A device for dynamically regulating a laser polarization state based on an acousto-optic device

Abstract

The application discloses a kind of based on acoustooptic device dynamic regulation and control laser polarization state device, belong to laser technical field, including laser beam splitting unit, for according to the polarization state and polarization angle of target laser to be generated, the incident laser is split and produces the two linear polarized laser of propagating direction and beam intensity adjustable;Acoustooptic phase control unit, for the linear polarized laser of second optical path is acoustooptically modulated to change its phase, while the frequency offset of linear polarized laser of second optical path is compensated, to control the phase difference between the linear polarized laser of second optical path and the linear polarized laser of first optical path;Beam direction adjustment assembly, control two linear polarized laser simultaneously incident into the polarization beam combining unit to obtain target laser.The application simple structure, low in cost, can generate various pulse string with specific polarization mode, thereby solve the technical problems that laser polarization state control device constitutes complex, cost is high, control flexibility is poor, regulation and control frequency is low.

Description

Technical Field

[0001] The present invention belongs to the field of laser technology, and more specifically, relates to a device for dynamically controlling laser polarization state based on an acousto-optic device. Background Art

[0002] In the fields of communication technology, optical imaging, optical storage, biomedicine, laser processing, etc., lasers with dynamically controllable polarization states and finely controlled polarization angles are required to act together on the target area. Taking laser processing as an example, laser polarization state control can improve the accuracy, quality and efficiency of processing. In the laser welding process, laser polarization state control can be used to adjust the polarization direction of the laser beam to optimize the molten pool shape and weld quality of the weld joint. By controlling the polarization state of the laser beam, precise control of the heat flux distribution and welding speed during the welding process can be achieved, thereby reducing welding deformation and cracking, and improving the strength and sealing of the weld joint. Under such requirements, the use of traditional polarization control elements has low controllability and poor flexibility in adjusting the polarization state. It is necessary to use a laser light source to form a laser with dynamically controlled polarization state through multiple phase control device devices.

[0003] Traditional polarization control devices and methods include polarization state control based on ordinary wave plates, polarization state control based on polarization beam splitters, polarization state control based on electro-optical crystal elements, etc. Polarization state control based on ordinary wave plates rotates linearly polarized laser light by a certain angle through a half-wave plate or converts linearly polarized light into elliptically polarized light or circularly polarized light through a quarter-wave plate. However, it can only be used for a specific wavelength and can only achieve one type of corresponding polarization conversion. It cannot be adjusted, which limits its application scenarios. Polarization state control based on polarization beam splitters uses the principle that polarization beam splitters have different reflectivities for polarized light in different directions. When a beam of polarized light is incident on a polarization beam splitter prism, it will be decomposed into two linearly polarized lights perpendicular to each other. The light parallel to the incident plane is transmitted, and the light perpendicular to the incident plane is reflected. However, the working effect of the polarization beam splitter prism is limited by the wavelength and can only be roughly measured. The components of row polarization selection limit their application scenarios; the polarization state control based on electro-optical crystal components mainly utilizes the phase adjustment effect of electro-optical crystals on lasers, and uses the electro-optical effect of electro-optical crystals to introduce different additional phases to the incident laser. This method can feedback adjust the additional phase introduced by the electro-optical crystal through the target polarization state. However, due to the high cost and large size of electro-optical crystals, a very high voltage is required to control the additional phase introduced by the electro-optical crystals. This method is highly sensitive to environmental conditions and external interference. At the same time, since higher voltages will bring high-voltage interference, it will affect the stability and performance of the system. The optical loss and aperture of electro-optical crystals are large, making it difficult to apply in scenarios with high integration.

[0004] In summary, traditional polarization state dynamic control devices have problems such as large size, low control frequency, difficulty in polarization state control, difficulty in polarization angle adjustment, high optical loss, and low damage threshold in high-integration and high-sensitivity scenarios. These problems limit the development space in the application of dynamic polarization state control, making it difficult to apply them in communication technology, laser processing, optical imaging, optical storage, biomedicine and other fields, and it is difficult to achieve polarization control of multiple or single pulses of pulsed laser. Summary of the Invention

[0005] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a device for dynamically controlling the laser polarization state based on an acousto-optic device, thereby solving the technical problems of the laser polarization state control device having a complex structure, high cost, poor control flexibility, and low control frequency.

[0006] To achieve the above objectives, according to one aspect of the present invention, a device for dynamically controlling the polarization state of laser light based on an acousto-optic device is provided, comprising: a laser beam splitting unit, an acousto-optic phase control unit, a polarization beam combining unit, and a beam direction adjustment component;

[0007] The laser beam splitting unit is arranged on the optical path of the incident laser, and is used to split the incident laser according to the polarization state and polarization angle of the target laser to be generated and generate two beams of linearly polarized laser light with adjustable propagation direction and beam intensity, and the two beams of linearly polarized laser light propagate along the first optical path and the second optical path respectively;

[0008] The acousto-optic phase control unit is arranged on the second optical path, and is used to acousto-optically modulate the linearly polarized laser light of the second optical path to change its phase, and at the same time compensate for the frequency offset of the linearly polarized laser light of the second optical path, thereby controlling the phase difference between the linearly polarized laser light of the second optical path and the linearly polarized laser light of the first optical path;

[0009] The beam direction adjustment component is arranged on the outgoing optical path of the laser beam splitting unit and / or the acousto-optic phase control unit, and is used to control the propagation directions of the two linearly polarized laser beams along the first optical path and the second optical path, so that the two linearly polarized laser beams with a phase difference are simultaneously incident on the polarization beam combining unit;

[0010] The polarization beam combining unit is used to combine two linearly polarized laser beams to obtain the target laser.

[0011] Preferably, the laser beam splitting unit includes a first acousto-optic modulator and a λ / 2 wave plate; the beam direction adjustment component includes a first plane mirror, a second plane mirror and a third plane mirror; the acousto-optic phase control unit includes a second acousto-optic modulator;

[0012] The first acousto-optic modulator is used to apply f0 to the incident laser. The acoustic field generates two polarized laser beams with different intensities but the same polarization, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam is deflected by 90° at a polarization angle by the λ / 2 wave plate, and then refracted along the first optical path by the first plane mirror and the third plane mirror, and then enters the polarization beam combining unit; the second polarized laser beam propagates along the second optical path and enters the second acousto-optic modulator;

[0013] The second acousto-optic modulator is used to apply f0 to the second polarized laser light of the second optical path. The modulated second polarized laser light is refracted by the second plane mirror and then enters the polarization beam combining unit.

[0014] Preferably, the laser beam splitting unit includes a polarization beam splitting prism and a λ / 2 wave plate, the beam direction adjustment component includes a first plane mirror, a second plane mirror and a third plane mirror; the acousto-optic phase control unit includes a first acousto-optic modulator and a second acousto-optic modulator;

[0015] The λ / 2 wave plate and the polarization beam splitter prism are sequentially arranged along the incident direction of the laser, and are used to control the beam splitting ratio of the incident laser to obtain a first polarized laser and a second polarized laser; the first polarized laser is reflected by the polarization beam splitter prism and propagates along the first optical path, and the third plane mirror is arranged on the first optical path, and is used to refract the first polarized laser and then enter the polarization beam combining unit; the second polarized laser is transmitted by the polarization beam splitter prism and propagates along the second optical path, and the first plane mirror, the first acousto-optic modulator, the second acousto-optic modulator, and the second plane mirror are sequentially arranged on the second optical path, and the first acousto-optic modulator and the second acousto-optic modulator are respectively used to apply f0 to the second polarized laser, The sound field and f0, The modulated second polarized laser light is refracted by the second plane mirror and then enters the polarization beam combining unit.

[0016] Preferably, the laser beam splitting unit includes a first acousto-optic modulator and a λ / 2 wave plate, the beam direction adjustment component includes a first plane mirror, a second plane mirror and a third plane mirror; the acousto-optic phase control unit includes a second acousto-optic modulator;

[0017] The first acousto-optic modulator is used to apply f0 to the incident laser. The acoustic field generates two polarized laser beams with different intensities but the same polarization, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam is refracted by the first plane mirror and the third plane mirror along the first optical path and then enters the polarization beam combining unit; the second polarized laser beam is deflected by 90° at the polarization angle of the λ / 2 wave plate and then propagates along the second optical path and enters the second acousto-optic modulator;

[0018] The second acousto-optic modulator is arranged perpendicular to the first acousto-optic modulator, and the second acousto-optic modulator is used to apply f0 to the second polarized laser light of the second optical path. The modulated second polarized laser light is refracted by the second plane mirror and then enters the polarization beam combining unit.

