A phase-stabilized system of an optical lattice
By adjusting the components to monitor and adjust the position of the reflectors in real time, the problem of phase jitter in the optical lattice imaging components was solved, and the relative phase between the light fields was locked, thus improving the stability and accuracy of the experiment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANXI UNIV
- Filing Date
- 2025-07-03
- Publication Date
- 2026-07-31
AI Technical Summary
When an optical lattice imaging component is affected by external factors, slight displacement of some structural components can cause changes in optical path difference/arm length difference, resulting in phase jitter of the one-dimensional optical lattice and affecting the experimental results.
An adjustment component, including a lock-in amplifier, a PID controller, and a brake, is used. The phase difference is monitored in real time by an optical signal detection device. The lock-in amplifier and PID controller are used to precisely adjust the position of the reflector, eliminate phase drift error, and achieve locking of the relative phase between the light fields.
It effectively eliminates phase jitter, keeps the one-dimensional optical lattice in a stable state, ensures the locking of the relative phase between optical fields, and improves the stability and accuracy of the experiment.
Smart Images
Figure CN224581759U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of optical lattice imaging technology, and in particular to a phase stabilization system for an optical lattice. Background Technology
[0002] An optical lattice is a periodic potential well that appears in a standing wave field generated by the interference of multiple laser beams. The spatial period of the potential well is on the order of the laser wavelength, which can trap, cool, and confine atoms within the array of potential wells. Because the arrangement of atoms in such an array of potential wells is very similar to a "crystal structure" in solid-state physics, it is called an optical lattice. Optical lattices are an important research tool for experimentally simulating many-body systems, and also have significant applications in fields such as atomic clocks, manipulation of quantum states, study of coherent state properties, and quantum computing.
[0003] In related technologies, optical lattice imaging components include a light source, a mirror, and a lens group. Part of the light emitted from the light source passes through a prism group and directly enters the lens group, while another part passes through the mirror and is reflected before entering the lens group. Under external influences, some internal structural components of the optical lattice imaging component may undergo slight displacement, causing changes in the optical path difference / arm length difference between the two interfering light rays. This results in phase jitter in the one-dimensional optical lattice, affecting the experiment. Utility Model Content
[0004] To solve one of the above-mentioned technical problems, this utility model provides a phase stabilization system for an optical lattice.
[0005] The present invention adopts the following technical solution:
[0006] A phase-stabilized optical lattice system, comprising:
[0007] An optical lattice imaging assembly includes a main light source, a reflector, a lens group, and a light signal detection device. Part of the light emitted from the main light source passes through the lens group and is then incident on the light signal detection device, while part of it passes through the reflector. The light reflected by the reflector passes through the lens group and is then incident on the light signal detection device.
[0008] An adjustment component is provided, the input end of which is connected to the optical signal detection device, and the output end of which has a brake. The brake and the reflector are driven together to adjust the distance between the reflector and the light source.
[0009] Optionally, the adjustment component includes a lock-in amplifier and a linear controller;
[0010] The input terminal of the lock-in amplifier is electrically connected to the optical signal detection device, the output terminal of the lock-in amplifier is electrically connected to the linear controller, and the linear controller is electrically connected to the brake.
[0011] Optionally, the linear controller is a PID controller.
[0012] Optionally, the phase stabilization system includes a high-voltage amplifier;
[0013] The input terminal of the high-voltage amplifier is connected to the linear controller, and the output terminal of the high-voltage amplifier is electrically connected to the brake.
[0014] Optionally, the lock-in amplifier and the optical signal detection device are connected via a BNC to SMA cable.
[0015] Optionally, the lock-in amplifier and the light source are connected via a BNC cable.
[0016] Optionally, the optical signal detection device is an EMCCD device.
[0017] Optionally, the brake is a piezoelectric actuator.
[0018] Optionally, the optical lattice imaging component includes a first polarizing beam splitter and a second polarizing beam splitter;
[0019] The reflector, the second polarizing beam splitter, the first polarizing beam splitter, and the light source are arranged sequentially along a straight line.
[0020] Part of the light emitted by the light source passes through the first prism and is sequentially incident on the lens group and the light signal detection device, while part of the light passes through the reflector. The light reflected by the reflector passes through the second prism and is sequentially incident on the lens group and the light signal detection device.
[0021] Optionally, the optical lattice imaging component includes a quarter-wave plate and a half-wave plate;
[0022] The half-wave plate is located between the light source and the first polarizing beam splitter prism, and the quarter-wave plate is located between the second polarizing beam splitter prism and the reflector.
