-cavity objective device. The third emitted light is convergent in the first direction and is emitted in the direction towards the optical axis. The third emitted light enters the cavity device and interacts with the ion lattice at the position of the ion lattice. The light intensity of the light spot of the third emitted light at the position of the ion lattice along the first direction is uniformly distributed, and the characteristic diameter of the light spot in the first direction matches the characteristic dimension of the ion lattice in the first direction.

[0019] Optionally, the in-chamber objective lens device includes a first lens group and a second lens group. The first lens group faces and receives the second outgoing light, and the second lens group is disposed on the side of the outgoing light of the first lens group. The outgoing light of the second lens group is the third outgoing light. The first lens group is used to adjust the aspect ratio of the elliptical beam profile of the second outgoing light, and the second lens group is used to adjust the beam size of the outgoing light of the first lens group.

[0020] Further optionally, the first lens group includes at least two cylindrical lenses that extend along a second direction, and the second lens group includes any one of the following: a common lens; an achromatic lens; and an objective lens system with an NA greater than a predetermined threshold.

[0021] Optionally, the light spot of the third outgoing light at the ion lattice position is elliptical, with the major axis of the ellipse along the first direction and the minor axis along the second direction, and the light intensity in the direction of the major axis of the ellipse is uniformly distributed.

[0022] The uniform collimated beam generating device of the present disclosure uses a Powell prism and an optical adjustment device, and can generate an outgoing light collimated along a specific direction. The light intensity of the light spot of the outgoing light is uniformly distributed along this specific direction, thereby changing the state where the light intensity of the incident light spot always exhibits a Gaussian distribution, so that the global laser-ion operation in quantum computing can avoid the influence of additional vibrations on the ions.

[0023] Furthermore, the beam shaping system of the present disclosure uses an in-chamber objective lens device to reduce and focus the collimated beam generated by the uniform collimated beam, so as to match the characteristic size of the ion lattice, enabling the global laser-ion operation in quantum computing to be completed with a very small incident light spot, saving laser power and improving system performance. And because the light intensity distribution can be uniformly distributed, the light intensity felt by the ion qubits will not be affected by mechanical vibrations, thereby improving the logical gate guarantee.

[0024] Those skilled in the art will become more apparent about the above and other objects, advantages and features of the present application according to the following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Some specific embodiments of the present application will be described in detail hereinafter with reference to the accompanying drawings in an exemplary but not restrictive manner. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0026] Figure 1 is an optical path diagram of a uniform collimated beam generating device according to an embodiment of the present application;

[0027] Figure 2 It is the optical path diagram of a beam shaping system according to an embodiment of the present application;

[0028] Figure 3 It shows the optical path diagram of an embodiment of the present application when the aspherical lens L1 has an aspherical surface in a single direction;

[0029] Figure 4A It shows the collimation effect diagram (i.e., near-field energy distribution) of the diverging beam in the x direction passing through the Powell prism at the Figure 3 B1 position;

[0030] Figure 4B It shows the collimation effect diagram (i.e., far-field energy distribution) of the diverging beam in the x direction passing through the Powell prism at the Figure 3 B2 position;

[0031] Figure 5A It shows the energy distribution in the two-dimensional plane of the light spot at the ion lattice of the diverging beam in the x direction passing through the Powell prism; Figure 3 at the ion lattice;

[0032] Figure 5B It shows the energy distribution in the x direction at the ion lattice; Figure 5C It shows the energy distribution in the y direction;

[0033] Figure 6 It shows a schematic diagram without optical adjustment using A2;

[0034] Figure 7A It shows Figure 6 the energy distribution (near-field energy distribution) at the B1 position in

[0035] Figure 7B It shows Figure 6 the light energy distribution (far-field energy distribution) at the B2 position in Detailed implementation manners

[0036] It should be noted that, without conflict, the embodiments in the present disclosure and the features in the embodiments may be combined with each other. The present disclosure will be described in detail below with reference to the drawings and in combination with the embodiments.

[0037] In order to enable those skilled in the art to better understand the solution of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without making creative efforts shall fall within the protection scope of the present disclosure.

