Laser polarization state control device and method for ultrafast laser processing

Abstract

The invention discloses a laser polarization state control device and method for ultrafast laser processing, and belongs to the field of laser processing, the laser polarization state control device comprises a laser, an electric 1 / 2 wave plate, a spatial light modulator, a reflector group, an electric 1 / 4 wave plate, a spectroscope, a polarization detection system and a control module, the electric 1 / 2 wave plate, the spatial light modulator and the electric 1 / 4 wave plate are all electrically connected with the control module, and the control module is used for controlling the electric 1 / 2 wave plate to rotate, controlling the spatial light modulator to perform phase modulation and controlling the electric 1 / 4 wave plate to rotate. Therefore, the adjustable range of the polarization state of the laser beam can be improved, and the laser polarization state control device can achieve modulation of radial polarization and angular polarization.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser processing, and in particular relates to a laser polarization state control device and method for ultrafast laser processing. Background Art

[0002] Ultrafast laser technology is a laser cold processing technology with a pulse width of picoseconds or femtoseconds. It is widely used in aerospace, medical, electronic packaging and other fields due to its low thermal impact, stress-free, and non-selective characteristics. Among them, in the ultrafast laser process, the polarization state of the laser beam used for processing has a great influence on the material removal efficiency and the microstructure of the material, so a laser polarization state control device is required to control the polarization state of the laser beam.

[0003] At present, the common laser polarization state control device includes a laser, a rotating half-wave plate and a driving mechanism. The laser emitted by the laser is emitted through the rotating half-wave plate. The driving mechanism controls the rotation of the rotating half-wave plate to achieve the conversion between horizontal polarized light and vertical polarized light, thereby achieving the modulation of the polarization state of the laser beam. However, when this structure is adopted, the adjustable range of the polarization state of the laser beam is limited, and the modulation of radial polarization and angular polarization cannot be achieved. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a laser polarization state control device and method for ultrafast laser processing. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] In a first aspect, the present invention provides a laser polarization state control device for ultrafast laser processing, comprising a laser, an electric 1 / 2 wave plate, a spatial light modulator, a reflector group, an electric 1 / 4 wave plate, a beam splitter, a polarization analyzer system and a control module, wherein the laser and the electric 1 / 2 wave plate are arranged opposite to each other, the electric 1 / 4 wave plate and the polarization analyzer system are arranged opposite to the beam splitter, and the electric 1 / 2 wave plate, the spatial light modulator and the electric 1 / 4 wave plate are electrically connected to the control module;

[0006] The laser light emitted by the laser enters the spatial light modulator through the electric 1 / 2 wave plate, propagates to the reflector group through the spatial light modulator, is reflected to the electric 1 / 4 wave plate through the reflector group, propagates to the beam splitter through the electric 1 / 4 wave plate, and is reflected to the polarization analyzer system through the beam splitter, wherein the laser light transmitted through the beam splitter is used for laser processing, and the control module is used to control the electric 1 / 2 wave plate to rotate, control the spatial light modulator to perform phase modulation, and control the electric 1 / 4 wave plate to rotate, so as to adjust the polarization state of the laser light emitted through the electric 1 / 4 wave plate.

[0007] In one embodiment of the present invention, the polarization analyzer system includes an electric polarization analyzer, a focusing mirror and a beam analyzer arranged in sequence. The laser is reflected to the electric polarization analyzer through a beam splitter, emitted to the focusing mirror through the electric polarization analyzer, and converged to the beam analyzer through the focusing mirror.

[0008] In one embodiment of the present invention, a beam expander is also included. The beam expander is arranged between the laser and the electric 1 / 2 wave plate. The laser light emitted by the laser enters the electric 1 / 2 wave plate after being expanded by the beam expander.

[0009] In one embodiment of the present invention, the reflector group includes a first lens, a first reflector, a second reflector, a second lens, a third reflector and a fourth reflector, the first lens and the second lens form a 4f system, and the lasers passing through the electric 1 / 2 wave plate and the electric 1 / 4 wave plate are all propagated in the horizontal direction;

[0010] The laser is emitted to the first lens through the spatial light modulator, transmitted to the first reflector through the first lens, reflected to the second lens through the first reflector and the second reflector, transmitted to the third reflector through the second lens, and reflected to the electric 1 / 4 wave plate through the third reflector and the fourth reflector.