[0019] Preferably, the laser beam splitting unit includes a third acousto-optic modulator and a λ / 2 wave plate; the beam direction adjustment component includes a first plane mirror, a second plane mirror and a third plane mirror; the acousto-optic phase control unit includes a fourth acousto-optic modulator;

[0020] The third acousto-optic modulator is a +1-order anomalous Bragg diffraction acousto-optic modulator, and the polarization state of the diffracted light is deflected by 90° from p-light to s-light, and the fourth acousto-optic modulator is a -1-order anomalous Bragg diffraction acousto-optic modulator, and the polarization state of the diffracted light is deflected by 90° from s-light to p-light;

[0021] The third acousto-optic modulator is used to apply f0 to the incident laser. The acoustic field generates two polarized laser beams with different intensities and polarizations, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam is deflected by 90° at a polarization angle by the λ / 2 wave plate, and then refracted along the first optical path by the first plane mirror and the third plane mirror, and then enters the polarization beam combining unit; the second polarized laser beam propagates along the second optical path and enters the fourth acousto-optic modulator;

[0022] The fourth acousto-optic modulator is used to apply f0 to the second polarized laser light of the second optical path, The sound field is modulated and the polarization state of the diffracted light is deflected by 90 degrees. The second polarized laser light, which is converted from s light to p light, is refracted by the second plane mirror and then enters the polarization beam combining unit.

[0023] Preferably, the laser beam splitting unit includes a third acousto-optic modulator and a λ / 2 wave plate, the beam direction adjustment component includes a first plane mirror, a second plane mirror and a third plane mirror; the acousto-optic phase control unit includes a fourth acousto-optic modulator;

[0024] The third AOM is a +1-order anomalous Bragg diffraction AOM, and the polarization state of the diffracted light is deflected by 90° from p-light to s-light. The fourth AOM is a -1-order anomalous Bragg diffraction AOM, and the polarization state of the diffracted light is deflected by 90° from p-light to s-light. The fourth AOM is arranged perpendicular to the third AOM.

[0025] The third acousto-optic modulator is used to apply f0 to the incident laser. The acoustic field generates two polarized laser beams with different intensities and polarizations, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam is refracted by the first plane mirror and the third plane mirror along the first optical path and then enters the polarization beam combining unit; the second polarized laser beam is deflected by 90° at the polarization angle of the λ / 2 wave plate and then propagates along the second optical path and enters the fourth acousto-optic modulator;

[0026] The fourth optical modulator is used to apply f0 to the second polarized laser light of the second optical path, The sound field is modulated and the polarization state of the diffracted light is deflected by 90 degrees. The second polarized laser light, which is converted from p light to s light, is refracted by the second plane mirror and then enters the polarization beam combining unit.

[0027] Preferably, the laser beam splitting unit includes a first acousto-optic modulator; the beam direction adjustment component includes a first plane mirror, a second plane mirror and a third plane mirror; the acousto-optic phase control unit includes a fifth acousto-optic modulator;

[0028] The first acousto-optic modulator is used to apply f0 to the incident laser. The acoustic field generates two polarized laser beams with different intensities but the same polarization, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam is refracted by the first plane mirror and the third plane mirror along the first optical path and then enters the polarization beam combining unit; the second polarized laser beam propagates along the second optical path and enters the fifth acousto-optic modulator;

[0029] The fifth acousto-optic modulator is a -1 order anomalous Bragg diffraction acousto-optic modulator, and the polarization state of the diffracted light is deflected by 90° from p light to s light. The fifth acousto-optic modulator is used to apply f0 to the second polarized laser light of the second optical path. The second polarized laser light, which is modulated and has its polarization state deflected by 90° from p light to s light, is refracted by the second plane mirror and then enters the polarization beam combining unit.

[0030] Preferably, the laser beam splitting unit includes a third acousto-optic modulator; the beam direction adjustment component includes a first plane mirror, a second plane mirror and a third plane mirror; the acousto-optic phase control unit includes a second acousto-optic modulator;

[0031] The third acousto-optic modulator is a +1-order anomalous Bragg diffraction acousto-optic modulator, and the polarization state of the diffracted light is deflected by 90° from p-light to s-light. The third acousto-optic modulator is used to apply f0 to the incident laser. The acoustic field generates two polarized laser beams with different intensities and polarizations, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam is refracted along the first optical path by the first plane mirror and the third plane mirror respectively and then enters the polarization beam combining unit; the second polarized laser beam is transmitted along the second optical path and is incident on the second acousto-optic modulator;

[0032] The second acousto-optic modulator is used to apply f0 to the second polarized laser light of the second optical path. The modulated second polarized laser light is refracted by the second plane mirror and then enters the polarization beam combining unit.

[0033] Preferably, the polarization beam combining unit is a polarization beam splitting prism.

[0034] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0035] 1. The present invention proposes a device for dynamically controlling laser polarization states based on an acousto-optic device. The device comprises, in sequence, a laser beam splitting unit, an acousto-optic phase control unit, a polarization beam combining unit, and a beam direction adjustment component. These devices split, control, polarize, and combine the incident laser light, outputting laser light with a specific polarization pattern. This makes the entire system more flexible and controllable, while reducing costs. The laser beam splitting unit controls the splitting ratio of the incident laser light, that is, the intensity of the two polarized laser beams after splitting. The acousto-optic phase control unit controls the phase difference between the two polarized laser beams, and the beam direction adjustment component ensures that the total optical path length of the two optical paths is consistent. This achieves the goal of modulating only the polarization of the incident laser pulses to achieve a specific polarization pattern for subsequent amplification and combining when the incident laser light is a pulse train, facilitating the generation of laser light with different polarization states and angles through electrical control alone. This reduces the complexity and size of the polarization control system and allows for polarization control of even a single pulse, reducing the cost of the polarization-coherent beam combining system. Furthermore, the present invention utilizes an acousto-optic modulation device, which currently operates at speeds of hundreds of megahertz, matching the repetition rate of an ultrafast pulse oscillator and meeting the modulation rate requirements of ultrafast laser pulse trains.

[0036] 2. The present invention proposes a device for dynamically controlling the laser polarization state based on an acousto-optic device. The device controls the laser beam splitting unit to split the incident laser so that the two laser beams propagate in different directions. The operation is simple and flexible.

[0037] 3. The present invention proposes a device for dynamically controlling the polarization state of laser based on an acousto-optic device. The acousto-optic phase control unit applies an acoustic field of f0 to the linearly polarized laser in the second optical path to restore it to its original optical frequency without causing frequency shift. The phase difference between the two acoustic fields is used to adjust the polarization state of laser. Control the polarization state of the target laser with simple and flexible operation.

[0038] 4. The application provides a device for dynamically regulating laser polarization state based on an acousto-optic device, wherein a light beam direction adjusting assembly is arranged on the first light path and the second light path, so that the total optical path of the two light paths is consistent, facilitating polarization beam combining in the later stage. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 Fig. 1 is a structural schematic diagram of the device for dynamically regulating laser polarization state based on an acousto-optic device in an embodiment of the application;

[0040] Figure 2 Fig. 2 is a structural schematic diagram of the device for dynamically regulating laser polarization state based on an acousto-optic device in an embodiment of the application;

[0041] Figure 3 Fig. 3 is a structural schematic diagram of the device for dynamically regulating laser polarization state based on an acousto-optic device in an embodiment of the application;

[0042] Figure 4 Fig. 4 is a structural schematic diagram of the device for dynamically regulating laser polarization state based on an acousto-optic device in an embodiment of the application;

[0043] Figure 5 Fig. 5 is a structural schematic diagram of the device for dynamically regulating laser polarization state based on an acousto-optic device in an embodiment of the application;

[0044] Figure 6 Fig. 6 is a structural schematic diagram of the device for dynamically regulating laser polarization state based on an acousto-optic device in an embodiment of the application;

[0045] Figure 7 Fig. 7 is a structural schematic diagram of the device for dynamically regulating laser polarization state based on an acousto-optic device in an embodiment of the application;

[0046] Figure 8 Fig. 8 is a schematic diagram of the working principle of the acousto-optic modulator in the embodiment of the application;

[0047] Figure 9 Fig. 9 is a schematic diagram of the principle of the λ / 2 wave plate in the application;