[0038] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present disclosure are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances so as to implement the embodiments of the present disclosure described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0040] Figure 1 is an optical path diagram of a uniform collimated beam generating device according to an embodiment of the present application. Generally, the device may include a Powell prism P and an optical adjustment device A2. The optical adjustment device A2 is placed on the side of the outgoing light of the Powell prism P, and the optical axes of the lenses in A2 coincide with the central axis of the Powell prism P, which is defined as the optical axis of the uniform collimated beam generating device, and this direction is defined as the z-axis direction. The direction perpendicular to the optical surfaces S4 and S5 of the Powell prism is defined as the x-axis, and a rectangular coordinate system is established. The incident collimated parallel light 1 is incident on the Powell prism P along the positive z-axis direction. The shape of the parallel light 1 in the x-y plane is the incident light spot, and the light intensity distribution of the incident light spot is a two-dimensional Gaussian distribution, that is, the light intensity of the incident light spot along the x-axis is in the form of a Gaussian function, and the light intensity at x = 0 (i.e., on the optical axis) is the largest, and the light intensity on both sides of x = 0 decreases in the form of a Gaussian function; the light intensity of the incident light spot along the y-axis is in the form of a Gaussian function, and the light intensity at y = 0 (i.e., on the optical axis) is the largest, and the light intensity on both sides of y = 0 decreases in the form of a Gaussian function. The incident light spot is a single-mode Gaussian spot output by the laser, usually a circular spot, and the diameter of the spot in the x direction is h, as Figure 1 shown.

[0041] The Powell prism P includes six optical surfaces S1, S2, S3, S4, S5, and S6. Among them, the S1 surface is a customized curved surface defined by a curved surface equation (the curved surface equation will be described later). The S2 to S6 surfaces are all flat surfaces. The vertex of the curved surface of the S1 surface is placed on the optical axis. The S4 and S5 surfaces are parallel to the optical axis, the S6 surface is perpendicular to the optical axis, and the S2 and S3 surfaces are symmetrically placed on both sides of the optical axis. The S1 surface is used to receive incident light. A large amount of spherical aberration is generated on its aspherical curved surface, and the beam energy distribution is redistributed. The light intensity of the light field after exiting from the aspherical curved surface is evenly distributed. The specific optical path is as follows: Parallel light 1 is incident on the S1 surface and then refracts into the Powell prism. The refracted light 2 passes through the optical axis and is incident on the S6 surface. After passing through the S6 surface, it refracts and exits the Powell prism. The refracted light 2 is divided into two segments. The refracted light 2.1 before passing through the optical axis is a converging light and is incident from the S1 surface towards the optical axis. The refracted light 2.2 after passing through the optical axis is a diverging light and reaches the S6 surface. After being refracted by the S6 surface, the divergence angle of the refracted light 2.2 further increases, and the outgoing light 3 exits the Powell prism at a divergence angle θ. It can be seen from this that the Powell prism P refracts the incident light 1 twice in the x direction, as Figure 1 shown. The first refraction occurs on the S1 surface. This refraction changes the energy distribution of the incident light spot in the x direction, changing from a Gaussian distribution to a uniform distribution, and has a converging effect on the incident light. The second refraction occurs on the S6 surface. This refraction changes the diverging light with a smaller divergence angle inside the prism into a diverging light with a larger divergence angle and exits the prism, so that the light intensity of the outgoing light 3 of the Powell prism reaches a uniform distribution within a relatively large fan-shaped divergence angle θ. Therefore, the function of the Powell prism P is: to convert a collimated Gaussian beam into a diverging beam with a uniform light intensity distribution.

[0042] The S1 surface of the Powell prism P is an aspherical curved surface, and its surface shape in the x-z plane can be described by the following equation:

[0043]

[0044] where c is the curvature at the vertex of the curved surface, and Q is the conic constant. For different c and Q, the curved surface forms given by formula (1) are different. Therefore, c and Q can be used as optimization parameters, and c and Q can be optimized according to the target quantities such as the required divergence angle and the diameter of the outgoing light spot in combination with an optimization algorithm to design the surface shape of the S1 surface that meets the requirements of the target quantities. In order to ensure that the light intensity of the light spot exiting from the Powell prism is evenly distributed, the incident light spot cannot exceed the curved surface range given by formula (1). Combining Figure 1 , that is, it is required that the diameter h of the single-mode Gaussian light spot in the x direction cannot exceed the maximum size of the S1 surface in the x direction given by formula (1).

