On-chip Atom Sensor with Symmetric Waveguides
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Solution Overview
Problem
The existing configuration of conductive wires and microwave waveguides in cold atom sensors on atomic chips faces challenges in creating identical potential minima for ultracold atom traps, leading to issues like atomic losses, low signal-to-noise ratio, and inefficient cooling, which hinders accurate rotational speed measurement.
Innovation Solution
The proposed solution involves a chip design with a specific topology of conductive wires and waveguides that allows for the creation of non-secant microwave waveguides and conductive wires arranged symmetrically, enabling the generation of ultracold atom traps with identical potential minima, reducing atomic losses, and facilitating efficient cooling and coherent superposition of internal states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional conductive wires and microwave waveguides are used to create atom traps, then the device can be manufactured, but the potential minima cannot be made identical, leading to curvature differences and reduced coherence time
Solution Approach 1:
The patent employs asymmetric wire configurations where conductive wires are positioned at different distances from the measurement plane. Specifically, first conductive wires are at a first distance while second conductive wires are at a second distance, creating non-secant arrangements that enable identical potential minima curvature despite different spatial positions. This asymmetric positioning compensates for surface roughness effects and achieves the required potential identity.
Solution Approach 2:
The patent transitions from planar (2D) wire arrangements to three-dimensional (3D) non-secant configurations. By positioning wires at different heights (distances from measurement plane) and orientations, the system creates traps with identical curvature in three-dimensional space, overcoming the limitations of flat chip surfaces and enabling precise rotational velocity measurement.
2Ease of manufacture
If surface roughness is present in the chip, then manufacturing is simplified, but atom reflection increases and dispersion increases, making Sagnac effect measurement impossible
Solution Approach 1:
The patent introduces an intermediary electromagnetic field mechanism where microwave waveguides create potential minima that elevate atoms above the rough chip surface. The atoms are trapped in electromagnetic potential wells at distances of several micrometers from the surface, mediating the interaction between atoms and the rough substrate, thereby preventing direct contact and reflection while maintaining trap stability.
Solution Approach 2:
The patent replaces direct mechanical contact between atoms and the chip surface with electromagnetic field-based trapping. Instead of relying on physical waveguide structures that atoms might collide with, the system uses microwave-induced potential minima to confine atoms in free space above the chip, substituting mechanical confinement with electromagnetic confinement.
3Device complexity
If conventional wire topology is used, then device complexity is reduced, but signal-to-noise ratio decreases due to atomic losses and trap imperfections
Solution Approach 1:
The patent segments the trapping function into multiple independent conductive wire groups positioned at different heights and orientations. First conductive wires create potential minima at a first distance from the measurement plane, while second conductive wires create potential minima at a second distance, allowing independent optimization of each trap and reducing cross-interference that degrades signal quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the coherence time of the interferometer, improves the signal-to-noise ratio, and enables precise rotational speed measurements by minimizing the effects of surface roughness and curvature differences in the traps.
Implementation Method 1
The combination of the potentials created by the waveguides and the conductive wires, combined with the homogeneous magnetic field, is supposed to create two minima of potential constituting two three-dimensional cold atom traps
Implementation Method 2
The rotation measurements on this type of device are carried out by exploiting the Sagnac effect. The phase shift θ induced by the Sagnac effect between two counter-rotating matter waves in a reference frame rotating at the angular speed Ω
Implementation Method 3
The combination of the potentials created by the waveguides and the conductive wires, combined with the homogeneous magnetic field, is supposed to create two minima of potential
Data Source
Figure 1~2
Figure 3a~3c
Figure 4a~4b
AI summary
Ultracold atoms sensor allowing rotational velocity to be measured about a measurement axis (14), said sensor comprising: means suitable for generating first and second ultracold atom traps (T1, T2), one trap allowing a cloud of ultracold atoms (12) to be immobilised in an internal state different from the other trap, at a preset distance from said measurement plane, said means comprising ◊ at least first and second waveguides (CPW1, CPW2) that are suitable for propagating microwaves with angular frequencies ωa and ωb, said waveguides being non-secant and placed symmetrically with respect to an axis called the axis of symmetry (Sy), ◊ and conductive wires integrated into said chip (1) and suitable for passing DC currents; said means being configured to modify the energy of said ultracold atoms so as to create a potential minima for the ultracold atoms in the internal state |a> and a potential minima for the ultracold atoms in the internal state |b>, thus forming said first and second ultracold atom traps, and to move said traps (T1, T2) along a closed path (16), said path being traced in one direction by the ultracold atoms of the first trap and in the opposite direction by the ultracold atoms of the second trap.