[0048] In all the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-laser beam splitting unit; 2-acoustic-optic phase control unit; 3-polarization beam combining unit; 4-first acousto-optic modulator; 5-second acousto-optic modulator; 6-λ / 2 wave plate; 7-polarization beam splitting prism; 8-first plane mirror; 9-second plane mirror; 10-third plane mirror; 11-polarization beam splitting prism; 12-third acousto-optic modulator; 13-fourth acousto-optic modulator; 14-fifth acousto-optic modulator; 401-driving signal source; 402-electroacoustic transducer; 403-acousto-optic medium; 404-acoustic absorption device; 501-driving signal source; 502-electroacoustic transducer; 503-acousto-optic medium; 504-acoustic absorption device. DETAILED DESCRIPTION

[0049] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0050] like Figures 1-9 As shown, the present invention proposes a device for dynamically controlling the polarization state of laser based on an acousto-optic device, comprising a laser beam splitting unit 1, an acousto-optic phase control unit 2, a polarization beam combining unit 3 and a beam direction adjustment component; the laser beam splitting unit 1 is arranged on the optical path of the incident laser, and is used to split the incident laser according to the polarization state and polarization angle of the target laser to be generated and generate two beams of linearly polarized laser light with adjustable propagation direction and beam intensity, and the two beams of linearly polarized laser light propagate along a first optical path and a second optical path respectively; the acousto-optic phase control unit 2 is arranged on the second optical path, and is used to combine the linearly polarized laser light of the second optical path Acousto-optic modulation changes its phase and compensates for the frequency offset of the linearly polarized laser in the second optical path, thereby controlling the phase difference between the linearly polarized laser in the second optical path and the linearly polarized laser in the first optical path; the beam direction adjustment component is arranged on the output optical path of the laser beam splitting unit 1 and / or the acousto-optic phase control unit 2, and is used to control the propagation directions of the two linearly polarized laser beams along the first optical path and the second optical path, so that the two linearly polarized laser beams with phase difference are simultaneously incident on the polarization beam combining unit 3; the polarization beam combining unit 3 is used to combine the two linearly polarized laser beams to obtain the target laser.

[0051] The technical solution of the present invention is further illustrated below through specific embodiments.

[0052] Example 1

[0053] The embodiment provides a device for dynamically regulating a laser polarization state based on an acousto-optic device, which comprises a laser beam splitting unit 1, a beam direction adjusting assembly, an acousto-optic phase control unit 2 and a polarization beam combining unit 3; the laser beam splitting unit 1 is composed of a first acousto-optic modulator 4 and a lambda / 2 wave plate 6 and is arranged on the optical path of incident laser light, is used for acousto-optically modulating and controlling the diffraction efficiency of incident laser light according to the light polarization state and the polarization angle of target laser light to be generated, so that the incident laser light can be split into two beams of polarization light with controllable intensity, and the two beams of laser light with different polarizations are emitted along respective optical paths. The beam direction adjusting assembly is arranged on the emitted optical path of the laser beam splitting unit, the optical path comprises a first optical path and a second optical path, and the two optical paths correspond to equal optical paths; the acousto-optic phase control unit is composed of the first acousto-optic modulator 4 and is used for causing the p-polarized light in the second optical path to generate a phase shift of , so that the polarization pulse is obtained. The polarization beam combining unit is composed of a polarization beam splitter prism 7 and is used for combining the polarization pulses emitted from the respective optical paths, so that the laser light with the target polarization state is obtained.

[0054] Specifically, as shown in the figure, Figure 1 The device for dynamically regulating a laser polarization state based on an acousto-optic device comprises a laser beam splitting unit 1, a beam direction adjusting assembly, an acousto-optic phase control unit 2 and a polarization beam combining unit 3; the laser beam splitting unit 1 is composed of a first acousto-optic modulator 4 and a lambda / 2 wave plate 6; the beam direction adjusting assembly comprises a first plane mirror 8, a first plane mirror 9 and a first plane mirror 10; the acousto-optic phase control unit 2 is composed of a second acousto-optic modulator 5; and the polarization beam combining unit 3 is composed of a polarization beam splitter prism 7. The incident laser beam is incident towards the z-axis, the included angle between the incident direction and the z-axis is θB, and the incident polarization direction is the x-axis direction, that is, p-polarized laser light. The incident laser light is incident into the first acousto-optic modulator 4 at the Bragg angle θB, a sound wave with a frequency f0 and a phase is applied to the acousto-optic medium along the x direction, the diffracted light beam propagates along the second optical path after +1 order Bragg diffraction, the polarization direction of the diffracted light beam is the x-axis direction, that is, p-polarized laser light propagates along the second optical path, and it is noted that the frequency of the diffracted light wave is shifted at this time. After the transmitted light beam passes through the first acousto-optic modulator 4, the polarization direction is changed from the x-axis direction to the y-axis direction after passing through a lambda / 2 wave plate 6, that is, s-polarized laser light, and then propagates along the first optical path. Further, for the target laser light with different polarization modes required, only the amplitude of the modulation signal of the first acousto-optic modulator 4 needs to be changed, so that the splitting ratio of the two beams of emitted light meets the target polarization requirement, which is simple and convenient. In the second optical path, the p-polarized laser light emitted from the laser beam splitting unit is incident into the second acousto-optic modulator 5 at the Bragg angle, a sound wave with a frequency f0 and a phase The diffracted light beam continues to propagate along the second light path after undergoing -1 order Bragg diffraction, and further, for the target laser of different polarization modes, only the amplitude and phase of the modulation signal of the second acousto-optic modulator 5 need to be changed Note that at this time the diffracted light wave also undergoes frequency shift and becomes the original light frequency, and the phase difference between the p-polarized light beam of the second light path and the s-polarized laser of the first light path satisfies the target polarization requirement, which is simple and convenient.

[0055] The first acousto-optic modulator 4 and the first acousto-optic modulator 5 are normal Bragg diffraction acousto-optic modulators, which are used to selectively change the diffraction efficiency and light wave phase of the incident pulse, so that the incident light beam is modulated differently after passing through the acousto-optic modulator. By controlling the diffraction efficiency, transmitted light beams and diffracted light beams of different light intensities can be obtained, and by controlling the phase of the acoustic field, the light wave phase of the diffracted light beam can be controlled. The amplitude, frequency and phase of the modulation sound waves of the first acousto-optic modulator 4 and the second acousto-optic modulator 5 are adjustable. The amplitude of the modulation sound wave is used to change the diffraction efficiency of the incident pulse, that is, the beam splitting ratio. Further, the first acousto-optic modulator 4 and the second acousto-optic modulator 5 work based on the photoelastic effect of optical materials. Its performance is that when the sound wave propagates in some medium, the medium will produce elastic deformation corresponding to the sound wave signal, which changes periodically with time and space, thereby causing the periodic change of the refractive index of the medium, forming an equivalent phase grating, and the grating constant is equal to the sound wave wavelength. The light wave passing through this phase grating will diffract, and when the grating is thick enough, that is, the acousto-optic interaction length is large enough, it needs to be considered as a bulk grating, at this time only 0 order and +1 order (or -1 order) (depending on the direction of the incident light) diffraction occurs. The diffraction angle is related to the frequency of the sound wave, the diffraction efficiency is related to the amplitude of the sound wave, and the diffraction light phase is related to the phase of the sound wave. By changing the amplitude and phase of the modulation sound wave, the intensity and phase of the light wave can be changed.

[0056] The following is derived from the coupling wave equation to obtain elliptically polarized light. For this purpose, the medium through which the sound wave passes can be approximated as a number of mirrors that are partially reflective and partially transmissive, with a distance of the sound wave wavelength λ S between them. For a traveling wave ultrasonic field, these mirrors will move in the x direction with a speed υ S . Because the frequency of the sound wave is much lower than that of the light wave, at a certain instant, the ultrasonic field can be approximated as static, and thus has no effect on the intensity distribution of the diffracted light. For a standing wave ultrasonic field, it is completely static. The acousto-optic device is based on the Bragg diffraction effect. When the input single-frequency signal frequency is f0 and the power is P1, the incident laser will undergo Bragg diffraction, deviating by twice the Bragg angle θ = θ 2B , and the ratio of the intensity I out of the diffracted light beam to the intensity I in of the incident light beam is the diffraction efficiency η. According to the Bragg diffraction formula, we have

[0057]

[0058] where λ0 is the laser wavelength, L and H are the length and width of the ultrasonic transducer in the acousto-optic device, M2 is the acousto-optic quality determined by the crystal of the acousto-optic device, which can be obtained from a table, v S is the sound speed in the acousto-optic device crystal, and Δf is the sound field frequency change s The change in the polarization angle of the light beam caused by the change in the polarization angle of the light beam is

[0059]

[0060] When the laser beam splitting unit 1 needs to generate two light beams with different intensities, and the polarization states of the two generated light beams are the same, the first acousto-optic modulator 4 only needs an input frequency f0, and the driving source waveform signal is

[0061]

[0062] where is the phase corresponding to the input frequency f0, a1 represents the waveform intensity corresponding to the input frequency f0, The relationship between the power P1 and the power gain G of the radio frequency amplifier is related to the power gain G of the radio frequency amplifier, and in a 50-ohm radio frequency system, The corresponding relationship between the power P1 and the power gain G of the radio frequency amplifier is:

[0063]

[0064] Therefore, the beam diffraction efficiency distribution can be calculated from the target beam splitting intensity distribution, and the specific value of a1 can be calculated by combining the power gain of the radio frequency amplifier and the above formula.