[0045] When the diameter h of the incident light spot in the x direction and the surface equation of the S1 surface are determined, the divergence angle θ of the outgoing light 3 of the Powell prism can be determined. Through research and calculation, the applicant of the present disclosure obtained the functional expression form of the divergence angle θ as follows:

[0046]

[0047] where n = n air / n lens is the ratio of the refractive index of air to the refractive index of the material of the Powell prism. The expression of the parameter t is:

[0048]

[0049] The parameter t is a function of the surface parameters c, Q, and the diameter h of the incident light spot in the x direction, and can be regarded as a new dimension quantity generated after the light spot diameter h acts on the S1 surface, which is called the variant diameter.

[0050] The outgoing light 3 of the Powell prism is all within the range of the divergence angle θ given by formula (2). The light intensity of the outgoing light within this range is uniformly distributed in the x direction. When the divergence angle θ is determined, the size of the light spot of the outgoing light 3 in the x direction is related to the height dimension D0 of the Powell prism P in the z direction, that is, the z coordinate z s1 at the vertex of the S1 surface, and the z coordinate z s6 of the S6 plane, and the distance d0 between the receiving screen and the S6 surface of the Powell prism P. When the optical adjustment device A2 is used as the receiving screen, let the lens closest to the S6 surface of the Powell prism P in A2 be L1. The z coordinate when the surface of L1 facing the S6 side intersects the z axis is denoted as z left-L1 , z left-L1 The absolute value of the difference between s6 and z left-L1 is d0. The diameter of the light spot of the outgoing light 3 in the x direction at the position z = z left-L1 is denoted as h1, and h1 is the diameter of the light spot incident on the optical adjustment device A2. From the above analysis, when the divergence angle θ is determined, h1 is related to D0 and d0. If any one of D0 or d0 takes a larger value, the value of h1 is larger. When a larger outgoing light spot is required at the receiving position, the optical adjustment device A2 can be moved away from the S6 surface to obtain a larger h1 value.

[0051] The optical adjustment device A2 is composed of more than one lens. Typically, A2 includes an aspherical lens with a short focal length and a cylindrical lens with a short focal length. As Figure 1 shown, the aspherical lens L1 faces the outgoing light 3 of the Powell lens P and has a focal length f1. A cylindrical lens L2 is arranged on the outgoing light side of L1, and L2 has a focal length f2. The z coordinate when the surface of L1 facing away from the S6 side intersects the z axis is denoted as z right-L1The z - coordinate when the surface of L2 facing L1 intersects the z - axis is denoted as z left-L2 , z left-L2 The absolute value of the difference from z right-L1 is denoted as d1, and d1 represents the distance between L2 and L1.

[0052] The divergent outgoing light 3 diverging in the x - direction, after being refracted by the aspherical lens L1, the divergence angle of the outgoing light 4 is reduced. Thus, when the fan - shaped divergence angle θ of the Powell prism P is too large, the divergence angle of the outgoing light 3 of the Powell prism P can be reduced by the aspherical lens L1, avoiding the spot size far exceeding the tolerance of the subsequent system due to the too - large fan - shaped divergence angle θ of the Powell prism.

[0053] The outgoing light 4 of the aspherical lens L1, after being refracted by the cylindrical lens L2, the outgoing light 5 becomes parallel light parallel to the optical axis. Thus, the cylindrical lens L2 can limit the range of the outgoing light 4 diffusing in the x - axis direction, facilitating subsequent shaping. And because the cylindrical lens L2 adjusts and compresses the width of the outgoing light of the aspherical lens L1 in the y - direction, the outgoing light 5 is close to a line - light source distributed only in the x - direction. Specifically, the spot of the outgoing light 5 is elliptical, the major axis of the ellipse is along the x - axis, the minor axis is along the y - axis, the size of the major axis is much larger than that of the minor axis, and the spot has a uniform light - intensity distribution along the x - axis direction.

