Laser frequency stabilization device and method

Abstract

The application discloses a laser frequency stabilizing device and method. The device comprises a saturated absorption spectrum frequency stabilizing component and an ultrastable cavity frequency stabilizing component. The saturated absorption spectrum frequency stabilizing component is connected with a first to-be-locked laser, and a laser emitted by the first to-be-locked laser is processed to obtain a first locking signal and a correction signal. The first locking signal is injected into the first to-be-locked laser to lock the frequency of the first to-be-locked laser. The correction signal is injected into an ultrastable cavity in the ultrastable cavity frequency stabilizing component to correct the cavity length of the ultrastable cavity. The ultrastable cavity frequency stabilizing component is connected with a second to-be-locked laser, and a laser emitted by the second to-be-locked laser is processed to obtain a second locking signal. The second locking signal is injected into the second to-be-locked laser to lock the frequency of the second to-be-locked laser. The embodiment of the application can simultaneously lock the frequencies of multiple lasers, has low cost and simple overall structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of quantum computers, and in particular to a laser frequency stabilization device and method for ion trap quantum computers. BACKGROUND

[0002] Lasers play a vital role in many fields, especially in the field of quantum technology applications. In some application scenarios, such as but not limited to ion trap quantum computers, multiple lasers need to work simultaneously for a long time. As one of the three functional components of a laser, a resonant cavity is easily affected by the external environment in practical applications, resulting in changes in the cavity length. Changes in the cavity length of the resonant cavity will cause the frequency of the laser to drift, which will affect the application effect in the scene. SUMMARY

[0003] Therefore, the embodiments of the present application provide a laser frequency stabilization device and method to solve the technical problems of high cost and complex structure when multiple lasers are stabilized simultaneously.

[0004] In order to solve the above technical problems, according to one aspect of the present application, a laser frequency stabilization device is provided, comprising a saturated absorption spectrum frequency stabilization component and a super-stable cavity frequency stabilization component; wherein the saturated absorption spectrum frequency stabilization component is connected with a first to-be-locked laser, and processes the laser emitted by the first to-be-locked laser to obtain a first locking signal and a correction signal; the first locking signal is injected into the first to-be-locked laser to lock the frequency of the first to-be-locked laser; the correction signal is injected into a super-stable cavity in the super-stable cavity frequency stabilization component to correct the cavity length of the super-stable cavity; the super-stable cavity frequency stabilization component is connected with a second to-be-locked laser, and processes the laser emitted by the second to-be-locked laser to obtain a second locking signal; and the second locking signal is injected into the second to-be-locked laser to lock the frequency of the second to-be-locked laser.

[0005] In order to solve the above technical problems, according to another aspect of the present application, a laser frequency stabilization method based on the aforementioned laser frequency stabilization device is provided, comprising the following steps: processing the laser emitted by the first to-be-locked laser through the saturated absorption spectrum frequency stabilization component to obtain a first locking signal and a correction signal; injecting the first locking signal into the first to-be-locked laser to lock the frequency of the first to-be-locked laser; injecting the correction signal into the super-stable cavity to correct the cavity length of the super-stable cavity; processing the laser emitted by the second to-be-locked laser through the super-stable cavity frequency stabilization component to obtain a second locking signal; and injecting the second locking signal into the second to-be-locked laser to lock the frequency of the second to-be-locked laser.

[0006] The application selects the atomic or molecular matched with the energy level of the first laser to be locked as the gas chamber gas in the atomic and molecular saturated absorption according to the wavelength of the first laser to be locked, so that the first laser to be locked can be stabilized for a long time; the super stable cavity is corrected by the locking signal of the long time stabilization of the first laser to be locked, so that the super stable cavity can keep the stability of the cavity length for a long time, so that it becomes the frequency standard source of the stabilization of the second laser to be locked. Since the super stable cavity stabilization method has no requirement on the frequency of the laser to be locked, the application can simultaneously stabilize multiple lasers with different frequencies for a long time.

[0007] In order to solve the above technical problems, according to another aspect of the application, the application provides a laser stabilization device, comprising a first beam splitting assembly, a saturated absorption spectrum stabilization assembly and a beat frequency stabilization assembly, wherein the incident end of the first beam splitting assembly is connected to the laser output end of the first laser to be locked, and the laser emitted by the first laser to be locked is split into a first laser and a second laser; the first laser is delivered to the saturated absorption spectrum stabilization assembly, and the second laser is delivered to the beat frequency stabilization assembly; the saturated absorption spectrum stabilization assembly is connected to the first beam splitting assembly, and the first laser emitted by the first laser to be locked is processed by the saturated absorption spectrum stabilization assembly to obtain a first locking signal; the first locking signal is injected into the first laser to be locked to lock the frequency of the first laser to be locked; the beat frequency stabilization assembly is connected to the second laser to be locked and the first beam splitting assembly respectively, and the laser emitted by the second laser to be locked and the second laser emitted by the first laser to be locked are processed by the beat frequency stabilization assembly to obtain a second locking signal; the second locking signal is injected into the second laser to be locked to lock the frequency of the second laser to be locked; wherein the wavelength of the second laser to be locked is the same as the wavelength of the first laser to be locked.