[0065] Alternatively, The incident light beam passes through the first acousto-optic modulator to generate +1 order diffraction, and the diffracted light has a positive frequency shift of f0. The transmitted light beam passes through the λ / 2 wave plate 6, and the polarization direction changes from the x-axis direction to the y-axis direction, that is, the s-polarized laser, and then propagates along the first optical path. The light field expression of the two light beams can be obtained as:

[0066]

[0067] where Ω = 2πf0 is the angular frequency of the driving source waveform signal, and the incident light is split into two light beams according to the target requirements, wherein the s-polarized light in the first optical path is incident into the polarization beam combining unit 3 along the first optical path through the mirror, and the p-polarized light in the second optical path is incident into the acousto-optic phase control unit 2.

[0068] The phase of the acousto-optic driving source waveform signal s2(t) of the phase compensation unit is adjusted to control the phase of the second optical path light beam, and the driving source waveform signal s2(t) is:

[0069]

[0070] The s-polarized light in the first optical path is incident on the polarization beam splitter prism 7 in the polarization beam combining unit 3. At the same time, the p-polarized light in the second optical path that has passed through the acousto-optic phase control unit 2 is incident on the polarization beam splitter prism 7 in the polarization beam combining unit 3 from another direction. According to the light splitting characteristics of the polarization beam splitter prism, the s-polarized light is reflected and the p-polarized light is transmitted. Therefore, the two beams of light with mutually perpendicular polarization directions can be spatially combined into one beam of light. The p-polarized light in the second optical path generates -1 order diffraction after passing through the second acousto-optic modulator 5. The frequency offset of the p-polarized light that originally had a frequency offset of frequency f0 is compensated, and the frequency offset of the negative frequency offset of frequency f0 is eliminated. At the same time, the light field expression of the two beams is:

[0071]

[0072] Wherein, Φ1 is the additional phase introduced when the s-polarized light of the first optical path is emitted from the laser beam splitting unit to the polarization beam splitting prism 7 incident on the polarization beam combining unit 3 and propagates in free space, Φ2 is the additional phase introduced when the p-polarized light of the second optical path is emitted from the acousto-optic beam splitting unit to the polarization beam splitting prism 7 incident on the polarization beam combining unit 3 and propagates in free space, and the phase difference between the two beams is for

[0073]

[0074] To generate an elliptically polarized beam, the phase difference between the two beams is Should meet and The phase difference The relationship with the angle α of elliptically polarized light is:

[0075]

[0076] Therefore, the phase difference can be controlled To achieve the control of the polarization angle of elliptically polarized light. If the output is linearly polarized light, the phase difference between the two beams is Should meet and If the output is circularly polarized light, the phase difference between the two beams is Should meet and E s1 =E p2 .

[0077] The technical solution of the embodiment of the present invention controls the polarization state, intensity distribution and polarization angle of the laser by controlling the driving waveform of the laser beam splitting unit 1 and the driving waveform of the acousto-optic phase control unit 2. The optical path is easy to adjust and control, thereby realizing the function of dynamically controlling the polarization state of the light beam.

[0078] Example 2

[0079] In this embodiment, Figure 2 As shown, the present invention provides a device for dynamically controlling the polarization state of lasers based on an acousto-optic device, comprising: a laser beam splitting unit 1, a beam direction adjustment component, an acousto-optic phase control unit 2, and a polarization beam combining unit 3; the laser beam splitting unit 1 is composed of a λ / 2 wave plate 6 and a polarization beam splitting prism 11; the beam direction adjustment component includes: a first plane mirror 8, a first plane mirror 9, and a first plane mirror 10; the acousto-optic phase control unit 2 is composed of a first acousto-optic modulator 4 and a second acousto-optic modulator 5; and the polarization beam combining unit 3 is composed of a polarization beam splitting prism 7. Placed in the xyz coordinate system, the angle between the fast axis of the λ / 2 wave plate and the x-axis is denoted as θ i The system is defined using the Jones matrix, and the complex amplitude of the incident beam is expressed as E X In the x direction, it represents p-polarized light, E Y The y direction represents s-polarized light, and the complex amplitude of the beam after passing through the λ / 2 wave plate is expressed as

[0080]

[0081] The calculation is simplified to

[0082]

[0083] When the amplitude of the incident beam is expressed as or When the polarization direction of the incident light beam is parallel to the x-axis or parallel to the y-axis, it is assumed that the amplitude of the incident light beam is expressed as That is, the polarization direction is parallel to the x-axis, and the calculation can be simplified to

[0084]

[0085] At this time, when the angle θ between the fast axis of the λ / 2 wave plate and the x-axis is i When the complex amplitude of the beam after passing through the λ / 2 wave plate becomes The polarization direction of the incident light beam changes from being parallel to the x-axis to having an angle of 2θ with the x-axis. i , realizes the rotation of the polarization direction of the light beam, the angle θ i Different, then E X1 With E Y1The size of the polarization beam splitter is different. After passing through the polarization beam splitter prism 11, the x direction represents the p-polarized light being transmitted, and the y direction represents the s-polarized light being reflected, thus achieving laser output with different beam splitting ratios for the incident light beam. Among them, the s-polarized light propagates along the first optical path, and the p-polarized light propagates along the second optical path. Then the p-polarized light of the second optical path is incident on the acousto-optic phase control unit 2, and the specific results are the same as those of the conventional laser beam splitter prism 11. Figure 1 Approximate, no further details here.

[0086] Example 3

[0087] In this embodiment, Figure 3 As shown, the present invention provides a device for dynamically controlling the polarization state of lasers based on an acousto-optic device, comprising: a laser beam splitting unit 1, a beam direction adjustment component, an acousto-optic phase control unit 2, and a polarization beam combining unit 3; the laser beam splitting unit 1 is composed of a first acousto-optic modulator 4 and a λ / 2 wave plate 6; the beam direction adjustment component comprises: a first plane mirror 8, a first plane mirror 9, and a first plane mirror 10; the acousto-optic phase control unit 2 is composed of a second acousto-optic modulator 5; and the polarization beam combining unit 3 is composed of a polarization beam splitting prism 7. When the laser beam splitting unit 1 needs to generate two beams with different beam intensities and the polarization states of the two generated beams are the same, the first acousto-optic modulator 4 only needs one input frequency f0, and the phase The driving source waveform signal is used. After the incident light beam passes through the first acousto-optic modulator, it produces +1-order diffraction. The diffracted light has a positive frequency shift of frequency f0. The diffracted light beam passes through the λ / 2 wave plate 6, and its polarization direction changes from the x-axis direction to the y-axis direction. The y-axis direction is s-polarized laser light, and then propagates along the second optical path. The optical field expression of the two beams can be obtained as follows:

[0088]

[0089] Among them, Ω=2πf0 is the angular frequency of the driving source waveform signal. The incident light is split into two beams according to the target requirements. The p-polarized light in the first optical path is incident on the polarization beam combining unit 3 through the reflector along the first optical path, and the s-polarized light in the second optical path is incident on the acousto-optic phase control unit 2.