[0023] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings. Attached Figure Description
[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are merely some embodiments; those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:
[0025] Figure 1 A schematic diagram of a phase-stabilized optical lattice system provided in an embodiment of this disclosure is shown.
[0026] Figure 2 A block diagram of the phase stabilization system of an optical lattice provided in an embodiment of this disclosure is shown.
[0027] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate this utility model, but are not intended to limit the scope of this utility model.
[0029] In the description of this utility model, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0031] An optical lattice is a periodic potential well that appears in a standing wave field generated by the interference of multiple laser beams. The spatial period of the potential well is on the order of the laser wavelength, which can trap, cool, and confine atoms within the array of potential wells. Because the arrangement of atoms in such an array of potential wells is very similar to a "crystal structure" in solid-state physics, it is called an optical lattice. Optical lattices are an important research tool for experimentally simulating many-body systems, and also have significant applications in fields such as atomic clocks, manipulation of quantum states, study of coherent state properties, and quantum computing.
[0032] like Figure 1 and Figure 2As shown in the illustration, this 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 includes a main light source, a reflector, a lens group, and a light signal detection device. Part of the light emitted from the main light source passes through the lens group and is incident on the light signal detection device, while part passes through the reflector. The light reflected by the reflector passes through the lens group and is incident on the light signal detection device. The input end of the adjustment component is connected to the light signal detection device, and the output end of the adjustment component has a brake. The brake and the reflector are in a driving engagement to adjust the distance between the reflector and the light source. This eliminates phase drift errors, keeps the one-dimensional optical lattice in a stable state, and achieves phase locking between the light fields.
[0033] The light source can be a laser source. The optical lattice imaging component includes a prism group located between the light source and a reflector. The prism group includes a first polarizing beam-splitting prism and a second polarizing beam-splitting prism. Part of the light emitted by the light source passes through the first polarizing beam-splitting prism and is subsequently incident on the lens group and the optical signal detection device (as shown in the EMCCD device). Part of the light passes through the reflector, which can be a total internal reflection mirror, perpendicular to the light emission direction of the light source. The light reflected by the reflector passes through the second polarizing beam-splitting prism and is subsequently incident on the lens group and the optical signal detection device. 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 a driving engagement to adjust the distance between the reflector and the prism group, thereby eliminating phase drift errors and maintaining the one-dimensional optical lattice in a stable state, achieving phase locking between the light fields.
[0034] In this application, an 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 beams. Experiments show that under external influences, changes in the optical path difference / arm length difference between the two interfering beams can easily occur, leading to phase jitter in the one-dimensional optical lattice. This application compensates for the phase difference and eliminates phase drift error by adjusting the component design, keeping the one-dimensional optical lattice in a stable state and achieving phase locking between the optical fields.
[0035] like Figure 2 As shown, the prism group of the optical lattice imaging component includes a first polarizing beam splitter and a second polarizing beam splitter. A reflector, the second polarizing beam splitter, the first polarizing beam splitter, and the light source are arranged sequentially along a straight line, with the first and second polarizing beam splitters symmetrically positioned. Part of the light emitted by the light source passes through the first polarizing beam splitter and is subsequently incident on the lens group and the optical signal detection device. Part of the light passes through the reflector, and the light reflected by the reflector passes through the second polarizing beam splitter and is subsequently incident on the lens group and the optical signal detection device.
[0036] In some possible implementations, the optical lattice imaging assembly includes a quarter-wave plate and a half-wave plate, the half-wave plate being located between the light source and a first polarizing beam splitter prism, and the quarter-wave plate being located between a second polarizing beam splitter prism and a reflector.
[0037] A half-wave plate is an optical element that alters the polarization state of light using a birefringent material. Its core function is to introduce a π-phase difference into linearly polarized light, rotating its polarization direction by a specific angle. This application incorporates a half-wave plate before beam splitting to ensure consistent light polarization. A quarter-wave plate is used to introduce a phase delay of π / 2, enabling the conversion between linearly polarized, circularly polarized, and elliptically polarized light.
[0038] The lens group may include a first lens, a second lens, and a third lens. The prism group, the first lens, the second lens, the third lens, and the optical signal detection device are arranged sequentially. Two beams of light emitted from the light source ultimately pass through the first lens, the second lens, and the third lens in sequence before entering the optical signal detection device. The two beams are split by a polarizing beam-splitting prism and then combined between the first and second lenses. Interference occurs at the beam intersection point, forming a one-dimensional optical lattice. The light then passes through the second and third lenses before entering the optical signal detection device.
[0039] Optical signal detection devices can be photodetectors and oscilloscopes, or they can be EMCCD devices, which can monitor a one-dimensional optical lattice through the real-time incident optical signal. The movement of the interference fringes reflects the relative change in the length displacement of the interference arms.