[0008] In order to solve the above technical problems, according to another aspect of the application, the application provides a laser stabilization method based on the foregoing laser stabilization device, comprising the following steps: splitting the laser emitted by the first laser to be locked into a first laser and a second laser; processing the first laser by the saturated absorption spectrum stabilization assembly to obtain a first locking signal; injecting the first locking signal into the first laser to be locked to lock the frequency of the first laser to be locked; sending the laser emitted by the second laser to be locked and the second laser to the beat frequency stabilization assembly, and processing by the beat frequency stabilization assembly to obtain a second locking signal; wherein the wavelength of the second laser to be locked is the same as the wavelength of the first laser to be locked; and injecting the second locking signal into the second laser to be locked to lock the frequency of the second laser to be locked.

[0009] The application selects the atomic or molecular matched with the energy level of the first laser to be locked as the gas chamber gas in the atomic and molecular saturated absorption according to the wavelength of the first laser to be locked, so that the first laser to be locked can be stabilized for a long time; the first laser to be locked is used as the frequency standard source to stabilize the frequency of other lasers with the same wavelength, so that the application can simultaneously stabilize the frequency of multiple lasers with the same wavelength for a long time. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following briefly introduces the drawings in the embodiments of the application.

[0011] Figure 1 is a principle block diagram of a laser frequency stabilization device according to an embodiment of the application.

[0012] Figure 2 is a structural schematic diagram of a laser frequency stabilization device according to an embodiment of the application.

[0013] Figure 3 is a frequency stabilization method flowchart based on the laser frequency stabilization device shown in Figure 2 .

[0014] Figure 4 is a structural schematic diagram of a laser frequency stabilization device according to another embodiment of the application.

[0015] Figure 5 is a frequency stabilization method flowchart based on the laser frequency stabilization device shown in Figure 4 .

[0016] Figure 6 is a structural schematic diagram of a laser frequency stabilization device according to another embodiment of the application.

[0017] Figure 7 is a frequency stabilization method flowchart based on the laser frequency stabilization device shown in Figure 6 . DETAILED DESCRIPTION

[0018] The main idea of the application is to select a stable frequency standard source as a reference signal, compare the frequency to be stabilized with the frequency of the standard source, obtain an error signal of the frequency offset of the two, convert the error signal into an electrical signal, and feed back the electrical signal to the piezoelectric ceramic in the internal resonant cavity of the laser in real time, so as to control the length of the resonant cavity and finally realize the stabilization of the laser frequency.

[0019] The application provides a laser frequency stabilization device and method for an ion trap quantum computer, which realizes the stabilization of the laser of multiple lasers at the same time. Figure 1is a principle block diagram of a laser frequency stabilization device according to an embodiment of the present application. In the embodiment, two lasers to be locked are shown in the figure: a laser to be locked 10 and a laser to be locked 20. The laser frequency stabilization device provided by the present application comprises a saturated absorption spectrum frequency stabilization component 100 and a super stable cavity frequency stabilization component 200. The saturated absorption spectrum frequency stabilization component 100 comprises a light input end 101, a locking signal end 102 and a correction signal end 103. The super stable cavity frequency stabilization component 200 comprises a light input end 201, a locking signal end 202 and a correction signal end 203. The super stable cavity frequency stabilization component 200 can comprise a plurality of light input ends 201 and corresponding locking signal ends 202 for locking the frequency of a plurality of lasers. For simplicity of description and the figure, two lasers are taken as an example for description in the embodiment.

[0020] The laser to be locked 10 has a laser output end 11 for frequency stabilization, a frequency locking end 12 and a main laser output end (not shown in the figure). For example, the laser generated by the laser to be locked 10 passes through an optical isolator, a half wave plate and a PBS (Polarization Beam Splitter) in an internal optical path, and the transmitted light is taken as the main laser output, and the reflected light is output to the saturated absorption spectrum frequency stabilization component 100 through the laser output end 11. The frequency locking end 12 is electrically connected to the piezoelectric ceramic of the internal resonant cavity of the laser to be locked 10, and when an electrical signal acts on the piezoelectric ceramic of the resonant cavity, the cavity length of the resonant cavity is changed according to the size of the electrical signal, so as to change the laser frequency of the laser to be locked 10.

[0021] The laser to be locked 20 has the same structure as the laser to be locked 10, and will not be described here. The laser output end 21 of the laser to be locked 20 is connected to the light input end 201 of the super stable cavity frequency stabilization component 200, and the laser of the laser to be locked 20 is sent to the super stable cavity frequency stabilization component 200.

[0022] The laser of the laser to be locked 10 is output to the light input end 101 of the saturated absorption spectrum frequency stabilization component 100 through the laser output end 11, and the locking signal and the correction signal are obtained after the processing of the saturated absorption spectrum frequency stabilization component 100. The locking signal end 102 is connected to the frequency locking end 12 of the laser to be locked 10, and the laser to be locked is frequency-locked by the locking signal.

[0023] The correction signal end 103 of the saturated absorption spectrum frequency stabilization component 100 is connected with the correction signal end 203 of the super stable cavity frequency stabilization component 200, the correction signal generated by the saturated absorption spectrum frequency stabilization component 100 is an electric signal, and is sent to the super stable cavity frequency stabilization component 200. The correction signal end 203 is electrically connected with the piezoelectric ceramic of the super stable cavity in the super stable cavity frequency stabilization component 200, when the correction signal acts on the piezoelectric ceramic of the super stable cavity, the cavity length of the super stable cavity is changed according to the size of the electric signal, so that the cavity length of the super stable cavity is kept unchanged, and the defect that the cavity length of the super stable cavity is changed due to long time working is overcome.