[0054] Although Figure 1 it is shown in [reference] that the optical adjustment device A2 includes an aspherical lens L1 and a cylindrical lens L2, the number of the aspherical lens L1 and the cylindrical lens L2 can also be more. In addition, as an alternative example, of course, in fact, the aspherical lens L1 and the cylindrical lens L2 can also be combined together to form an aspherical cylindrical mirror, and the non - spherical surface is in a single direction.

[0055] Specifically, Figure 3 a schematic diagram showing that L1 is an aspherical surface in a single direction is shown. Referring to Figure 1 as shown, where the focal length of L1 is 35 mm, the focal length of L2 is 50 mm, and the in - cavity objective device A3 can be equivalent to a fixed - focal - length lens with a focal length of 75 mm. The parallel light 1 is, for example, Gaussian light with a diameter of 1 mm.

[0056] Figure 4A shows the collimation effect diagram (i.e., near - field energy distribution) of the diverging light beam in the x - direction passing through the Powell prism at the B1 position in Figure 3 . Figure 4B shows the collimation effect diagram (i.e., far - field energy distribution) of the diverging light beam in the x - direction passing through the Powell prism at the B2 position in Figure 3 .

[0057] Figure 5Ashows the energy distribution of the light spot at the ion lattice of the diverging light beam in the x direction passing through the Powell prism Figure 3 ; Figure 5B shows the energy distribution in the x direction at the ion lattice; Figure 5C shows the energy distribution in the y direction.

[0058] In addition, for comparison, Figure 6 shows a schematic diagram without using the optical adjustment device A2 for optical adjustment. Among them Figure 7A shows the energy distribution (near-field energy distribution) at the B1 position; Figure 7B shows the light energy distribution (far-field energy distribution) at the B2 position. By Figure 7A and Figure 7B it can be seen that when only using one Powell lens without using the optical adjustment device A2, the light beam will diverge very quickly, and it can spread dozens of centimeters from the B1 position to the B2 position, completely exceeding the scale of the ions and the width of the optical elements.

[0059] Therefore, the optical adjustment device A2 first uses the aspherical lens L1 to limit the beam divergence. At this time, it is a divergence limit for the X direction, and the Y direction is actually a short-focus system. Then the optical adjustment device A1 uses at least one cylindrical lens to adjust the outgoing light 4 of the aspherical lens L1 into an approximately collimated state or a state of focusing together in a long range in both the XY directions, so as to facilitate the adjustment of the subsequent optical system.

[0060] In addition, the focal lengths of the aspherical lens L1 and the cylindrical lens L2 are usually less than 60 mm, preferably between 25 mm and 55 mm.

[0061] The optical adjustment device A2 only adjusts the spot shape, size and divergence degree of the incident light, and does not change the light intensity distribution of the spot of the incident light, that is, the spot of the incident light is uniformly distributed along a certain direction, and the spot of the outgoing light is still uniformly distributed along this direction. The spot of the incident light is Gaussian distributed along another direction,

