Phase stabilization system of optical lattice and phase stabilization method thereof
Through the design of the optical signal detection device and adjustment component, the position of the mirror is adjusted by using the PID controller and the piezoelectric brake, the phase jitter problem of the optical lattice imaging component is solved, and the relative phase locking between the light fields is achieved, which improves the stability and accuracy of the experiment.
Patent Information
- Application Number
- CN202510918667.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-03
- Publication Date
- 2025-08-15
AI Technical Summary
Optical lattice imaging components are prone to phase jitter under external influence, resulting in phase instability of the one-dimensional optical lattice and affecting the experimental effect.
The optical signal detection device and adjustment components are adopted to adjust the distance between the reflector and the prism group through the PID controller and the piezoelectric brake, eliminate phase drift errors, and achieve the locking of the relative phase between the light fields.
It effectively eliminates phase drift errors, keeps the one-dimensional optical lattice in a stable state, ensures the locking of relative phases between the light fields, and improves the stability and accuracy of the experiment.
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Figure CN120491307A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of optical lattice imaging, and in particular to a phase stabilization system of an optical lattice and a phase stabilization method thereof. Background Art
[0002] An optical lattice is a periodic pattern of potential wells formed within a standing wave field generated by the interference of multiple laser beams. The spatial period of the potential wells is on the order of the laser wavelength, allowing atoms to be trapped, cooled, and confined within the array. Because the arrangement of atoms within such an array resembles a "crystal structure" in solid-state physics, it is called an optical lattice. Optical lattices are important research tools for experimentally simulating many-body systems and have significant applications in atomic clocks, quantum state manipulation, the study of coherent state properties, and quantum computing.
[0003] In related technologies, an optical lattice imaging assembly includes a light source, a reflector, and a lens assembly. Part of the light emitted by the light source passes through a prism assembly and directly enters the lens assembly. Part of the light is incident on the reflector, reflected by the reflector, and then enters the lens assembly. Under external influences, some structural components within the optical lattice imaging assembly may shift slightly, causing the optical path difference / arm length difference between the two interfering light beams of the optical lattice imaging assembly to change. This can cause phase jitter in the one-dimensional optical lattice and affect the experiment. Summary of the Invention
[0004] In order to solve one of the above technical problems, the present invention provides a phase stabilization system of an optical lattice and a phase stabilization method thereof.
[0005] The present invention adopts the following technical solutions:
[0006] In a first aspect, embodiments of the present application provide a phase stabilization system for an optical lattice, comprising:
[0007] An optical lattice imaging assembly comprising an optical signal detection device, an optical assembly, and a light source, the optical assembly comprising a reflector, a prism group, and a lens group, the prism group being located between the light source and the reflector, the prism group comprising a first polarization beam splitting prism and a second polarization beam splitting prism, wherein a portion of light emitted by the light source passes through the first polarization beam splitting prism and is incident on the lens group and the optical signal detection device in sequence, and a portion of light passes through the reflector, and light reflected by the reflector passes through the second polarization beam splitting prism and is incident on the lens group and the optical signal detection device in sequence;
[0008] An adjustment component, wherein the input end of the adjustment component is connected to the optical signal detection device, and the output end of the adjustment component has a brake, and the brake and the reflector are in transmission cooperation to adjust the distance between the reflector and the prism group to eliminate phase drift error, keep the one-dimensional optical lattice in a stable state, and achieve relative phase locking between light fields.
[0009] Optionally, the regulating component includes a PID controller;
[0010] The brake is a piezoelectric brake;
[0011] The PID controller is electrically connected to the piezoelectric brake;
[0012] The piezoelectric brake is connected to the reflector in a transmission manner to adjust the position of the reflector.
[0013] Optionally, the phase stabilization system of the optical lattice is characterized by comprising a high voltage amplifier;
[0014] An input end of the high-voltage amplifier is connected to the PID controller, and an output end of the high-voltage amplifier is electrically connected to the piezoelectric driver.
[0015] Optionally, the phase stabilization system of the optical lattice includes a lock-in amplifier;
[0016] The input end of the lock-in amplifier is connected to the optical signal detection device, and the output end of the lock-in amplifier is electrically connected to the PID controller.
[0017] Optionally, the optical signal detection device is an EMCCD device.