[0024] According to the wavelength of the laser to be locked 10, the atomic or molecular matched with the energy level is selected as the gas chamber gas in the atomic and molecular saturated absorption, so that the laser to be locked 10 can be stabilized for a long time; the cavity length of the super stable cavity is corrected by the locking signal of the laser to be locked 10, so that the super stable cavity can keep the stability of the cavity length for a long time, and becomes the frequency standard source of the laser to be locked 20. Since the super stable cavity has no requirement on the frequency of the laser to be locked, the laser to be locked of different frequencies can be stabilized for a long time at the same time.

[0025] Figure 2 It is a structure schematic diagram of the laser frequency stabilization device according to an embodiment of the present application, the thick line in the figure represents the optical path, and the thin line represents the electric signal path. In the embodiment, the saturated absorption spectrum frequency stabilization component 100 includes a beam splitting component 110, an atomic and molecular gas chamber 120, a photodetector 130, a reference signal source 140, a phase-locked amplifier 150, a PID controller 160 and a power divider 170.

[0026] The beam splitting component 110 includes a half-wave plate, a PBS and a mirror, wherein the incident end of the half-wave plate is connected with the laser to be locked 10, and the outgoing end is connected with the PBS. The laser emitted by the laser to be locked 10 passes through the half-wave plate and the PBS in sequence, and the polarization direction of the laser emitted by the laser to be locked 10 is processed into the polarization component O light perpendicular to the optical axis and the polarization component e light parallel to the optical axis. And the PBS splits the laser into the pump light with larger intensity and the probe light with weaker intensity, which are incident to the atomic and molecular gas chamber 120 through the pump light path and the probe light path respectively. In the embodiment, the probe light path includes a mirror, and the probe light is incident to the atomic and molecular gas chamber 120 through the mirror. The pump light path includes a mirror, and the pump light is incident to the atomic and molecular gas chamber 120 from the opposite direction through the mirror, and the pump light and the probe light generate the saturated absorption spectrum signal in the atomic and molecular gas chamber 120. In the embodiment, the pump light path further includes an optional acousto-optic modulator AOM, the pump light is modulated by the acousto-optic modulator AOM, and the modulated pump light is incident to the atomic and molecular gas chamber 120 to generate the saturated absorption spectrum signal with the probe light.

[0027] The saturated absorption spectrum signal generated by the atomic and molecular gas chamber 120 carries the modulated frequency or phase information, which is converted into an electric signal by the photoelectric detector 130 and sent to the phase-locked amplifier 150. The electric signal includes the modulated frequency information. In this embodiment, a PBS and a mirror are added in the light path between the atomic and molecular gas chamber 120 and the photoelectric detector 130 to change the direction of the light, which is an optional component and depends on the actual layout of the components.

[0028] The reference signal source 140 simultaneously provides reference signals for the acousto-optic modulator AOM and the phase-locked amplifier 150.

[0029] The phase-locked amplifier 150 processes the electric signal of the absorption spectrum signal sent by the photoelectric detector 130 and the reference signal to demodulate the frequency or phase shift signal, i.e., the error signal, and then sends the error signal to the PID controller 160. After proportional, integral, and differential calculation, the lock signal is obtained. The lock signal calculated by the PID controller 160 in this embodiment is divided into a lock signal and a correction signal by the power divider 170. The lock signal is injected into the to-be-locked laser 10 to lock the frequency of the to-be-locked laser 10. The correction signal is injected into the ultra-stable cavity 210 in the ultra-stable cavity frequency stabilization assembly 200 to correct the cavity length of the ultra-stable cavity 210.

[0030] The ultra-stable cavity frequency stabilization assembly 200 includes an ultra-stable cavity 210, a photoelectric detector 220, a reference signal source 230, a phase-locked amplifier 240, and a PID controller 250.

[0031] The to-be-locked laser 20 is connected to the ultra-stable cavity 210 through an incident light path. Optionally, an electro-optic modulator EOM is added in the incident light path to modulate the frequency or phase of the laser incident to the ultra-stable cavity 210. The reflected light of the ultra-stable cavity 210 is sent to the photoelectric detector 220 to obtain an electric signal of the reflected light. According to the need, a 1 / 4 wave plate and a PBS can be added in the reflected light path between the ultra-stable cavity 210 and the photoelectric detector 220 to isolate the reflected light by the 1 / 4 wave plate and change the deflection direction of the reflected light of the ultra-stable cavity 210 by the PBS to send the reflected light of the ultra-stable cavity 210 to the photoelectric detector 220.

[0032] The reflected light of the ultra-stable cavity 210 contains the frequency or phase information modulated by the electro-optic modulator EOM, and the same information is retained in the electric signal after conversion by the photoelectric detector 220.

[0033] The reference signal source 230 simultaneously provides reference signals for the electro-optic modulator EOM and the phase-locked amplifier 240.