[0090] By adjusting the input frequency f0 of the acousto-optic driving source waveform signal s2(t) of the phase compensation unit, the phase The second acousto-optic modulator should be placed vertically with the first acousto-optic modulator to control the phase of the second light path beam and to ensure the diffraction efficiency. The p-polarized light in the first light path is incident on the polarization beam splitter prism 7 in the polarization beam combining unit 3, and the s-polarized light in the second light path passing through the second acousto-optic phase control unit 2 is incident on the polarization beam splitter prism 7 in the polarization beam combining unit 3 from another direction. According to the light splitting characteristics of the polarization beam splitter prism, the s-polarized light is reflected and the p-polarized light is transmitted, so that the two beams of light with perpendicular polarization directions can be combined into one beam of light in space. The p-polarized light in the second light path is diffracted by the second acousto-optic modulator 5 to generate the -1 order, and the frequency shift of the p-polarized light with the frequency f0 is compensated, so that the p-polarized light with the frequency f0 has a negative frequency shift and the frequency shift is eliminated. At the same time, the light field expressions of the two beams of light are:

[0091]

[0092] wherein Φ1 is the additional phase introduced by the p-polarized light in the first light path propagating in free space from the laser beam splitting unit to the polarization beam splitter prism 7 in the polarization beam combining unit 3, Φ2 is the additional phase introduced by the s-polarized light in the second light path propagating in free space from the acousto-optic beam splitting unit to the polarization beam splitter prism 7 in the polarization beam combining unit 3, and the phase difference between the two beams of light is

[0093]

[0094] To generate an elliptically polarized light beam, the phase difference between the two beams of light should satisfy and wherein the phase difference and the angle α of the elliptically polarized light satisfy the following relationship:

[0095]

[0096] Therefore, the polarization angle of the elliptically polarized light can be controlled by controlling the phase difference The specific results are approximately Figure 1 and will not be described here.

[0097] Embodiment 4

[0098] In this embodiment, as Figure 4 ​​As shown, the application provides a device for dynamically regulating laser polarization state based on acousto-optic device, which comprises: a laser beam splitting unit 1, a beam direction adjusting assembly, an acousto-optic phase control unit 2 and a polarization beam combining unit 3; the laser beam splitting unit 1 is composed of a third acousto-optic modulator 12 and a λ / 2 wave plate 6; the beam direction adjusting assembly comprises: a first plane mirror 8, a first plane mirror 9 and a first plane mirror 10; the acousto-optic phase control unit 2 is composed of a fourth acousto-optic modulator 13; and the polarization beam combining unit 3 is composed of a polarization beam splitter prism 7. The third acousto-optic modulator 12 is a +1 order abnormal Bragg diffraction acousto-optic modulator, which can realize conversion of p-polarization of an incident light beam into s-polarization of a diffracted light beam, and the transmitted light beam is p-polarization unchanged; the fourth acousto-optic modulator 13 is a -1 order abnormal Bragg diffraction acousto-optic modulator, which can realize conversion of s-polarization of an incident light beam into p-polarization of a diffracted light beam, and the transmitted light beam is s-polarization unchanged. The abnormal Bragg acousto-optic modulator is used for selectively changing the diffraction efficiency and the optical wave phase of the incident pulse, so that the incident light beam is modulated differently after passing through the acousto-optic modulator, the transmitted light beam and the diffracted light beam with different light intensities can be obtained by controlling the diffraction efficiency, and the optical wave phase of the diffracted light beam can be controlled by controlling the phase of the acoustic field. The amplitude, frequency and phase of the modulation acoustic wave of the third acousto-optic modulator 4 and the fourth acousto-optic modulator 5 are adjustable,

[0099] When the laser beam splitting unit 1 needs to generate two light beams with different intensities and different polarization states, the third acousto-optic modulator 12 only needs an input frequency f0 of a driving source waveform signal, and the phase of the driving source waveform signal, the incident light beam generates +1 order diffraction after passing through the third acousto-optic modulator, the diffracted light has a positive frequency offset of frequency f0, the transmitted light beam passes through the λ / 2 wave plate 6, the polarization direction changes from the x-axis direction to the y-axis direction, that is, s-polarization laser, and then propagates along the first light path. The light field expression of the two light beams can be obtained as:

[0100]

[0101] Wherein, Ω = 2πf0 is the angular frequency of the driving source waveform signal, and the incident light is split into two light beams according to the target requirement, wherein the s-polarization light in the first light path is incident into the polarization beam combining unit 3 along the first light path through the reflector, and the s-polarization light in the second light path is incident into the acousto-optic phase control unit 2.

[0102] By adjusting the input frequency f0 of the acousto-optic driving source waveform signal s2(t) of the phase compensation unit, the phase to control the phase of the second optical path light beam. The s-polarized light in the first optical path is incident on the polarization beam splitting prism 7 in the polarization beam combining unit 3, while the p-polarized light in the second optical path passing through the acousto-optic phase control unit 2 is incident on the polarization beam splitting prism 7 in the polarization beam combining unit 3 from the other direction. According to the light splitting characteristics of the polarization beam splitting prism, the s-polarized light is reflected and the p-polarized light is transmitted, so that the two beams of light with perpendicular polarization directions can be combined into one beam of light in space. The s-polarized light in the second optical path is diffracted by the fourth acousto-optic modulator 5 to generate the -1 order, and the frequency shift of the s-polarized light with the original frequency f0 is compensated, so that the s-polarized light with the negative frequency shift of the frequency f0 is obtained, and the frequency shift is eliminated. At the same time, the light field expressions of the two beams of light are:

[0103]

[0104] where Φ1 is the additional phase introduced by the s-polarized light in the first optical path when propagating in free space from the laser beam splitting unit to the polarization beam splitting prism 7 in the polarization beam combining unit 3, Φ2 is the additional phase introduced by the p-polarized light in the second optical path when propagating in free space from the acousto-optic beam splitting unit to the polarization beam splitting prism 7 in the polarization beam combining unit 3, and the phase difference between the two beams of light is

[0105]

[0106] To generate an elliptically polarized light beam, the phase difference between the two beams of light should satisfy and where the phase difference and the angle α of the elliptically polarized light satisfy the following relationship:

[0107]

[0108] Therefore, the control of the polarization angle of the elliptically polarized light can be realized by controlling the phase difference The specific results are approximately Figure 1 and will not be described here.

[0109] Example 5

[0110] In this embodiment, as Figure 5 ​​As shown, the present invention provides a device for dynamically controlling the polarization state of lasers based on an acousto-optic device, comprising: a laser beam splitting unit 1, a beam direction adjustment component, an acousto-optic phase control unit 2, and a polarization beam combining unit 3; the laser beam splitting unit 1 is composed of a third acousto-optic modulator 12 and a λ / 2 wave plate 6; the beam direction adjustment component comprises: a first plane mirror 8, a first plane mirror 9, and a first plane mirror 10; the acousto-optic phase control unit 2 is composed of a fourth acousto-optic modulator 13; and the polarization beam combining unit 3 is composed of a polarization beam splitting prism 7. When the laser beam splitting unit 1 needs to generate two beams with different intensities and the polarization states of the two generated beams are different, the third acousto-optic modulator 12 only needs one input frequency f0, and the phase The driving source waveform signal is used. After the incident light beam passes through the third acousto-optic modulator, it produces +1-order diffraction. The diffracted light has a positive frequency shift of frequency f0. The diffracted light beam is s-polarized light. After passing through the λ / 2 wave plate 6, the polarization direction changes from the y-axis direction to the x-axis direction. The x-axis direction is p-polarized laser light, and then propagates along the second optical path. The optical field expression of the two beams can be obtained as follows:

[0111]

[0112] Among them, Ω=2πf0 is the angular frequency of the driving source waveform signal. The incident light is split into two beams according to the target requirements. The p-polarized light in the first optical path is incident on the polarization beam combining unit 3 through the reflector along the first optical path, and the p-polarized light in the second optical path is incident on the acousto-optic phase control unit 2.

[0113] By adjusting the input frequency f0 of the acousto-optic driving source waveform signal s2(t) of the phase compensation unit, the phase To control the phase of the light beam in the second optical path, and in order to ensure the diffraction efficiency, the fourth acousto-optic modulator should be placed perpendicular to the third acousto-optic modulator. The p-polarized light in the first optical path is incident on the polarization beam splitter prism 7 in the polarization beam combining unit 3. At the same time, the s-polarized light in the second optical path that has passed through the acousto-optic phase control unit 2 is incident on the polarization beam splitter prism 7 in the polarization beam combining unit 3 from another direction. According to the light splitting characteristics of the polarization beam splitter prism, the s-polarized light is reflected and the p-polarized light is transmitted. Therefore, the two beams of light with mutually perpendicular polarization directions can be spatially combined into one beam of light. The p-polarized light in the second optical path generates -1 order diffraction after passing through the fourth acousto-optic modulator 13. The frequency offset of the p-polarized light that originally had a frequency offset of frequency f0 is compensated, and the negative frequency offset of the frequency f0 is eliminated. At the same time, the light field expression of the two beams is:

[0114]

[0115] Wherein, Φ1 is the additional phase introduced when the p-polarized light of the first optical path is emitted from the laser beam splitting unit to the polarization beam splitting prism 7 incident on the polarization beam combining unit 3 and propagates in free space, Φ2 is the additional phase introduced when the s-polarized light of the second optical path is emitted from the acousto-optic beam splitting unit to the polarization beam splitting prism 7 incident on the polarization beam combining unit 3 and propagates in free space, and the phase difference between the two beams is for

[0116]

[0117] To generate an elliptically polarized beam, the phase difference between the two beams is Should meet and The phase difference The relationship with the angle α of elliptically polarized light is:

[0118]

[0119] Therefore, the phase difference can be controlled The polarization angle of elliptically polarized light can be controlled. Figure 1 Approximate, no further details here.