[0062] and the spot of the outgoing light is still Gaussian distributed along this direction. None of the lens elements in the optical adjustment device A2 has the function of changing the light intensity distribution. The change of the light intensity distribution is realized by the Powell prism P. Specifically, it is completed by the S1 surface of the Powell prism P. Specifically for Figure 1 , the S1 surface of the Powell prism P changes the light intensity distribution of the spot of the incident light 1 in the x direction, but does not change the light intensity distribution in the y direction, that is, the light intensity of the outgoing light 3 in the x direction is uniformly distributed, but the light intensity in the y direction is still Gaussian distributed. The outgoing light 3 at z = z left-L1It is incident on the optical adjustment device A2 with a size of the light spot diameter h1 in the x direction. After being refracted by each lens in A2, the outgoing light 6 is approximately collimated (or focused in a sufficiently long range) with a size of the light spot diameter h2 in the x direction. The light intensity along the x direction is uniformly distributed, the light intensity along the y direction is Gaussian distributed, and it is still collimated along the y direction. In this embodiment, a Powell prism is not used to change the light intensity distribution of the incident light 1 along the y direction because the ion crystal on which the light is finally focused is a one-dimensional ion chain or the major axis of a long elliptical ion lattice. Therefore, it is sufficient for the light intensity to be uniformly distributed in a single direction, and the Gaussian distribution of the light intensity in the direction perpendicular to the above direction does not affect the experimental results. However, if the ion crystal requires homogenization in both directions of the two-dimensional structure, then the light intensity needs to be uniformly distributed in both the x direction and the y direction. At this time, another Powell prism P' can be added after the light exit surface S6 of the Powell prism P in Figure 1 . The S4 surface and the S5 surface of P' are perpendicular to the y-axis. P' is used to change the light intensity distribution of the light spot of the incident light 1 along the y direction from Gaussian distribution to uniform distribution. However, since the outgoing light 3 from the light exit surface S6 of the Powell prism P already has a large divergence angle, the S1 surface of the Powell prism P' needs a large size to cover the range of the outgoing light. In addition, a biaxial prism system can also be used, that is, the curved surface equation has similar curvatures that vary with the z function in both the x and y directions. Thus, the present application can determine the divergence angles θ x and θ y of the light spot in the x direction and the y direction according to the expected required light spot shape. Furthermore, the curved surface equation and curvature of the Powell prism P in the x direction and the curved surface equation and curvature of the Powell prism P' in the y direction can be determined. At this time, the optical adjustment device A2 can directly use isotropic circular lenses and achromatic lenses L1 without using a single-direction cylindrical lens L2, and the requirements of approximate collimation can be achieved. The size aspect ratio and homogenization are directly realized by customizing the biaxial prism system.

[0063] In the above embodiment, the optical adjustment device A2 includes two lenses L1 and L2, but this does not limit the present disclosure. The optical adjustment device A2 can use three or more lenses, and each lens has a focal length size and a spacing size from the adjacent lens. Taking the size of the required light spot diameter h2 as the target quantity, reasonably select the types of lenses, and optimize the focal length size and the spacing size between adjacent lenses with an optimization algorithm to design lenses that meet the target quantity requirements to form the optical adjustment device A2.

[0064] Figure 2It is an optical path diagram of a beam shaping system according to an embodiment of the present application. The beam shaping system generally may include a laser A1, a uniform collimated beam generating device, an in-cavity objective device A3, a cavity device A4, and an ion lattice CY. The uniform collimated beam generating device includes a Powell prism P and an optical adjustment device A2. The Powell prism P receives the parallel light 1 incident along the positive z-axis generated by the laser A1. The light spot of the parallel light 1 on the x-y plane is a single-mode Gaussian light spot, usually a circular light spot, and the diameter of the light spot in the x direction is h. The ion lattice CY is at the exact center of the cavity device A4, and CY is the long axis of a one-dimensional ion chain or an elliptical ion lattice. The inside of the cavity device A4 is usually vacuum. The in-cavity objective device A3 is arranged after the optical adjustment device A2, and the optical axes of the lenses in A3 coincide with the optical axis of the uniform collimated beam generating device. A3 receives the outgoing light 6 of the uniform beam generating device. The light intensity of the light spot of the outgoing light 6 along the x direction is uniformly distributed, and the light intensity along the y direction is Gaussian-distributed. The diameter of the light spot in the x direction is h2. The outgoing light 6 is collimated along the x direction and is refracted by the lenses in A3 and output as the outgoing light 7. The outgoing light 7 is a converging light towards the optical axis. The outgoing light 7 enters the cavity device A4 and continues to be incident on the ion lattice CY. The z coordinate of the position where the ion lattice CY is located is set as z CY , and the incident light 7 interacts with the ion lattice CY at z = z CY to generate laser-ion operations such as laser cooling, quantum pumping, quantum initial state preparation, etc. The light intensity of the light spot of the incident light 7 at z = z CY along the x direction is uniformly distributed, and the light intensity along the y direction is Gaussian-distributed. The diameter of the light spot in the x direction is h0, and h0 matches the characteristic dimension L x-CY of the ion lattice CY along the x direction. The meaning of "matching" here is that the value of h0 meets the minimum requirement of being greater than the value of L x-CY . h0 may be slightly greater than L x-CY , but the value of h0 is as small as possible. Thus, the size of the incident light spot along the x direction is matched with the characteristic dimension of the ion lattice along the x direction, and the light intensity within the size of the incident light spot along the x direction is uniformly distributed.