[0034] The phase-locked amplifier 240 processes the electrical signal of the reflected signal sent by the photoelectric detector 220 and the reference signal, demodulates the frequency offset electrical signal or the phase offset electrical signal, that is, the error signal. The error signal is sent to the PID controller 250, and the locking signal is obtained after proportional, integral and differential calculation. The locking signal is injected into the laser to be locked 20 to lock the frequency of the laser to be locked 20.

[0035] The laser to be locked 20 in the embodiment can be multiple. When there are multiple lasers to be locked 20, there are corresponding multiple photoelectric detectors 220, reference signal sources 230, phase-locked amplifiers 240 and PID controllers 250, and the standard signal is provided based on the same super stable cavity 210, so that the purpose of simultaneously locking the frequency of multiple lasers can be achieved.

[0036] Figure 3 The laser frequency stabilization device shown in FIG. 1 is based on Figure 2 The frequency stabilization method flow chart of the laser frequency stabilization device is shown in FIG. 2, and the method comprises the following steps:

[0037] In step S110a, the laser emitted by the laser to be locked 10 is processed by the saturated absorption spectrum frequency stabilization assembly 100 to obtain the locking signal and the correction signal.

[0038] In step S120a, the locking signal obtained in step S110a is injected into the laser to be locked 10 to lock the frequency of the laser to be locked 10, and the correction signal obtained in step S110a is injected into the super stable cavity 210 to correct the cavity length of the super stable cavity 210.

[0039] In step S130a, the laser emitted by the laser to be locked 20 is processed by the super stable cavity frequency stabilization assembly to obtain the locking signal.

[0040] In step S140a, the locking signal obtained in step S130a is injected into the laser to be locked 20 to lock the frequency of the laser to be locked 20.

[0041] The super-stable cavity 210 in this embodiment can be a Fabry-Perot cavity (FP cavity for short), which is a commonly used reference cavity in the industry and is composed of two high-reflective plane mirrors. Since the FP cavity can provide an accurate standard signal in a short time, using the reflected light signal of the FP cavity as the standard signal for frequency locking can achieve good frequency locking effect for the laser in a short time. However, the cavity length of the FP cavity is easily disturbed by the outside environment and changes, and once the cavity length changes, the reflected light signal is no longer accurate, so the FP cavity cannot be used for frequency locking for a long time in the conventional frequency locking technology. However, in the present application, the saturated absorption spectrum frequency stabilization assembly 100 can provide a correction signal for correcting the cavity length of the FP cavity to the FP cavity in real time when the FP cavity is working, so as to maintain the stability of the cavity length of the FP cavity. In other words, even if the external environment changes over time, the cavity length of the FP cavity can be consistent over time, which can effectively improve the precision control of the cavity length of the FP cavity, and thus the FP cavity can always provide an accurate standard signal, achieving the purpose of long-term frequency stabilization for the laser.

[0042] Figure 4 is a schematic diagram of the structure of a laser frequency stabilization device according to another embodiment of the present application. Compared with Figure 2The laser frequency stabilization device also comprises a beam splitting assembly 109, the incident end of which is connected to the laser to be locked 10, and the laser emitted by the laser to be locked 10 is split into two beams, one of which is incident on the beam splitting assembly 110 in the saturated absorption spectrum frequency stabilization assembly 100 via an optical path; the other beam is incident on the super stable cavity 210 in the super stable cavity frequency stabilization assembly 200 via a super stable cavity optical path. Some optical path elements are included in the super stable cavity optical path, such as a 1 / 2 wave plate, a PBS and a 1 / 4 wave plate. The reflected light of the other beam of the two beams is sent to the photodetector 201 through the 1 / 4 wave plate and the PBS, which is converted into an electrical signal by the photodetector 201 and sent to the phase-locked amplifier 202. The phase-locked amplifier 202 processes the electrical signal of the reflected signal sent by the photodetector 201 and the reference signal from the reference signal source 203 to obtain an error signal, and then sends the error signal to the PID controller 204 to obtain a locking signal after proportional, integral and differential calculation, which is injected into the laser to be locked 10 and simultaneously locks the frequency of the laser to be locked 10 with the locking signal obtained by the saturated absorption spectrum frequency stabilization assembly 100. The reference signal source 203 and the reference signal source 230 can be a reference signal source or different reference signal sources. Moreover, an electro-optic modulator EOM (not shown in the figure) can be included in the super stable cavity optical path in the super stable cavity 210 to perform frequency modulation, which is used to obtain a more stable locking signal. In addition, in order to increase the power of the correction signal for correcting the super stable cavity 210, a power amplifier 180 can be added to the circuit to meet the requirements of the piezoelectric ceramic of the super stable cavity for electrical signals.

[0043] Correspondingly, Figure 5 is based on Figure 4 The laser frequency stabilization device performs a frequency stabilization method on the laser to be locked 10, and the method comprises the following steps:

[0044] Step S110b, splitting the laser emitted by the laser to be locked 10 into two beams.

[0045] Step S120b, one of the two beams is incident on the saturated absorption spectrum frequency stabilization assembly 100 to obtain a locking signal.

[0046] Step S130b, the locking signal is injected into the laser to be locked 10 to lock the frequency of the laser to be locked 10.

[0047] Step S140b, the other beam of the two beams is incident on the super stable cavity frequency stabilization assembly 200 to obtain another locking signal via the super stable cavity frequency stabilization assembly 200.