[0120] Example 6

[0121] In this embodiment, Figure 6 As shown, the present invention provides a device for dynamically controlling the polarization state of lasers based on an acousto-optic device, comprising: a laser beam splitting unit 1, a beam direction adjustment component, an acousto-optic phase control unit 2 and a polarization beam combining unit 3; the laser beam splitting unit 1 is composed of a first acousto-optic modulator 4; the beam direction adjustment component comprises: a first plane mirror 8, a first plane mirror 9 and a first plane mirror 10; the acousto-optic phase control unit 2 is composed of a fifth acousto-optic modulator 14; the polarization beam combining unit 3 is composed of a polarization splitting prism 7. The fifth acousto-optic modulator 14 is a -1 order anomalous Bragg diffraction acousto-optic modulator, which can realize the conversion of the p-polarization of the incident beam into the s-polarization of the diffracted beam, and the p-polarization of the transmitted beam remains unchanged. When the laser beam splitting unit 1 needs to generate two beams with different beam intensities, and the polarization states of the two generated beams are the same, the first acousto-optic modulator 4 only needs one input frequency f0, and the phase The driving source waveform signal is , and the incident light beam produces +1-order diffraction after passing through the first acousto-optic modulator. The diffracted light has a positive frequency shift of frequency f0. The transmitted and diffracted light beams are both p-polarized light and propagate along their respective optical paths. The light field expressions of the two beams can be obtained as:

[0122]

[0123] Among them, Ω=2πf0 is the angular frequency of the driving source waveform signal. The incident light is split into two beams according to the target requirements. The p-polarized light in the first optical path is incident on the polarization beam combining unit 3 through the reflector along the first optical path, and the p-polarized light in the second optical path is incident on the acousto-optic phase control unit 2.

[0124] By adjusting the input frequency f0 of the acousto-optic driving source waveform signal s2(t) of the phase compensation unit, the phase To control the phase of the light beam in the second light path, and the fourth acousto-optic modulator will change the light beam in the second light path from p-polarized light to s-polarized light, then there is no need for a λ / 2 wave plate to perform polarization state conversion. The p-polarized light in the first light path is incident on the polarization beam splitter prism 7 in the polarization beam combining unit 3, and at the same time, the s-polarized light in the second light path that has passed through the acousto-optic phase control unit 2 is incident on the polarization beam splitter prism 7 in the polarization beam combining unit 3 from another direction. According to the light splitting characteristics of the polarization beam splitter prism, the s-polarized light is reflected and the p-polarized light is transmitted, so the two beams of light with mutually perpendicular polarization directions can be spatially synthesized into one beam of light. The p-polarized light in the second light path generates -1 order diffraction after passing through the fourth acousto-optic modulator 13, and the frequency offset of the p-polarized light that originally had a frequency offset of frequency f0 is compensated, and the frequency offset with a negative frequency offset of frequency f0 is eliminated. At the same time, the light field expression of the two beams is:

[0125]

[0126] Wherein, Φ1 is the additional phase introduced when the p-polarized light of the first optical path is emitted from the laser beam splitting unit to the polarization beam splitting prism 7 incident on the polarization beam combining unit 3 and propagates in free space, Φ2 is the additional phase introduced when the s-polarized light of the second optical path is emitted from the acousto-optic beam splitting unit to the polarization beam splitting prism 7 incident on the polarization beam combining unit 3 and propagates in free space, and the phase difference between the two beams is for

[0127]

[0128] To generate an elliptically polarized beam, the phase difference between the two beams is Should meet and The phase difference The relationship with the angle α of elliptically polarized light is:

[0129]

[0130] Therefore, the phase difference can be controlled The polarization angle of elliptically polarized light can be controlled. Figure 1 Approximate, no further details here.

[0131] Example 7

[0132] In this embodiment, Figure 7 As shown, the present invention provides a device for dynamically controlling the polarization state of lasers based on an acousto-optic device, comprising: a laser beam splitting unit 1, a beam direction adjustment component, an acousto-optic phase control unit 2, and a polarization beam combining unit 3; the laser beam splitting unit 1 is composed of a third acousto-optic modulator 12; the beam direction adjustment component comprises: a first plane mirror 8, a first plane mirror 9, and a first plane mirror 10; the acousto-optic phase control unit 2 is composed of a second acousto-optic modulator 5; and the polarization beam combining unit 3 is composed of a polarization beam splitting prism 7. When the laser beam splitting unit 1 needs to generate two beams with different intensities and the polarization states of the two generated beams are different, the third acousto-optic modulator 12 only needs one input frequency f0, and the phase The incident light beam generates a +1st-order diffraction after passing through the third acousto-optic modulator. The diffracted light has a positive frequency shift of f0, and its transmitted light beam is p-polarized light that propagates along the first optical path. The diffracted light beam is s-polarized light that propagates along the second optical path. The optical field expressions of the two beams can be obtained as follows:

[0133]

[0134] Among them, Ω=2πf0 is the angular frequency of the driving source waveform signal. The incident light is split into two beams according to the target requirements. The p-polarized light in the first optical path is incident on the polarization beam combining unit 3 through the reflector along the first optical path, and the s-polarized light in the second optical path is incident on the acousto-optic phase control unit 2.

[0135] By adjusting the input frequency f0 of the acousto-optic driving source waveform signal s2(t) of the phase compensation unit, the phase To control the phase of the light beam in the second optical path. The p-polarized light in the first optical path is incident on the polarization beam splitter prism 7 in the polarization beam combining unit 3. At the same time, the s-polarized light in the second optical path that has passed through the acousto-optic phase control unit 2 is incident on the polarization beam splitter prism 7 in the polarization beam combining unit 3 from another direction. According to the light splitting characteristics of the polarization beam splitter prism, the s-polarized light is reflected and the p-polarized light is transmitted. Therefore, the two beams of light with mutually perpendicular polarization directions can be spatially combined into one beam of light. The p-polarized light in the second optical path generates -1 order diffraction after passing through the second acousto-optic modulator 13. The frequency offset of the s-polarized light that originally had a frequency offset of frequency f0 is compensated, and the negative frequency offset of the frequency f0 is eliminated. At the same time, the light field expression of the two beams is:

[0136]

[0137] Wherein, Φ1 is the additional phase introduced when the p-polarized light of the first optical path is emitted from the laser beam splitting unit to the polarization beam splitting prism 7 incident on the polarization beam combining unit 3 and propagates in free space, Φ2 is the additional phase introduced when the s-polarized light of the second optical path is emitted from the acousto-optic beam splitting unit to the polarization beam splitting prism 7 incident on the polarization beam combining unit 3 and propagates in free space, and the phase difference between the two beams is for

[0138]

[0139] To generate an elliptically polarized beam, the phase difference between the two beams is Should meet and The phase difference The relationship with the angle α of elliptically polarized light is:

[0140]

[0141] Therefore, the phase difference can be controlled The polarization angle of elliptically polarized light can be controlled. Figure 1 Approximate, no further details here.