[0040] In some possible implementations, the regulating components include a PID controller (a specific example of a linear 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 kinetically connected to adjust the position of the reflector.
[0041] 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 research and industrial applications. The basic principle of PID control is: the PID controller calculates the error (e(t) = target value - current value), where the target value is the theoretical value under normal conditions, and the current value is the frequency discrimination signal sent to the PID controller in real time. It then adjusts the control quantity (u(t)) to stabilize the system at the target value. Its mathematical expression is:
[0042]
[0043] Where 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 derivative gain (suppresses overshoot and enhances stability).
[0044] The brake is a piezoelectric brake, such as a piezoelectric ceramic. By changing the operating voltage of the piezoelectric ceramic to compensate for this displacement, the stripes of the optical signal detection device can be moved in the opposite direction and restored to the equilibrium position.
[0045] In some possible implementations, the regulating component includes a high-voltage amplifier, the input of which is connected to the PID controller, and the output of which is electrically connected to the piezoelectric actuator. The high-voltage amplifier is capable of boosting the input signal to the required high-voltage range, thereby driving the brake movement.
[0046] In some possible implementations, the phase stabilization system of the optical lattice includes a lock-in amplifier, the input of which is connected to the optical signal detection device, and the output of which is electrically connected to the linear controller, such as a PID controller.
[0047] The lock-in amplifier (LIP), model SR830, is an experimental device for weak signal detection. It extracts the signal with the same frequency and phase characteristics as the reference signal by comparing it with a reference input signal. Similar to an analog correlator, it uses the lack of correlation between the 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 uses a low-noise differentiating amplifier and a band-stop filter for signal amplification and noise reduction, filtering out higher-order terms and additional noise. The reference channel provides a frequency reference signal. The LIP operates based on Fourier transform; its output is a DC voltage signal proportional to the amplitude of the input signal with the same frequency and phase information as the reference signal. Other frequency components in the input signal have no effect on the output signal of the LIP.
[0048] The optical signal detection device converts the optical signal into an electrical signal and sends it to a lock-in amplifier (LPA). The LPA uses the two points with the largest slopes in the traveling wave of the electrical signal (or optical signal) as frequency discrimination signals and feeds them back to the PID controller. The PID controller is a real-time sampling linear controller. We use it to perform proportional-integral calculations on the error signal, and reduce the error by comparing the input error signal and the output control signal in real time. When the interference fringes change, i.e., there is a phase drift, the optical signal detection device converts the received optical signal into a voltage signal and transmits it to the LPA. The LPA compares the input signal received with the reference signal and calculates the difference. If the relative phase value is not zero, the output signal of the LPA is fed back to the PID controller. The feedback signal is finally amplified by high voltage and controls the piezoelectric ceramic (actuator) to extend and retract, driving it to adjust the position of the 0° total reflection mirror with nanometer-level precision. The above feedback compensates for the phase difference and eliminates the phase drift error, keeping the one-dimensional optical lattice in a stable state and achieving phase locking between the optical fields.
[0049] In some possible implementations, the optical signal detection device can be an EMCCD device, such as the IXon Ultra888. The EMCCD device replaces the traditional optical signal detection device to observe changes in interference fringes. When using a traditional optical signal detection device, the diameters of the two interference beams are too small, the spot size is smaller than the detection area of the optical signal detection device, and the two beams have a certain angle, making it difficult to accurately determine the position of the optical lattice formed by the interference. Furthermore, after the optical signal detection device is connected to an oscilloscope, it is impossible to demodulate the optical signal based on the obtained voltage signal curve. This application uses an EMCCD device, which allows direct observation of the optical lattice image formed by the interference. Moreover, when adjusting the alignment of the two interference beams, the image captured by the EMCCD device can be used as a reference, greatly reducing the difficulty of adjusting the alignment of the interference beams.
[0050] In some possible implementations, the lock-in amplifier and the optical signal detection device are connected via a BNC-to-SMA cable. The BNC-to-SMA cable connects the lock-in amplifier to the EMCCD device, allowing the pre-set TTL trigger pulse signal from the lock-in amplifier to be connected to the external trigger input of the EMCCD. This ensures that the reference signal of the lock-in amplifier is triggered synchronously with the trigger signal of the EMCCD, i.e., the EMCCD device is triggered to capture the optical lattice at the rising (or falling) edge of the signal. This guarantees that the exposure time of the EMCCD device is synchronized with the demodulation signal time of the lock-in amplifier.