[0065] The in-cavity objective device A3 is composed of more than one lens. Typically, A3 includes a first lens group OL1 and a second lens group OL2. As Figure 2 shown, the first lens group OL1 faces the outgoing light 6 of the optical adjustment device A2 and has a focal length f OL1 . The second lens group OL2 is arranged on the outgoing light side of the first lens group OL1, and the second lens group OL2 has a focal length f OL2 . The z coordinate when the curved surface on the side of the first lens group OL1 facing away from A2 intersects the z axis is denoted as z right-OL1When the curved surface of the second lens group OL2 facing the first lens group OL1 intersects the z-axis, the z-coordinate is denoted as z left-OL2 , z left-OL2 The absolute value of the difference from z right-OL1 is denoted as d OL1 , d OL1 represents the distance between OL2 and OL1.

[0066] The first lens group OL1 includes at least two cylindrical lenses to adjust the aspect ratio of the elliptical beam profile of the outgoing light 6 of the optical adjustment device A1. The second lens group OL2 includes any one of the following: a common lens, an achromatic lens, and an objective lens system with a numerical aperture greater than a predetermined threshold, for adjusting the beam size of the outgoing light of the first lens group OL1. The outgoing light 7 of the second lens group OL2 is output as the outgoing light of the in-chamber objective device A3. The z-coordinate when the outgoing surface of the second lens group OL2 intersects the z-axis is denoted as z right-OL2 , and the spot diameter of the outgoing light 7 in the x-direction at the position z = z right-OL2 is denoted as h3. The in-chamber objective device A3 converts the uniform incident light 6 with a diameter of h2 and collimated in the x-direction into a uniform outgoing light 7 with a diameter of h3 and converging in the x-direction. The outgoing light 7 continues to propagate in the positive z-axis direction for a distance of D CY and then reaches the ion lattice CY, where D CY represents the distance between the ion lattice CY and the outgoing surface of A3, and its magnitude is equal to the absolute value of the difference between z CY and z right-OL2 . When the convergence angle of the outgoing light 7 is determined, the larger D CY , the smaller the spot diameter h0 of the spot in the x-direction at z = z CY . For a given ion lattice CY, its characteristic dimension L x-CY in the x-direction is also determined. In order to make the spot diameter h0 of the spot in the x-direction at z = z CY match L x-CY , the cavity device A4 and the ion lattice CY can be moved along the z-axis away from or closer to A3, so that D CY increases or decreases, thereby making h0 match L x-CY . Preferably, the size of the spot at the focal length of the second lens group OL2 matches the lattice.

[0067] Thus, the spot of the outgoing light 7 of the in-chamber objective device A3 is an approximate ellipse. Through the focusing of the in-chamber objective device A3, the spot size of the outgoing light 7 at the ion position is approximately the same as the size of the ion lattice. Preferably, the focal point position of the second lens group OL2 is at the ion position (on the Z-axis). In addition, here in order to make the spot size at the ion crystal completely match, a cylindrical lens can also be set inside the in-chamber objective device A3 to reshape the outgoing light once again.

[0068] The in-chamber objective lens device A3 only adjusts the convergence condition, size, and exit angle of the incident light, without changing the light intensity distribution of the spot of the incident light. That is, the spot of the incident light is uniformly distributed along a certain direction, and the spot of the exit light is still uniformly distributed along this direction. The spot of the incident light is Gaussian distributed along another direction, and the spot of the exit light is still Gaussian distributed along this direction. Each lens element in A3 does not have the function of changing the light intensity distribution. Specifically, the light intensity of the spot of the incident light 6 is uniformly distributed along the x direction and Gaussian distributed along the y direction. After the action of A3, the spots of the exit light 7 at z = z right-OL2 position and at z = z CY position have a uniform light intensity distribution along the x direction and a Gaussian light intensity distribution along the y direction. If it is required that the spots of the exit light 7 are uniformly distributed in both the x direction and the y direction, then a Powell prism P' or a biaxial prism system needs to be added.