[0142] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for dynamically controlling laser polarization state based on an acousto-optic device, characterized in that: include: Laser beam splitting unit (1), acousto-optic phase control unit (2), polarization beam combining unit (3) and beam direction adjustment component; The laser beam splitting unit (1) is arranged on the optical path of the incident laser and is used to split the incident laser according to the polarization state and polarization angle of the target laser to be generated and generate two beams of linearly polarized laser light with adjustable propagation direction and beam intensity, and the two beams of linearly polarized laser light propagate along the first optical path and the second optical path respectively; The acousto-optic phase control unit (2) is arranged on the second optical path, and is used to acousto-optically modulate the linearly polarized laser light of the second optical path to change its phase, and at the same time compensate for the frequency offset of the linearly polarized laser light of the second optical path, thereby controlling the phase difference between the linearly polarized laser light of the second optical path and the linearly polarized laser light of the first optical path; The beam direction adjustment component is arranged on the output light path of the laser beam splitting unit (1) and / or the acousto-optic phase control unit (2), and is used to control the propagation directions of the two linearly polarized laser beams along the first light path and the second light path, so that the two linearly polarized laser beams with a phase difference are simultaneously incident on the polarization beam combining unit (3); The polarization beam combining unit (3) is used to combine two beams of linearly polarized laser light to obtain the target laser light; The laser beam splitting unit (1) comprises a first acousto-optic modulator (4) and wave plate (6); the light beam direction adjustment component includes a first plane mirror (8), a second plane mirror (9) and a third plane mirror (10); the acousto-optic phase control unit (2) includes a second acousto-optic modulator (5); The first acousto-optic modulator (4) is used to apply an acoustic field of f0, φ1 to the incident laser to generate two polarized laser beams with different intensities but the same polarization, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam passes through the After the polarization angle of the wave plate (6) is deflected by 90°, it is refracted along the first optical path by the first plane mirror (8) and the third plane mirror (10) and then incident on the polarization beam combining unit (3); the second polarized laser light propagates along the second optical path and is incident on the second acousto-optic modulator (5); The second acousto-optic modulator (5) is used to apply an acoustic field of f0, φ2 to the second polarized laser light of the second optical path, and the modulated second polarized laser light is refracted by the second plane mirror (9) and then incident on the polarization beam combining unit (3).

2. A device for dynamically controlling laser polarization state based on an acousto-optic device, characterized in that: include: Laser beam splitting unit (1), acousto-optic phase control unit (2), polarization beam combining unit (3) and beam direction adjustment component; The laser beam splitting unit (1) is arranged on the optical path of the incident laser and is used to split the incident laser according to the polarization state and polarization angle of the target laser to be generated and generate two beams of linearly polarized laser light with adjustable propagation direction and beam intensity, and the two beams of linearly polarized laser light propagate along the first optical path and the second optical path respectively; The acousto-optic phase control unit (2) is arranged on the second optical path, and is used to acousto-optically modulate the linearly polarized laser light of the second optical path to change its phase, and at the same time compensate for the frequency offset of the linearly polarized laser light of the second optical path, thereby controlling the phase difference between the linearly polarized laser light of the second optical path and the linearly polarized laser light of the first optical path; The beam direction adjustment component is arranged on the output light path of the laser beam splitting unit (1) and / or the acousto-optic phase control unit (2), and is used to control the propagation directions of the two linearly polarized laser beams along the first light path and the second light path, so that the two linearly polarized laser beams with a phase difference are simultaneously incident on the polarization beam combining unit (3); The polarization beam combining unit (3) is used to combine two beams of linearly polarized laser light to obtain the target laser light; The laser beam splitting unit (1) comprises a polarization beam splitting prism (11) and The wave plate (6) is provided, wherein the light beam direction adjustment component includes a first plane mirror (8), a second plane mirror (9) and a third plane mirror (10); the acousto-optic phase control unit (2) includes a first acousto-optic modulator (4) and a second acousto-optic modulator (5); described The wave plate (6) and the polarization beam splitter prism (11) are sequentially arranged along the incident direction of the laser, and are used to control the beam splitting ratio of the incident laser to obtain a first polarized laser and a second polarized laser; the first polarized laser is reflected by the polarization beam splitter prism (11) and propagates along a first optical path, and the third plane mirror (10) is arranged on the first optical path, and is used to refract the first polarized laser and then enter the polarization beam combining unit (3); the second polarized laser is transmitted through the polarization beam splitter prism (11) and propagates along a second optical path, and the first plane mirror (8), the first acousto-optic modulator (4), the second acousto-optic modulator (5) and the second plane mirror (9) are sequentially arranged on the second optical path, and the first acousto-optic modulator (4) and the second acousto-optic modulator (5) are used to apply an acoustic field of f0, φ1 and an acoustic field of f0, φ2 to the second polarized laser, respectively, and the modulated second polarized laser is refracted by the second plane mirror (9) and then enters the polarization beam combining unit (3).

3. A device for dynamically controlling laser polarization state based on an acousto-optic device, characterized in that: include: Laser beam splitting unit (1), acousto-optic phase control unit (2), polarization beam combining unit (3) and beam direction adjustment component; The laser beam splitting unit (1) is arranged on the optical path of the incident laser and is used to split the incident laser according to the polarization state and polarization angle of the target laser to be generated and generate two beams of linearly polarized laser light with adjustable propagation direction and beam intensity, and the two beams of linearly polarized laser light propagate along the first optical path and the second optical path respectively; The acousto-optic phase control unit (2) is arranged on the second optical path, and is used to acousto-optically modulate the linearly polarized laser light of the second optical path to change its phase, and at the same time compensate for the frequency offset of the linearly polarized laser light of the second optical path, thereby controlling the phase difference between the linearly polarized laser light of the second optical path and the linearly polarized laser light of the first optical path; The beam direction adjustment component is arranged on the output light path of the laser beam splitting unit (1) and / or the acousto-optic phase control unit (2), and is used to control the propagation directions of the two linearly polarized laser beams along the first light path and the second light path, so that the two linearly polarized laser beams with a phase difference are simultaneously incident on the polarization beam combining unit (3); The polarization beam combining unit (3) is used to combine two beams of linearly polarized laser light to obtain the target laser light; The laser beam splitting unit (1) comprises a first acousto-optic modulator (4) and The wave plate (6) is provided, wherein the light beam direction adjustment component comprises a first plane mirror (8), a second plane mirror (9) and a third plane mirror (10); the acousto-optic phase control unit (2) comprises a second acousto-optic modulator (5); The first acousto-optic modulator (4) is used to apply an acoustic field of f0, φ1 to the incident laser, thereby generating two polarized laser beams with different intensities but the same polarization, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam is refracted along the first optical path by the first plane mirror (8) and the third plane mirror (10) and then enters the polarization beam combining unit (3); the second polarized laser beam passes through the After the polarization angle of the wave plate (6) is deflected by 90°, it propagates along the second optical path and is incident on the second acousto-optic modulator (5); The second acousto-optic modulator (5) is arranged perpendicular to the first acousto-optic modulator (4), and the second acousto-optic modulator (5) is used to apply an acoustic field of f0, φ2 to the second polarized laser light of the second optical path, and the modulated second polarized laser light is refracted by the second plane mirror (9) and then incident on the polarization beam combining unit (3).

4. A device for dynamically controlling laser polarization state based on an acousto-optic device, characterized in that: include: Laser beam splitting unit (1), acousto-optic phase control unit (2), polarization beam combining unit (3) and beam direction adjustment component; The laser beam splitting unit (1) is arranged on the optical path of the incident laser and is used to split the incident laser according to the polarization state and polarization angle of the target laser to be generated and generate two beams of linearly polarized laser light with adjustable propagation direction and beam intensity, and the two beams of linearly polarized laser light propagate along the first optical path and the second optical path respectively; The acousto-optic phase control unit (2) is arranged on the second optical path, and is used to acousto-optically modulate the linearly polarized laser light of the second optical path to change its phase, and at the same time compensate for the frequency offset of the linearly polarized laser light of the second optical path, thereby controlling the phase difference between the linearly polarized laser light of the second optical path and the linearly polarized laser light of the first optical path; The beam direction adjustment component is arranged on the output light path of the laser beam splitting unit (1) and / or the acousto-optic phase control unit (2), and is used to control the propagation directions of the two linearly polarized laser beams along the first light path and the second light path, so that the two linearly polarized laser beams with a phase difference are simultaneously incident on the polarization beam combining unit (3); The polarization beam combining unit (3) is used to combine two beams of linearly polarized laser light to obtain the target laser light; The laser beam splitting unit (1) includes a third acousto-optic modulator (12) and wave plate (6); the beam direction adjustment component includes a first plane mirror (8), a second plane mirror (9) and a third plane mirror (10); the acousto-optic phase control unit (2) includes a fourth acousto-optic modulator (13); The third acousto-optic modulator (12) is a +1-order anomalous Bragg diffraction acousto-optic modulator, and the polarization state of the diffracted light is deflected by 90° from p-light to s-light, and the fourth acousto-optic modulator (13) is a -1-order anomalous Bragg diffraction acousto-optic modulator, and the polarization state of the diffracted light is deflected by 90° from s-light to p-light; The third acousto-optic modulator (12) is used to apply an acoustic field of f0, φ1 to the incident laser to generate two polarized laser beams with different intensities and polarizations, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam passes through the After the polarization angle of the wave plate (6) is deflected by 90°, it is refracted along the first optical path by the first plane mirror (8) and the third plane mirror (10) and then incident on the polarization beam combining unit (3); the second polarized laser light propagates along the second optical path and is incident on the fourth acousto-optic modulator (13); The fourth acousto-optic modulator (13) is used to apply an acoustic field of f0, φ2 to the second polarized laser light of the second optical path, and the polarization state of the modulated and diffracted light is deflected by 90°. The second polarized laser light is converted from s light to p light and is refracted by the second plane mirror (9) before entering the polarization beam combining unit (3).