[0018] A second object of the present application is to provide a phase stabilization method for the phase stabilization system of the optical lattice, comprising:
[0019] The regulating component obtains a frequency discrimination signal from an output signal of the optical signal detecting device;
[0020] The adjustment component controls the brake to adjust the position of the reflector in the optical lattice imaging component according to the frequency discrimination signal to eliminate the phase drift error, keep the one-dimensional optical lattice in a stable state, and achieve relative phase locking between light fields.
[0021] Optionally, the regulation component includes a lock-in amplifier and a PID controller;
[0022] The lock-in amplifier obtains a signal from the position with the largest slope in the traveling wave of the output signal as a frequency discrimination signal, and sends the frequency discrimination signal to the PID controller. The PID controller generates an output signal according to the frequency discrimination signal to control the brake to adjust the position of the reflector.
[0023] Optionally, the lock-in amplifier compares the received output signal with a reference signal and performs a difference calculation. If the relative phase value is not zero, the lock-in amplifier sends a frequency discrimination signal to the PID controller.
[0024] Optionally, the phase-locked amplifier and the optical signal detection device are electrically connected, and the TTL trigger pulse signal set in the phase-locked amplifier is sent to the trigger input end of the optical signal detection device, so that the reference signal of the phase-locked amplifier is synchronously triggered with the trigger signal of the optical signal detection device.
[0025] Optionally, the lock-in amplifier and the light source are electrically connected, frequency modulation is applied to the light source, and the frequency of the reference signal of the lock-in amplifier is set to be consistent with the laser modulation frequency of the light source.
[0026] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings are part of this application and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:
[0028] Figure 1 A schematic diagram of a phase stabilization system of an optical lattice provided by an embodiment of the present disclosure is shown;
[0029] Figure 2 A module structure diagram of a phase stabilization system of an optical lattice provided by an embodiment of the present disclosure is shown.
[0030] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION
[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.
[0032] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.
[0033] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "mounted" and "connected" should be understood broadly. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.
[0034] Example 1
[0035] An optical lattice is a periodic pattern of potential wells formed within a standing wave field generated by the interference of multiple laser beams. The spatial period of the potential wells is on the order of the laser wavelength, allowing atoms to be trapped, cooled, and confined within the array. Because the arrangement of atoms within such an array resembles a "crystal structure" in solid-state physics, it is called an optical lattice. Optical lattices are important research tools for experimentally simulating many-body systems and have significant applications in atomic clocks, quantum state manipulation, the study of coherent state properties, and quantum computing.
[0036] like Figure 1 and Figure 2 As shown, an embodiment of the present application provides a phase stabilization system for an optical lattice, comprising: an optical lattice imaging component and an adjustment component. The optical lattice imaging component has an optical signal detection device, an optical component and a light source. The light source can be a laser source. The optical component includes a reflector, a prism group and a lens group. The prism group is located between the light source and the reflector. The prism group includes a first polarization beam splitting prism and a second polarization beam splitting prism. Part of the light emitted by the light source passes through the first polarization beam splitting prism and is incident on the lens group and the optical signal detection device (such as the EMCCD device in the figure). Part of the light is incident on the reflector, which can be a total reflection mirror. The reflector is perpendicular to the light emission direction of the light source. The light reflected by the reflector passes through the second polarization beam splitting prism and is incident on the lens group and the optical signal detection device in sequence. The input end of the adjustment component is connected to the optical signal detection device, and the output end of the adjustment component has a brake. The brake and the reflector are in transmission cooperation to adjust the distance between the reflector and the prism group to eliminate phase drift errors, keep the one-dimensional optical lattice in a stable state, and achieve relative phase locking between light fields.
[0037] In this application, the optical lattice imaging component verifies that the phase jitter of a one-dimensional optical lattice is caused by changes in the optical path difference / arm length difference between the two interfering light beams. Experiments have shown that under external influences, the optical path difference / arm length difference between the two interfering light beams can easily change, causing the phase jitter of the one-dimensional optical lattice. This application compensates for the phase difference and eliminates phase drift errors by adjusting the design of the component, keeping the one-dimensional optical lattice in a stable state and achieving relative phase locking between the light fields.
[0038] like Figure 2 As shown, the prism assembly of the optical lattice imaging assembly includes a first polarization beam splitting prism and a second polarization beam splitting prism. The reflector, the second polarization beam splitting prism, the first polarization beam splitting prism, and the light source are arranged in sequence along a straight line, and the first polarization beam splitting prism and the second polarization beam splitting prism are arranged symmetrically. Part of the light emitted by the light source passes through the first polarization beam splitting prism and is incident on the lens assembly and the optical signal detection device in sequence. Part of the light is incident on the reflector. The light reflected by the reflector passes through the second polarization beam splitting prism and is incident on the lens assembly and the optical signal detection device in sequence.