[0069] In the above embodiments, the in-chamber objective lens device A3 includes two first lens groups OL1 and OL2, but this does not limit the present disclosure. The in-chamber objective lens device A3 can use three or more lenses, and each lens OL i has a focal length dimension f OLi and a spacing dimension d from the adjacent lens OLi . At this time, the types of each OL i in A3 and the values of f OLi and d OLi need to be determined according to the size of the cavity device A4, that is, the distance between the ion lattice CY and the edge of the cavity device A4, and the size of h0. The L x-CY value of the ion lattice CY is generally within 1 μm. When the distance between the ion lattice CY and the edge of the cavity device A4 is 150 mm, an ellipse of 500 μm × 50 μm is usually required for the spot at z = z CY to meet the general size of a one-dimensional ion chain or the major axis of an elliptical ion lattice. Among them, 500 μm is the diameter of the spot at z = z CY along the x direction, that is, the h0 value, and 50 μm is the diameter of the spot at z = z CY along the y direction. For the incident light 1 with h = 2 mm, the working distance of the in-chamber objective lens device A3 can be set, for example, between 75 mm and 200 mm, and the numerical aperture NA can be taken as 0.02 to 0.4. On this basis, the types of each OL i and the values of f OLi and d OLi can be designed.

[0070] It should be noted that in the above embodiments, the spot of the incident light 1 on the x-y plane is a single-mode Gaussian spot, usually a circular spot. However, the output light of the laser A1 does not necessarily always guarantee single-mode. Sometimes the Gaussian light contains multi-mode components, and the spot shape is not a perfect circle. At this time, the f i and d i values of each lens L i in the optical adjustment device A2 can be changed so that the output light 6 can still meet the preset shaping target. In addition, in the above embodiments, the incident light 1 is set as parallel light, that is, the incident light 1 is collimated. However, the output light of the laser A1 may not be collimated. At this time, a collimation-expansion or collimation-compression lens group can be added after the laser A1 so that the incident light incident on the S1 surface of the Powell prism P is collimated light, and the incident spot does not exceed the curved surface range of S1.

[0071] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and values of the components and steps set forth in these embodiments do not limit the scope of the present disclosure. At the same time, it should be understood that for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0072] For the sake of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" etc. can be used here to describe the spatial positional relationship between a device or feature shown in the figure and other devices or features. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figure for the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations are made for the spatial relative descriptions used here.

[0073] In the description of the present disclosure, it should be understood that the orientation or positional relationship indicated by orientation words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom", etc. is usually based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present disclosure and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of the present disclosure; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0074] As described above, the above are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A uniform collimated light beam generating device, characterized in that, The device includes a first Powell prism (P) and an optical adjustment device (A2). The aspherical surface (S1) of the first Powell prism (P) faces the incident light. The optical adjustment device (A2) is placed on the side of the outgoing light of the Powell prism (P). The central axis of the first Powell prism (P) coincides with the optical axis of the optical adjustment device (A2), which serves as the optical axis of the uniform collimated light beam generating device, and the direction of this optical axis is the longitudinal direction of the uniform collimated light beam generating device. The aspherical surface (S1) receives the parallel light (1) incident along the longitudinal direction, and the light intensity of the spot of the parallel light in the first direction (x) perpendicular to the longitudinal direction is Gaussian-distributed. The outgoing surface (S6) of the first Powell prism (P) is parallel to the first direction (x), and the first outgoing light (3) exits from the outgoing surface (S6). The first outgoing light (3) has a divergence angle (θ) in the first direction (x), and the light intensity of the spot of the first outgoing light in the first direction (x) is uniformly distributed. The optical adjustment device (A2) receives the first outgoing light (3) and emits the second outgoing light (6) from the outgoing surface of the optical adjustment device (A2). The second outgoing light (6) is collimated in the first direction (x), and the light intensity of the spot of the second outgoing light in the first direction (x) is uniformly distributed.

2. The device according to claim 1, characterized in that ,, The light intensity of the spot of the parallel light is Gaussian-distributed in the second direction (y) perpendicular to the longitudinal direction, and the first direction (x) and the second direction (y) are perpendicular to each other.