[0048] Step S150b, another locking signal is injected into the to-be-locked laser 10 to lock the to-be-locked laser 10 together with the locking signal obtained from the saturated absorption spectrum frequency stabilization assembly 100.

[0049] In this embodiment, two locking signals obtained from the super-stable cavity frequency stabilization assembly 200 and the saturated absorption spectrum frequency stabilization assembly 100 are used to stabilize the frequency of the to-be-locked laser 10.

[0050] Figure 6 is a schematic diagram of a laser frequency stabilization device structure according to another embodiment of the present application. Compared with the device shown in Figure 4 Compared with the device shown in the embodiment, the present embodiment further provides a beam splitting assembly 108 and a beat frequency frequency stabilization assembly 300. The beat frequency frequency stabilization assembly 300 comprises a beam combining assembly 310, a photodetector 320, a reference signal source 330, a phase-locked amplifier 340 and a PID controller 350; the beam combining assembly 310 is, for example, a PBS, and the incident end of the beam splitting assembly 108 is connected to the to-be-locked laser 10 to split the laser emitted by the to-be-locked laser 10 into two beams. One of the two beams is incident to the beam combining assembly 310 together with the laser emitted by the to-be-locked laser 30 to be combined in the beam combining assembly 310 and to obtain a beat frequency interference optical signal. The beat frequency interference optical signal is converted into an electrical signal by the photodetector 320, and the electrical signal and a reference signal provided by the reference signal source 330 are used to obtain a beat frequency offset signal by the phase-locked amplifier 340. The beat frequency offset signal is used to obtain a locking signal by the PID controller 350; the locking signal is injected into the to-be-locked laser 30 to lock the frequency of the to-be-locked laser 30. Another beam obtained by splitting in the beam splitting assembly 108 is split into two beams by the beam splitting assembly 109, and the two beams are used to obtain two locking signals by the saturated absorption spectrum frequency stabilization assembly 100 and the super-stable cavity frequency stabilization assembly 200 to lock the to-be-locked laser 10 together. In this embodiment, the wavelength of the to-be-locked laser 30 is the same as that of the to-be-locked laser 10, and the laser of the to-be-locked laser 10 is used as a standard signal to lock the frequency of the to-be-locked laser 30. Although the laser of the to-be-locked laser 10 is used as a standard signal in this embodiment, the laser of the to-be-locked laser 20 in Figure 4 may also be used as a standard signal to lock the frequency of the to-be-locked laser 30.

[0051] In addition, the to-be-locked laser 10 in this embodiment can be stabilized together by the saturated absorption spectrum frequency stabilization assembly 100 and the super-stable cavity frequency stabilization assembly 200, or can be stabilized only by the saturated absorption spectrum frequency stabilization assembly 100.

[0052] Correspondingly, Figure 7 is a method for stabilizing the frequency of the to-be-locked laser 10 based on Figure 6 the laser frequency stabilization device shown in the embodiment. The method comprises the following steps:

[0053] Step S110c, frequency locking is performed on the to-be-locked laser 10, so that the laser emitted by the to-be-locked laser 10 is frequency-stable laser. Specifically, the laser emitted by the to-be-locked laser 10 is first split into two beams, one of the two beams is sent to the beat frequency frequency stabilization component 300, and the other of the two beams is sent to the saturated absorption spectrum frequency stabilization component 100 to stabilize the frequency of the to-be-locked laser 10. Alternatively, the other beam can be split into two beams, and the saturated absorption spectrum frequency stabilization component 100 and the super-stable cavity frequency stabilization component 200 are used to jointly stabilize the frequency of the to-be-locked laser 10.

[0054] Step S120c, the laser emitted by the to-be-locked laser 30 is sent to the beat frequency frequency stabilization component 300, and a locking signal is obtained by processing the laser emitted by the to-be-locked laser 30 and the laser emitted by the to-be-locked laser 10 by the beat frequency frequency stabilization component 300; wherein the wavelength of the to-be-locked laser 30 is the same as the wavelength of the to-be-locked laser 10.

[0055] Step S130c, the locking signal is injected into the to-be-locked laser 30 to perform frequency locking on the to-be-locked laser 30.

[0056] Through the above processing process, when the wavelengths of two lasers are the same, one of the two lasers can be stabilized according to the above-mentioned various methods, and then the laser with the same wavelength can be used to generate beat frequency interference, and the stabilized laser is used as a standard signal source to stabilize the other laser. In this way, the equipment is simplified, and the purpose of simultaneously stabilizing multiple lasers with the same wavelength is achieved.

[0057] Through the saturated absorption spectrum frequency stabilization component 100, the super-stable cavity frequency stabilization component 200, and the beat frequency frequency stabilization component 300, various methods for simultaneously stabilizing multiple lasers can be derived, for example:

[0058] Method one

[0059] The process of stabilizing two to-be-locked lasers 10 and 30 with the same wavelength is as follows:

[0060] The laser emitted by the to-be-locked laser 10 is processed by the saturated absorption spectrum frequency stabilization component 100 to obtain a locking signal.

[0061] The locking signal obtained by processing the laser emitted by the to-be-locked laser 10 by the saturated absorption spectrum frequency stabilization component 100 is injected into the to-be-locked laser 10 to perform frequency locking on the to-be-locked laser 10.