[0039] In some possible embodiments, the optical lattice shaping component includes a quarter wave plate and a half wave plate, wherein the half wave plate is located between the light source and the first polarization beam splitter prism, and the quarter wave plate is located between the second polarization beam splitter prism and the reflector.
[0040] A half-wave plate is an optical element that alters the polarization state of light through birefringent materials. Its core function is to introduce a phase difference of π to linearly polarized light, rotating its polarization direction by a specific angle. This application incorporates a half-wave plate before light beam splitting to align the polarization of the light. A quarter-wave plate is used to introduce a phase delay of an odd multiple of π / 2, enabling conversion between linearly polarized light, circularly polarized light, and elliptically polarized light.
[0041] The lens assembly may include a first lens, a second lens, and a third lens, with the prism assembly, the first lens, the second lens, the third lens, and the optical signal detection device disposed sequentially. Two light beams emitted by the light source ultimately pass through the first lens, the second lens, and the third lens in sequence and are incident on the optical signal detection device. The two light beams are split by a polarization beam splitting prism and then combined between the first lens and the second lens, where they interfere at the beam intersection, forming a one-dimensional optical lattice. The light then passes through the second lens and the third lens and is incident on the optical signal detection device.
[0042] The optical signal detection device can be a photodetector and an oscilloscope, or an EMCCD device, which can monitor the one-dimensional optical lattice through the real-time incident optical signal. The movement of the interference fringes reflects the relative change in the displacement of the interference arm length.
[0043] In some possible implementations, the adjustment component includes a PID controller, the brake is a piezoelectric brake, the PID controller and the piezoelectric brake are electrically connected, and the piezoelectric brake and the reflector are transmission-connected to adjust the position of the reflector.
[0044] PID controllers, such as the Sim960, are high-performance analog PID controllers that combine the fast response of analog circuits with the flexibility of digital interfaces, making them suitable for both scientific research and industrial applications. The basic principle of PID control is this: the PID controller calculates the error (e(t) = target value - current value). The target value is the theoretical value under normal conditions, and the current value is a frequency-determining signal sent to the PID controller in real time. The controller then adjusts the control variable (u(t)) to stabilize the system at the target value. Its mathematical expression is:
[0045]
[0046] Among them, Kp is the proportional gain (adjusts the response speed, but may cause overshoot), Ki is the integral gain (eliminates steady-state error, but may cause oscillation), and Kd is the differential gain (suppresses overshoot and enhances stability).
[0047] The brake is a piezoelectric brake, such as piezoelectric ceramics. Changing the working voltage of the piezoelectric ceramics can relatively compensate for the displacement, so that the stripes of the optical signal detection device can move in the opposite direction and return to the equilibrium position.
[0048] In some possible embodiments, the regulating component includes a high-voltage amplifier, wherein an input end of the high-voltage amplifier is connected to the PID controller, and an output end of the high-voltage amplifier is electrically connected to the piezoelectric driver. The high-voltage amplifier can boost the input signal to a required high voltage range, thereby driving the actuator to move.
[0049] In some possible implementations, the phase stabilization system of the optical lattice includes a lock-in amplifier, an input end of the lock-in amplifier is connected to the optical signal detection device, and an output end of the lock-in amplifier is electrically connected to the PID controller.
[0050] The SR830 lock-in amplifier is an experimental device for weak signal detection. By comparing the detected signal with a reference input signal, it extracts signals with the same frequency and phase characteristics as the reference signal. Similar to an analog correlator, it uses the mutual independence of signal and noise to suppress noise. It consists of a signal channel, a reference channel, a phase-sensitive detector, a low-pass filter, and a DC amplifier. The signal channel utilizes a low-noise differential amplifier and a band-stop filter for signal amplification and noise reduction, removing high-order terms and excess noise. The reference channel provides a frequency reference signal. The operating principle of the lock-in amplifier is based on the Fourier transform. Its output is a DC voltage signal proportional to the amplitude of the input signal that has the same frequency and phase information as the reference signal. Other frequency components in the input signal will not have any impact on the output signal of the lock-in amplifier.