3. The device according to claim 2, characterized in that, The divergence angle (θ) of the first outgoing light (3) in the first direction (x) is calculated by the following formula: where n = n air / n lens is the ratio of the refractive index of air to the refractive index of the material of the first Powell prism, and the expression of the parameter t is: where h is the diameter of the spot of the parallel light in the first direction (x), and c and Q are the surface type parameters in the surface type equation of the aspherical surface (S1). The surface type equation of the aspherical surface (S1) is:

4. The device according to claim 2, characterized in that, The optical adjustment device (A2) includes an aspherical lens (L1) and a cylindrical lens (L2). The aspherical lens (L1) faces and receives the first outgoing light (3), and the cylindrical lens (L2) is arranged on the side of the outgoing light of the aspherical lens (L1). The outgoing light of the cylindrical lens (L2) is the second outgoing light (6). The aspherical lens (L1) converges the first outgoing light (3), and the cylindrical lens (L2) adjusts the width of the outgoing light of the aspherical lens (L1) in the second direction (y).

5. The device according to claim 4, characterized in that, The spot of the second outgoing light (6) is elliptical, the major axis of the ellipse is along the first direction (x), the minor axis is along the second direction (y), and the light intensity in the direction of the major axis of the ellipse is uniformly distributed.

6. The device according to any one of claims 2-5, characterized in that, The uniform collimated light beam generating device further includes a second Powell prism (P'), the aspherical surface of the second Powell prism (P') faces the light-emitting surface (S6) of the first Powell prism (P), the light-emitting surface of the second Powell prism (P') is parallel to the second direction (y), the optical adjustment device (A2) faces the light-emitting surface of the second Powell prism (P'), and the light intensity of the spot of the second emitted light is uniformly distributed in the second direction (y).

7. An ion operating system, characterized in that, The ion operating system includes a laser (A1), the uniform collimated light beam generating device as described in any one of claims 1-6, an in-chamber objective device (A3), a chamber device (A4), and an ion lattice (CY). The ion lattice (CY) is located at the exact center of the chamber device (A4). The longest axis of the ion lattice (CY) is oriented along the first direction (x). The exact center of the chamber device (A4) is located on the optical axis of the uniform collimated light beam generating device. The axis of the chamber device (A4) coincides with the optical axis and also coincides with the optical axis of the in-chamber objective device (A3). The laser (A1) generates output light, and the parallel light (1) incident longitudinally is generated from the output light; the in-cavity objective lens device (A3) faces and receives the second output light (6) exiting from the optical adjustment device (A2), and the third output light (7) exits from the light-emitting surface of the in-cavity objective lens device (A3). The third output light (7) is convergent in the first direction (x) and exits toward the optical axis direction; the third output light (7) enters the cavity device (A4) and interacts with the ion lattice (CY) at the position of the ion lattice (CY). The light intensity of the spot of the third output light (7) at the position of the ion lattice (CY) is uniformly distributed along the first direction (x), and the characteristic diameter (h0) of the spot in the first direction (x) matches the characteristic dimension (L x-CY ) of the ion lattice (CY) in the first direction (x).

8. The system according to claim 7, wherein The in-chamber objective device (A3) includes a first lens group (OL1) and a second lens group (OL2). The first lens group (OL1) faces and receives the second emitted light (6). The second lens group (OL2) is arranged on the side of the emitted light of the first lens group (OL1). The emitted light of the second lens group (OL2) is the third emitted light (7). Wherein the first lens group (OL1) is used to adjust the aspect ratio of the elliptical beam profile of the second emitted light (6), and the second lens group (OL2) is used to adjust the beam size of the emitted light of the first lens group (OL1).

9. The system according to claim 8, wherein The first lens group (OL1) includes at least two cylindrical lenses, and the at least two cylindrical lenses extend along the second direction, and The second lens group (OL2) includes any one of the following: a common lens; an achromatic lens; and an objective lens system with a numerical aperture greater than a predetermined threshold value.

10. The system according to claim 8, wherein The spot of the third emitted light (7) at the position of the ion lattice (CY) is elliptical. The major axis of the ellipse is along the first direction (x), and the minor axis is along the second direction (y). The light intensity in the direction of the major axis of the ellipse is uniformly distributed.

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