[0062] The laser emitted by the to-be-locked laser 30 (another laser with the same wavelength as the to-be-locked laser 10) and the laser emitted by the to-be-locked laser 10 are sent to the beat frequency frequency stabilization component 300, and a locking signal is obtained by processing the two lasers by the beat frequency frequency stabilization component 300.

[0063] The locking signal obtained by the beat frequency stabilizing component 300 is injected into the to-be-locked laser 30 to stabilize the frequency of the to-be-locked laser 30.

[0064] Method two

[0065] The frequency stabilization process for the two to-be-locked lasers 10 and 30 with the same wavelength is as follows:

[0066] The laser emitted by the to-be-locked laser 10 is processed by the saturated absorption spectrum frequency stabilizing component 100 to obtain a locking signal.

[0067] The locking signal is divided into a locking signal and a correction signal.

[0068] The locking signal obtained by the saturated absorption spectrum frequency stabilizing component 100 is injected into the to-be-locked laser 10 to stabilize the frequency of the to-be-locked laser 10;

[0069] The correction signal is injected into the super-stable cavity in the super-stable cavity frequency stabilizing component 200 to correct the cavity length of the super-stable cavity.

[0070] The laser emitted by the to-be-locked laser 10 is processed by the super-stable cavity frequency stabilizing component 200 to obtain a locking signal.

[0071] The locking signal obtained by the super-stable cavity frequency stabilizing component 200 is injected into the to-be-locked laser 10 to stabilize the frequency of the to-be-locked laser 10 together with the locking signal.

[0072] The laser emitted by the to-be-locked laser 30 and the laser emitted by the to-be-locked laser 10 are sent to the beat frequency stabilizing component 300, and a locking signal is obtained by processing the lasers by the beat frequency stabilizing component 300.

[0073] The locking signal obtained by the beat frequency stabilizing component 300 is injected into the to-be-locked laser 30 to stabilize the frequency of the to-be-locked laser 30.

[0074] Method three

[0075] When there are three lasers with different wavelengths that need to be stabilized at the same time, in order not to cause confusion with the previous description, in this embodiment, one of the lasers is referred to as the to-be-locked laser 10, and the other two lasers are both referred to as the to-be-locked laser 20. The frequency stabilization process in this embodiment is as follows:

[0076] The laser emitted by the to-be-locked laser 10 is processed by the saturated absorption spectrum frequency stabilizing component 100 to obtain a locking signal.

[0077] The locking signal is divided into a locking signal and a correction signal.

[0078] The locking signal obtained by processing the saturated absorption spectrum frequency stabilization component 100 is injected into the laser to be locked 10 to lock the frequency of the laser to be locked 10.

[0079] The correction signal is injected into the super stable cavity 210 in the super stable cavity frequency stabilization component 200 to correct the super stable cavity 210.

[0080] The two lasers emitted by the two lasers to be locked 20 are processed by the super stable cavity frequency stabilization component 200 respectively to obtain two locking signals.

[0081] The two locking signals obtained by processing the super stable cavity frequency stabilization component 200 are injected into the corresponding laser to be locked 20 to lock the frequency of the laser to be locked 20.

[0082] The laser frequency stabilization method provided by the application can be applied in any application scenario where multiple lasers work simultaneously. For example, four kinds of lasers with different wavelengths are usually needed in the experiment of trapping ytterbium ions, which are 369nm laser, 935nm laser and 638nm laser, and 399nm laser. The 369nm laser is used for Doppler cooling, state initialization and state detection; the 935nm laser and the 638nm laser are used for maintaining ion cooling and stable trapping; and the 399nm laser is used for the preparation of ytterbium ions. In order to realize long-time cooling and trapping, accurate manipulation and detection of ytterbium ions, the frequency of the laser needs to be kept stable for a long time. However, the resonant cavity in the actual laser is easily affected by the external environment, and the change of the cavity length of the resonant cavity will cause the frequency of the laser to drift. When the laser frequency stabilization device and method provided by the application is applied, one laser is selected as the laser 10, and the atomic and molecular saturated absorption spectrum signal is used as the standard signal to realize long-term stabilization of the laser 10. At the same time, the locking signal for realizing long-term stable frequency locking of the laser 10 is used to correct the cavity length of the super stable cavity, so that the super stable cavity can provide the standard signal for a long time and stably, and then the advantages of the super stable cavity are used to stabilize the frequency of the other several lasers, and finally the purpose of simultaneously stabilizing the frequency of multiple lasers is realized. It is not necessary to configure a set of frequency stabilization device for each laser, which reduces the use of equipment, saves cost, and simplifies the overall equipment.

[0083] It should be noted that the first, second, third, fourth, etc. in the above description are used to distinguish features with the same name in the same or different embodiments, and are not a quantitative limitation. Moreover, the present application is not limited to the specific configurations and processes described above or shown in the drawings. The above description is only a specific embodiment of the present application, and those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the described system, device, module or unit can refer to the corresponding process in the method embodiment, and it is not necessary to repeat it. It should be understood that the protection scope of the present application is not limited thereto, and any person skilled in the art can think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered within the protection scope of the present application.