[0011] In one embodiment of the present invention, the control module includes a computer, a first driving board and a second driving board, the first driving board and the second driving board are both electrically connected to the computer, the electric 1 / 2 wave plate is electrically connected to the first driving board, the spatial light modulator is electrically connected to the first driving board, and the electric 1 / 4 wave plate is electrically connected to the second driving board;

[0012] The computer is used to control the first driving plate to drive the electric 1 / 2 wave plate to rotate, to control the spatial light modulator to perform phase modulation through the first driving plate, and to control the second driving plate to drive the electric 1 / 4 wave plate to rotate.

[0013] In a second aspect, the present invention provides a laser polarization state control method for ultrafast laser processing, which is applied to a laser polarization state control device for ultrafast laser processing provided by the above scheme, wherein the laser polarization state control device comprises an electric 1 / 2 wave plate, a spatial light modulator, an electric 1 / 4 wave plate and a control module, and the method comprises:

[0014] The electric 1 / 2 wave plate is controlled to rotate by the control module;

[0015] Controlling the spatial light modulator to perform phase modulation through a control module;

[0016] The electric quarter wave plate is controlled to rotate by the control module to adjust the polarization state of the laser emitted through the electric quarter wave plate.

[0017] In one embodiment of the present invention, the method specifically includes:

[0018] Establish a three-dimensional coordinate system;

[0019] The fast axis of the electric half-wave plate is controlled by the control module to rotate to an angle of 22.5° with the X-axis;

[0020] The control module controls the spatial light modulator to load the first vortex phase based on the first formula, and the first formula is:

[0021] φ(r,θ,z)=2θ-kz

[0022] Among them, φ(r,θ,z) represents the first vortex phase, r is the radial coordinate, θ is the azimuthal coordinate, z is the axial coordinate, and k represents the wave number;

[0023] The control module controls the fast axis rotation of the electric quarter wave plate to form an angle of 135° with the X axis, so that the polarization state of the laser emitted through the electric quarter wave plate is radial polarization.

[0024] In one embodiment of the present invention, the method specifically includes:

[0025] Establish a three-dimensional coordinate system;

[0026] The fast axis of the electric half-wave plate is controlled by the control module to rotate to an angle of 22.5° with the X-axis;

[0027] Controlling the spatial light modulator to load a second vortex phase through a control module, the second vortex phase rotates 90° clockwise relative to the first vortex phase;

[0028] The control module controls the fast axis rotation of the electric quarter wave plate to form an angle of 135° with the X axis, so that the polarization state of the laser emitted through the electric quarter wave plate is angular polarization.

[0029] In one embodiment of the present invention, the method specifically includes:

[0030] The control module controls the electric 1 / 2 wave plate to rotate and cut out the light path;

[0031] Controlling the spatial light modulator to stop phase modulation through the control module;

[0032] The control module controls the fast axis rotation of the electric quarter wave plate to form an angle of 135° with the X axis, so that the polarization state of the laser emitted through the electric quarter wave plate is circular polarization.

[0033] In one embodiment of the present invention, the method specifically includes:

[0034] The control module controls the electric 1 / 2 wave plate to rotate and cut out the light path;

[0035] Controlling the spatial light modulator to stop phase modulation through the control module;

[0036] The control module controls the electric quarter wave plate to rotate and cut out the light path, so that the polarization state of the laser emitted through the electric quarter wave plate is linear polarization.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] In the above scheme of the present application, the laser polarization state control device includes a laser, an electric 1 / 2 wave plate, a spatial light modulator, a reflector group, an electric 1 / 4 wave plate, a spectroscope, a polarization analyzer system and a control module, the laser and the electric 1 / 2 wave plate are arranged relative to each other, the electric 1 / 4 wave plate and the polarization analyzer system are arranged relative to the spectroscope, and the electric 1 / 2 wave plate, the spatial light modulator and the electric 1 / 4 wave plate are all electrically connected to the control module; the laser light emitted by the laser enters the spatial light modulator through the electric 1 / 2 wave plate, propagates to the reflector group through the spatial light modulator, is reflected to the electric 1 / 4 wave plate through the reflector group, propagates to the spectroscope through the electric 1 / 4 wave plate, and is reflected to the polarization analyzer system through the spectroscope, wherein the laser light transmitted through the spectroscope is used for laser processing, and the control module is used to control the electric 1 / 2 wave plate to rotate, control the spatial light modulator to perform phase modulation, and control the electric 1 / 4 wave plate to rotate, so as to adjust the polarization state of the laser light emitted through the electric 1 / 4 wave plate. With this structure, firstly, by controlling the electric 1 / 2 wave plate to rotate, controlling the spatial light modulator to perform phase modulation, and controlling the electric 1 / 4 wave plate to rotate, the polarization state of the laser can be modulated, so that the laser polarization state control device can achieve dynamic switching of linear polarization, circular polarization, radial polarization, and angular polarization, thereby increasing the adjustable range of the polarization state of the laser beam and the applicable range of the laser polarization state control device. Secondly, by cooperating with the beam splitter and the polarization analyzer system, a part of the laser emitted by the electric 1 / 4 wave plate can be separated and enter the polarization analyzer system for polarization analysis, so that the polarization state of the laser output by the laser polarization state control device can be detected and modulated in real time, ensuring the accuracy of the polarization state.