[0051] The optical signal detector converts the optical signal into an electrical signal and transmits it to a lock-in amplifier. The lock-in amplifier uses the two locations with the largest slopes in the traveling wave of the electrical signal (or optical signal) as frequency discrimination signals to feed back to a PID controller. A PID controller is a real-time sampling linear controller that performs proportional integration on the error signal and reduces errors by comparing the input error signal with the output control signal in real time. When the interference fringes change, indicating phase drift, the optical signal detector converts the received optical signal into a voltage signal and transmits it to the lock-in amplifier. The input signal is compared with a reference signal and the difference is calculated. If the relative phase value is non-zero, the output signal of the lock-in amplifier is fed back to the PID controller. The feedback signal is finally amplified by high voltage and controls the expansion and contraction of the piezoelectric ceramic (actuator), which drives it to adjust the position of the 0° total reflector with nanometer-level precision. This feedback compensates for phase differences and eliminates phase drift errors, maintaining the one-dimensional optical lattice in a stable state and achieving relative phase locking between the optical fields.
[0052] In some possible implementation schemes, the optical signal detection device may be an EMCCD device, and the model may be IXonUltra888. The EMCCD device replaces the traditional ordinary optical signal detection device to observe the changes in interference fringes. When the traditional optical signal detection device is used, the diameter of the two interference light spots is too thin, the spot size is smaller than the detection area of the optical signal detection device, and the two beams of light have a certain angle, and it is difficult to determine the position of the optical lattice formed by precise interference. Moreover, after the optical signal detection device is connected to the oscilloscope, it is impossible to demodulate the optical signal according to the obtained voltage signal curve. However, the present application adopts an EMCCD device, which can directly observe the optical lattice image formed by interference, and when adjusting the overlap of the two interference light beams, the image captured by the EMCCD device can be used as a reference, which greatly reduces the difficulty of adjusting the overlap of the interference light.
[0053] In some possible implementations, the lock-in amplifier and the optical signal detection device are connected via a BNC-to-SMA cable, and a BNC-to-SMA cable is used between the lock-in amplifier and the EMCCD device. This allows the TTL trigger pulse signal set in the lock-in amplifier to be connected to the EMCCD's external trigger input, so that the lock-in amplifier's reference signal and the EMCCD trigger signal are triggered synchronously. Specifically, the rising (or falling) edge of the signal triggers the EMCCD device to capture the optical lattice. This ensures that the exposure time of the EMCCD device is synchronized with the time of the lock-in amplifier's demodulated signal.
[0054] In some possible implementations, a lock-in amplifier and the light source are connected via a BNC cable. Frequency modulation is applied to the laser light source via the lock-in amplifier. The reference frequency of the reference signal terminal within the lock-in amplifier is set to be consistent with the laser modulation frequency (e.g., both are set to 5 kHz). The lock-in amplifier and the laser are connected via a BNC cable, and the lock-in amplifier is used to apply frequency modulation to the optical signal.
[0055] It should be noted that the modulation method applied to the optical signal is not limited to the lock-in amplifier, and intensity modulation or frequency modulation can also be applied to the optical signal through external devices such as AOM, EOM, etc.
[0056] Example 2
[0057] A second embodiment of the present application provides a phase stabilization method for the above-mentioned phase stabilization system of the optical lattice, comprising:
[0058] The regulating component obtains a frequency discrimination signal from an output signal of the optical signal detecting device;
[0059] In this step, a lock-in amplifier is used to extract a frequency discrimination signal from the output signal. By comparing the signal with a reference input signal, the lock-in amplifier extracts the signal from the optical signal detection device's output signal that has the same frequency and phase characteristics as the reference signal. The reference signal can be a set value based on the actual situation.
[0060] The adjustment component controls the brake to adjust the position of the reflector in the optical lattice imaging component according to the frequency discrimination signal to eliminate the phase drift error, keep the one-dimensional optical lattice in a stable state, and achieve relative phase locking between light fields.
[0061] The regulation components include a lock-in amplifier and a PID controller;
[0062] The lock-in amplifier obtains a signal from the position with the largest slope in the traveling wave of the output signal as a frequency discrimination signal, and sends the frequency discrimination signal to the PID controller. The PID controller generates an output signal according to the frequency discrimination signal to control the brake to adjust the position of the reflector.