Claims

1. A laser frequency stabilisation apparatus, characterised in that, The frequency stabilization assembly comprises a saturated absorption spectrum frequency stabilization assembly, an ultrastable cavity frequency stabilization assembly, a third beam splitting assembly and a beat frequency frequency stabilization assembly. The saturated absorption spectrum frequency stabilization assembly is connected with the first to-be-locked laser, and processes the laser emitted by the first to-be-locked laser to obtain a first locking signal and a correction signal; the first locking signal is injected into the first to-be-locked laser to lock the frequency of the first to-be-locked laser; and the correction signal is injected into the ultrastable cavity in the ultrastable cavity frequency stabilization assembly to correct the cavity length of the ultrastable cavity. The ultrastable cavity frequency stabilization assembly is connected with the second to-be-locked laser, and processes the laser emitted by the second to-be-locked laser to obtain a second locking signal; and the second locking signal is injected into the second to-be-locked laser to lock the frequency of the second to-be-locked laser. The third beam splitting assembly is connected with the laser output end of the first to-be-locked laser or the second to-be-locked laser, and splits the laser emitted by the first to-be-locked laser or the second to-be-locked laser into a third laser and a fourth laser; the third laser is transmitted to the beat frequency frequency stabilization assembly, and the fourth laser is transmitted to the saturated absorption spectrum frequency stabilization assembly; the beat frequency frequency stabilization assembly is connected with the third to-be-locked laser and the third beam splitting assembly; the third laser emitted by the first to-be-locked laser or the second to-be-locked laser and the laser emitted by the third to-be-locked laser are processed by the beat frequency frequency stabilization assembly to obtain a third locking signal; and the third locking signal is injected into the third to-be-locked laser to lock the frequency of the third to-be-locked laser; wherein the wavelength of the third to-be-locked laser is the same as the wavelength of the first to-be-locked laser or the second to-be-locked laser.

2. The apparatus of claim 1, wherein, The saturated absorption spectrum frequency stabilization assembly comprises a first beam splitting assembly, an atomic and molecular gas chamber, a first photodetector, a first reference signal source, a first phase-locked amplifier, a first PID controller and a power divider. The first beam splitting assembly is connected with the laser output end of the first to-be-locked laser, and splits the laser emitted by the first to-be-locked laser into pump light and probe light, and the pump light and the probe light are incident on the atomic and molecular gas chamber in opposite directions to generate a saturated absorption spectrum signal in the atomic and molecular gas chamber; the saturated absorption spectrum signal is converted into a first electric signal by the first photodetector; the first electric signal and a reference signal provided by the first reference signal source are processed by the first phase-locked amplifier to obtain an error signal; and the error signal is processed by the first PID controller and the power divider to obtain the first locking signal and the correction signal.

3. The apparatus of claim 1, wherein, The ultrastable cavity frequency stabilization assembly comprises an ultrastable cavity, a second photodetector, a second reference signal source, a second phase-locked amplifier and a second PID controller. The ultrastable cavity is connected with the second to-be-locked laser through an ultrastable cavity incident light path, and the laser emitted by the second to-be-locked laser is incident on the ultrastable cavity; reflected light reflected from the ultrastable cavity is converted into a second electric signal by the second photodetector; the second electric signal and a reference signal provided by the second reference signal source are processed by the second phase-locked amplifier to obtain an error signal; and the error signal is processed by the second PID controller to obtain the second locking signal.

4. The apparatus of claim 1, wherein, The second beam splitting assembly is connected with the laser output end of the first to-be-locked laser, and splits the laser emitted by the first to-be-locked laser into first laser and second laser, and the first laser is incident on the saturated absorption spectrum frequency stabilization assembly through an optical path. The second laser is incident on the super stable cavity frequency stabilization assembly through the super stable cavity incident optical path; the super stable cavity frequency stabilization assembly processes the second laser to obtain another first locking signal, and injects the another first locking signal into the first to-be-locked laser to lock the frequency of the first to-be-locked laser together with the first locking signal.

5. The apparatus of claim 2, wherein, The pump optical path comprises a modulator, and the pump light incident on the atomic and molecular cell is modulated pump light.

6. The apparatus of claim 3, wherein, The super stable cavity incident optical path comprises a modulator, and the light incident on the super stable cavity is modulated light.

7. The apparatus of claim 1, wherein, The power amplifier is arranged between the power divider and the super stable cavity, and is used for amplifying the correction signal injected into the super stable cavity.

8. The apparatus of claim 1, wherein The beat frequency frequency stabilization assembly comprises a beam combining assembly, a third photodetector, a third reference signal source, a third lock-in amplifier and a third PID controller. The third to-be-locked laser emits laser, and the laser and the third laser pass through the beam combining assembly to obtain a beat frequency interference signal; the beat frequency interference signal is converted into a third electric signal by the third photodetector, and the third electric signal and a reference signal provided by the third reference signal source pass through the third lock-in amplifier to obtain a beat frequency offset signal; the beat frequency offset signal is processed by the third PID controller to obtain a third locking signal; and the third locking signal is injected into the third to-be-locked laser to lock the frequency of the third to-be-locked laser.