5. A device for dynamically controlling laser polarization state based on an acousto-optic device, characterized in that: include: Laser beam splitting unit (1), acousto-optic phase control unit (2), polarization beam combining unit (3) and beam direction adjustment component; The laser beam splitting unit (1) is arranged on the optical path of the incident laser and is used to split the incident laser according to the polarization state and polarization angle of the target laser to be generated and generate two beams of linearly polarized laser light with adjustable propagation direction and beam intensity, and the two beams of linearly polarized laser light propagate along the first optical path and the second optical path respectively; The acousto-optic phase control unit (2) is arranged on the second optical path, and is used to acousto-optically modulate the linearly polarized laser light of the second optical path to change its phase, and at the same time compensate for the frequency offset of the linearly polarized laser light of the second optical path, thereby controlling the phase difference between the linearly polarized laser light of the second optical path and the linearly polarized laser light of the first optical path; The beam direction adjustment component is arranged on the output light path of the laser beam splitting unit (1) and / or the acousto-optic phase control unit (2), and is used to control the propagation directions of the two linearly polarized laser beams along the first light path and the second light path, so that the two linearly polarized laser beams with a phase difference are simultaneously incident on the polarization beam combining unit (3); The polarization beam combining unit (3) is used to combine two beams of linearly polarized laser light to obtain the target laser light; The laser beam splitting unit (1) includes a third acousto-optic modulator (12) and A wave plate (6), the light beam direction adjustment component includes a first plane mirror (8), a second plane mirror (9), and a third plane mirror (10); the acousto-optic phase control unit (2) includes a fourth acousto-optic modulator (13); The third acousto-optic modulator (12) is a +1-order anomalous Bragg diffraction acousto-optic modulator, and the polarization state of the diffracted light is deflected by 90° from p-light to s-light, and the fourth acousto-optic modulator (13) is a -1-order anomalous Bragg diffraction acousto-optic modulator, and the polarization state of the diffracted light is deflected by 90° from p-light to s-light; and the fourth acousto-optic modulator (13) is arranged perpendicular to the third acousto-optic modulator (12), The third acousto-optic modulator (12) is used to apply an acoustic field of f0, φ1 to the incident laser, thereby generating two polarized laser beams with different intensities and polarizations, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam is refracted along the first optical path by the first plane mirror (8) and the third plane mirror (10) and then enters the polarization beam combining unit (3); the second polarized laser beam passes through the After the polarization angle of the wave plate (6) is deflected by 90°, it propagates along the second optical path and is incident on the fourth acousto-optic modulator (13); The fourth acousto-optic modulator (13) is used to apply an acoustic field of f0, φ2 to the second polarized laser light of the second optical path, and the polarization state of the modulated and diffracted light is deflected by 90°. The second polarized laser light is converted from p-light to s-light and is refracted by the second plane mirror (9) before entering the polarization beam combining unit (3).

6. A device for dynamically controlling laser polarization state based on an acousto-optic device, characterized in that: include: Laser beam splitting unit (1), acousto-optic phase control unit (2), polarization beam combining unit (3) and beam direction adjustment component; The laser beam splitting unit (1) is arranged on the optical path of the incident laser and is used to split the incident laser according to the polarization state and polarization angle of the target laser to be generated and generate two beams of linearly polarized laser light with adjustable propagation direction and beam intensity, and the two beams of linearly polarized laser light propagate along the first optical path and the second optical path respectively; The acousto-optic phase control unit (2) is arranged on the second optical path, and is used to acousto-optically modulate the linearly polarized laser light of the second optical path to change its phase, and at the same time compensate for the frequency offset of the linearly polarized laser light of the second optical path, thereby controlling the phase difference between the linearly polarized laser light of the second optical path and the linearly polarized laser light of the first optical path; The beam direction adjustment component is arranged on the output light path of the laser beam splitting unit (1) and / or the acousto-optic phase control unit (2), and is used to control the propagation directions of the two linearly polarized laser beams along the first light path and the second light path, so that the two linearly polarized laser beams with a phase difference are simultaneously incident on the polarization beam combining unit (3); The polarization beam combining unit (3) is used to combine two beams of linearly polarized laser light to obtain the target laser light; The laser beam splitting unit (1) includes a first acousto-optic modulator (4); the beam direction adjustment component includes a first plane mirror (8), a second plane mirror (9) and a third plane mirror (10); the acousto-optic phase control unit (2) includes a fifth acousto-optic modulator (14); The first acousto-optic modulator (4) is used to apply an acoustic field of f0, φ1 to the incident laser, thereby generating two polarized laser beams with different intensities but the same polarization, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam is refracted along a first optical path by the first plane mirror (8) and the third plane mirror (10) and then incident on the polarization beam combining unit (3); the second polarized laser beam propagates along a second optical path and is incident on the fifth acousto-optic modulator (14); The fifth acousto-optic modulator (14) is a -1 order anomalous Bragg diffraction acousto-optic modulator and the polarization state of the diffracted light is deflected by 90° from p-light to s-light. The fifth acousto-optic modulator (14) is used to apply an acoustic field of f0, φ2 to the second polarized laser light of the second optical path. The second polarized laser light that is modulated and whose polarization state is deflected by 90° from p-light to s-light is refracted by the second plane mirror (9) and then enters the polarization beam combining unit (3).

7. A device for dynamically controlling laser polarization state based on an acousto-optic device, characterized in that: include: Laser beam splitting unit (1), acousto-optic phase control unit (2), polarization beam combining unit (3) and beam direction adjustment component; The laser beam splitting unit (1) is arranged on the optical path of the incident laser and is used to split the incident laser according to the polarization state and polarization angle of the target laser to be generated and generate two beams of linearly polarized laser light with adjustable propagation direction and beam intensity, and the two beams of linearly polarized laser light propagate along the first optical path and the second optical path respectively; The acousto-optic phase control unit (2) is arranged on the second optical path, and is used to acousto-optically modulate the linearly polarized laser light of the second optical path to change its phase, and at the same time compensate for the frequency offset of the linearly polarized laser light of the second optical path, thereby controlling the phase difference between the linearly polarized laser light of the second optical path and the linearly polarized laser light of the first optical path; The beam direction adjustment component is arranged on the output light path of the laser beam splitting unit (1) and / or the acousto-optic phase control unit (2), and is used to control the propagation directions of the two linearly polarized laser beams along the first light path and the second light path, so that the two linearly polarized laser beams with a phase difference are simultaneously incident on the polarization beam combining unit (3); The polarization beam combining unit (3) is used to combine two beams of linearly polarized laser light to obtain the target laser light; The laser beam splitting unit (1) includes a third acousto-optic modulator (12); the beam direction adjustment component includes a first plane mirror (8), a second plane mirror (9) and a third plane mirror (10); the acousto-optic phase control unit (2) includes a second acousto-optic modulator (5); The third acousto-optic modulator (12) is a +1-order anomalous Bragg diffraction acousto-optic modulator, and the polarization state of the diffracted light undergoes a 90° deflection from p-light to s-light. The third acousto-optic modulator (12) is used to apply an acoustic field of f0, φ1 to the incident laser, thereby generating two polarized laser beams with different intensities and polarizations, namely a first polarized laser beam and a second polarized laser beam; the first polarized laser beam is refracted along the first plane mirror (8) and the third plane mirror (10) along the first optical path and then incident on the polarization beam combining unit (3); the second polarized laser beam propagates along the second optical path and is incident on the second acousto-optic modulator (5); The second acousto-optic modulator (5) is used to apply an acoustic field of f0, φ2 to the second polarized laser light of the second optical path, and the modulated second polarized laser light is refracted by the second plane mirror (9) and then incident on the polarization beam combining unit (3).

8. The device for dynamically controlling laser polarization state based on an acousto-optic device according to any one of claims 1 to 7, characterized in that: The polarization beam combining unit (3) is a polarization beam splitting prism (7).

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