[0063] Optionally, the lock-in amplifier compares the received output signal with a reference signal and performs a difference calculation. If the relative phase value is not zero, the lock-in amplifier sends a frequency discrimination signal to the PID controller.
[0064] Optionally, the phase-locked amplifier and the optical signal detection device are electrically connected, and the TTL trigger pulse signal set in the phase-locked amplifier is sent to the trigger input end of the optical signal detection device, so that the reference signal of the phase-locked amplifier is synchronously triggered with the trigger signal of the optical signal detection device.
[0065] Optionally, the lock-in amplifier and the light source are electrically connected, frequency modulation is applied to the light source, and the frequency of the reference signal of the lock-in amplifier is set to be consistent with the laser modulation frequency of the light source.
[0066] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.
Claims
1. A phase stabilization system of an optical lattice, characterized in that: include: An optical lattice imaging assembly comprising an optical signal detection device, an optical assembly, and a light source, the optical assembly comprising a reflector, a prism group, and a lens group, the prism group being located between the light source and the reflector, the prism group comprising a first polarization beam splitting prism and a second polarization beam splitting prism, wherein a portion of light emitted by the light source passes through the first polarization beam splitting prism and is incident on the lens group and the optical signal detection device in sequence, and a portion of light passes through the reflector, and light reflected by the reflector passes through the second polarization beam splitting prism and is incident on the lens group and the optical signal detection device in sequence; An adjustment component, wherein the input end of the adjustment component is connected to the optical signal detection device, and the output end of the adjustment component has a brake, and the brake and the reflector are in transmission cooperation to adjust the distance between the reflector and the prism group to eliminate phase drift error, keep the one-dimensional optical lattice in a stable state, and achieve relative phase locking between light fields.
2. The phase stabilization system of an optical lattice according to claim 1, characterized in that: The regulating component includes a PID controller; The brake is a piezoelectric brake; The PID controller is electrically connected to the piezoelectric brake; The piezoelectric brake is connected to the reflector in a transmission manner to adjust the position of the reflector.
3. The phase stabilization system of the optical lattice according to claim 2, characterized in that: The regulating component includes a high voltage amplifier; An input end of the high-voltage amplifier is connected to the PID controller, and an output end of the high-voltage amplifier is electrically connected to the piezoelectric driver.
4. The phase stabilization system of an optical lattice according to claim 2, characterized in that: The regulating component includes a lock-in amplifier; The input end of the lock-in amplifier is connected to the optical signal detection device, and the output end of the lock-in amplifier is electrically connected to the PID controller.
5. The phase stabilization system of an optical lattice according to any one of claims 1 to 6, characterized in that: The optical signal detection device is an EMCCD device.
6. The phase stabilization method of the phase stabilization system of the optical lattice according to any one of claims 1 to 5, characterized in that: include: The regulating component obtains a frequency discrimination signal from an output signal of the optical signal detecting device; The adjustment component controls the brake to adjust the position of the reflector in the optical lattice imaging component according to the frequency discrimination signal to eliminate the phase drift error, keep the one-dimensional optical lattice in a stable state, and achieve relative phase locking between light fields.
7. The phase stabilization method of a one-dimensional optical lattice according to claim 6, characterized in that: The regulation components include a lock-in amplifier and a PID controller; The lock-in amplifier obtains a signal from the position with the largest slope in the traveling wave of the output signal as a frequency discrimination signal, and sends the frequency discrimination signal to the PID controller. The PID controller generates an output signal according to the frequency discrimination signal to control the brake to adjust the position of the reflector.
8. The phase stabilization method of a one-dimensional optical lattice according to claim 7, characterized in that: The lock-in amplifier compares the received output signal with the reference signal and takes the difference. If the relative phase value is not zero, the lock-in amplifier sends the frequency discrimination signal to the PID controller.
9. The phase stabilization method of a one-dimensional optical lattice according to claim 7, characterized in that: The lock-in amplifier and the optical signal detection device are electrically connected, and the TTL trigger pulse signal set in the lock-in amplifier is sent to the trigger input end of the optical signal detection device, so that the reference signal of the lock-in amplifier is synchronously triggered with the trigger signal of the optical signal detection device.
10. The phase stabilization method of a one-dimensional optical lattice according to claim 7, characterized in that: The lock-in amplifier is electrically connected to the light source, frequency modulation is applied to the light source, and the frequency of the reference signal of the lock-in amplifier is set to be consistent with the laser modulation frequency of the light source.