9. A laser frequency stabilisation apparatus, characterised in that, The first beam splitting assembly is connected with the laser output end of the first to-be-locked laser, and splits the laser emitted by the first to-be-locked laser into first laser and second laser; the first laser is transmitted to the saturated absorption spectrum frequency stabilization assembly, and the second laser is transmitted to the beat frequency frequency stabilization assembly; the saturated absorption spectrum frequency stabilization assembly is connected with the first beam splitting assembly, and the first laser emitted by the first to-be-locked laser is processed by the saturated absorption spectrum frequency stabilization assembly to obtain a first locking signal; the first locking signal is injected into the first to-be-locked laser to lock the frequency of the first to-be-locked laser; the beat frequency frequency stabilization assembly is connected with the second to-be-locked laser and the first beam splitting assembly respectively, and the laser emitted by the second to-be-locked laser and the second laser emitted by the first to-be-locked laser are processed by the beat frequency frequency stabilization assembly to obtain a second locking signal; the second locking signal is injected into the second to-be-locked laser to lock the frequency of the second to-be-locked laser; and the wavelength of the second to-be-locked laser is the same as the wavelength of the first to-be-locked laser.

10. The apparatus of claim 9, wherein, The second beam splitting assembly is arranged between the first beam splitting assembly and the saturated absorption spectrum frequency stabilization assembly, splits the first laser into third laser and fourth laser, the third laser is incident on the saturated absorption spectrum frequency stabilization assembly through an optical path, and the fourth laser is incident on the super stable cavity frequency stabilization assembly through the super stable cavity incident optical path. The other first locking signal is obtained by the ultrastable cavity frequency stabilization assembly and is injected into the first to-be-locked laser to lock the frequency of the first to-be-locked laser together with the first locking signal.

11. The apparatus of claim 10, wherein, The ultrastable cavity frequency stabilization assembly is connected with the third to-be-locked laser through an optical path, processes the laser emitted by the third to-be-locked laser, and obtains a third locking signal; the third locking signal is injected into the third to-be-locked laser to lock the frequency of the third to-be-locked laser.

12. A method of laser frequency stabilization, comprising: The method comprises the following steps: The laser emitted by the first to-be-locked laser is processed by the saturated absorption spectrum frequency stabilization assembly to obtain a first locking signal and a correction signal; The first locking signal is injected into the first to-be-locked laser to lock the frequency of the first to-be-locked laser; The correction signal is injected into the ultrastable cavity to correct the cavity length of the ultrastable cavity; The laser emitted by the second to-be-locked laser is processed by the ultrastable cavity frequency stabilization assembly to obtain a second locking signal; The second locking signal is injected into the second to-be-locked laser to lock the frequency of the second to-be-locked laser; The laser emitted by the first locking laser or the second to-be-locked laser is split into third laser and fourth laser; The laser emitted by the third to-be-locked laser and the third laser are sent to the beat frequency frequency stabilization assembly, and the third locking signal is obtained by processing the beat frequency frequency stabilization assembly; wherein the wavelength of the third to-be-locked laser is the same as the wavelength of the first locking laser or the second to-be-locked laser; And The third locking signal is injected into the third to-be-locked laser to lock the frequency of the third to-be-locked laser.

13. The method of claim 12, wherein, Further comprising: The laser emitted by the first to-be-locked laser is split into first laser and second laser; The first laser is incident to the saturated absorption spectrum frequency stabilization assembly; The second laser is incident to the ultrastable cavity frequency stabilization assembly, and another first locking signal is obtained by the ultrastable cavity frequency stabilization assembly; And The other first locking signal is injected into the first to-be-locked laser to lock the frequency of the first to-be-locked laser together with the first locking signal.

14. A method of laser frequency stabilization, comprising: Further comprising: The laser emitted by the first to-be-locked laser is split into first laser and second laser; The first laser is processed by the saturated absorption spectrum frequency stabilization assembly to obtain a first locking signal; The first locking signal is injected into the first to-be-locked laser to lock the frequency of the first to-be-locked laser; The laser emitted by the second to-be-locked laser and the second laser are sent to the beat frequency frequency stabilization assembly, and a second locking signal is obtained by processing the beat frequency frequency stabilization assembly; wherein the wavelength of the second to-be-locked laser is the same as the wavelength of the first to-be-locked laser; And The second locking signal is injected into the second to-be-locked laser to lock the frequency of the second to-be-locked laser.

15. The method according to claim 14, characterized in that Further comprising: The first laser emitted by the first to-be-locked laser is split into third laser and fourth laser; The third laser is incident to the saturated absorption spectrum frequency stabilization assembly, and the first locking signal and the correction signal are obtained by processing the third laser by the saturated absorption spectrum frequency stabilization assembly and the power splitter; The first locking signal is injected into the first to-be-locked laser to lock the frequency of the first to-be-locked laser; The correction signal is injected into the ultrastable cavity in the ultrastable cavity frequency stabilization assembly to correct the cavity length of the ultrastable cavity; The fourth laser is incident to the ultrastable cavity frequency stabilization assembly, and another first locking signal is obtained by the ultrastable cavity frequency stabilization assembly; And The other first locking signal is injected into the first to-be-locked laser, and the first to-be-locked laser is frequency-locked together with the first locking signal.

16. The method of claim 15, wherein, Further comprising: The laser emitted by the second to-be-locked laser is processed by the super-stable cavity frequency stabilization assembly to obtain a second locking signal; And The second locking signal is injected into the second to-be-locked laser, and the second to-be-locked laser is frequency-locked.

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