[0051] In some possible implementations, the lock-in amplifier and the light source are connected via a BNC cable. Frequency modulation is applied to the laser light source through the lock-in amplifier. The reference frequency of the internal reference signal terminal of the lock-in amplifier is set to match the laser modulation frequency (e.g., both are set to 5kHz), and the lock-in amplifier and laser are connected via a BNC cable. The lock-in amplifier is then used to apply frequency modulation to the optical signal.
[0052] It should be noted that the modulation method for optical signals is not limited to lock-in amplifiers; intensity modulation or frequency modulation can also be applied to optical signals through external devices such as AOM and EOM.
[0053] Example 2
[0054] Embodiment 2 of this application provides a phase stabilization method for the above-mentioned optical lattice phase stabilization system, including:
[0055] The adjustment component obtains the frequency discrimination signal from the output signal of the optical signal detection device;
[0056] In this step, a lock-in amplifier is mainly used to obtain a frequency discrimination signal from the numerous signals in the output signal. The lock-in amplifier extracts the signal with the same frequency and phase characteristics as the reference signal from the output signal of the optical signal detection device by comparing it with the reference input signal. The reference signal can be a set value based on the actual situation.
[0057] The adjustment component controls the actuator to adjust the position of the mirror in the optical lattice imaging component according to the frequency discrimination signal, so as to eliminate phase drift error, keep the one-dimensional optical lattice in a stable state, and realize the locking of the relative phase between the light fields.
[0058] The regulating components include a lock-in amplifier and a PID controller;
[0059] The lock-in amplifier obtains the signal from the position with the largest slope in the traveling wave of the output signal as the frequency discrimination signal, and sends the frequency discrimination signal to the PID controller. The PID controller generates an output signal based on the frequency discrimination signal to control the brake to adjust the position of the reflector.
[0060] Optionally, the lock-in amplifier compares the received output signal with the reference signal and calculates the difference. If the relative phase value is not zero, the lock-in amplifier sends the frequency discrimination signal to the PID controller.
[0061] Optionally, 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 terminal of the optical signal detection device, so that the reference signal of the lock-in amplifier is triggered synchronously with the trigger signal of the optical signal detection device.
[0062] Optionally, 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.
[0063] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.
Claims
1. A phase stabilization system for an optical lattice, characterized by, include: An optical lattice imaging assembly includes a main light source, a reflector, a lens group, and a light signal detection device. Part of the light emitted from the main light source passes through the lens group and is then incident on the light signal detection device, while part of it passes through the reflector. The light reflected by the reflector passes through the lens group and is then incident on the light signal detection device. An adjustment component is provided, the input end of which is connected to the optical signal detection device, and the output end of which has a brake. The brake and the reflector are driven together to adjust the distance between the reflector and the light source.
2. The phase stabilisation system of an optical lattice according to claim 1, wherein, The adjustment components include a lock-in amplifier and a linear controller; The input terminal of the lock-in amplifier is electrically connected to the optical signal detection device, the output terminal of the lock-in amplifier is electrically connected to the linear controller, and the linear controller is electrically connected to the brake.
3. The phase stabilisation system of an optical lattice according to claim 2, wherein, The linear controller is a PID controller.
4. The phase stabilisation system of an optical lattice according to claim 2, wherein, The regulating component includes a high-voltage amplifier; The input terminal of the high-voltage amplifier is connected to the linear controller, and the output terminal of the high-voltage amplifier is electrically connected to the brake.
5. The phase-stabilized optical lattice system according to claim 2, characterized in that, The lock-in amplifier and the optical signal detection device are connected via a BNC to SMA cable.
6. The phase stabilizing system of an optical lattice according to claim 2, wherein, The lock-in amplifier and the light source are connected via a BNC cable.
7. The phase stabilizing system of an optical lattice according to claim 1, wherein, The optical signal detection device is an EMCCD device.
8. The phase stabilizing system of an optical lattice according to claim 1, wherein, The brake is a piezoelectric actuator.
9. The phase-stabilized system of an optical lattice according to any one of claims 1-8, characterized in that, The optical lattice imaging component includes a first polarizing beam splitter and a second polarizing beam splitter. The reflector, the second polarizing beam splitter, the first polarizing beam splitter, and the light source are arranged sequentially along a straight line. Part of the light emitted by the light source passes through the first prism and is sequentially incident on the lens group and the light signal detection device, while part of the light passes through the reflector. The light reflected by the reflector passes through the second prism and is sequentially incident on the lens group and the light signal detection device.
10. The phase-stabilized optical lattice system according to claim 9, characterized in that, The optical lattice imaging component includes a quarter-wave plate and a half-wave plate; The half-wave plate is located between the light source and the first polarizing beam splitter prism, and the quarter-wave plate is located between the second polarizing beam splitter prism and the reflector.