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram of a laser polarization state control device provided by an embodiment of the present invention;

[0041] Figure 2 is a schematic diagram of an electric half wave plate according to an embodiment of the present invention;

[0042] Figure 3 is a polarization analysis diagram of radial polarization in an embodiment of the present invention;

[0043] Figure 4 It is a polarization analysis diagram of angular polarization in an embodiment of the present invention.

[0044] Figure numerals: 1-laser, 2-beam expander, 3-electric 1 / 2 wave plate, 31-wave plate body, 32-rotating platform, 4-spatial light modulator, 5-first drive plate, 6-first lens, 7-first reflector, 8-second lens, 9-electric 1 / 4 wave plate, 10-beam splitter, 11-electric polarizer, 12-second drive plate, 13-focusing mirror, 14-beam analyzer, 15-polarizer system, 16-optical cavity, 17-processing head, 18-processing platform, 19-computer. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0046] Embodiment 1:

[0047] See also Figure 1 The embodiment of the present invention provides a laser polarization state control device for ultrafast laser processing, comprising a laser 1, an electric 1 / 2 wave plate 3, a spatial light modulator 4, a reflector group, an electric 1 / 4 wave plate 9, a beam splitter 10, a polarization analyzer system 15 and a control module. The laser 1 and the electric 1 / 2 wave plate 3 are arranged opposite to each other, the electric 1 / 4 wave plate 9 and the polarization analyzer system 15 are arranged opposite to the beam splitter 10, and the electric 1 / 2 wave plate 3, the spatial light modulator 4 and the electric 1 / 4 wave plate 9 are all electrically connected to the control module; the laser light emitted by the laser 1 is electrically The 1 / 2 wave plate 3 enters the spatial light modulator 4, propagates to the reflector group through the spatial light modulator 4, is reflected to the electric 1 / 4 wave plate 9 through the reflector group, propagates to the beam splitter 10 through the electric 1 / 4 wave plate 9, and is reflected to the polarization analyzer system 15 through the beam splitter 10, wherein the laser transmitted through the beam splitter 10 is used for laser processing, and the control module is used to control the rotation of the electric 1 / 2 wave plate 3, control the spatial light modulator 4 to perform phase modulation, and control the rotation of the electric 1 / 4 wave plate 9, so as to adjust the polarization state of the laser emitted through the electric 1 / 4 wave plate 9.

[0048] In some embodiments of the present application, the laser 1 may be a femtosecond laser 1. In this way, it is possible to ensure that the pulse width of the laser output by the laser 1 is in the order of picoseconds or femtoseconds, thereby enabling ultrafast laser processing.

[0049] In some embodiments of the present application, the electric 1 / 2 wave plate 3 is an optical element that controls phase delay in an electric manner and is mainly used to change the polarization state of light.

[0050] In some embodiments of the present application, Figure 2As shown, the electric 1 / 2 wave plate 3 may include a rotating platform 32, a wave plate body 31, a first rotating mechanism and a second rotating structure. The rotating platform 32 is provided with a first hole and a second hole. The wave plate body 31 is installed in the first hole. The first rotating mechanism is connected to the wave plate body 31. The first rotating mechanism is used to drive the wave plate body 31 to rotate in the first hole to modulate the polarization state of the light beam. The second rotating structure is used to drive the rotating platform 32 to rotate so that the light beam is emitted through the wave plate body 31 or through the second hole.

[0051] In some embodiments of the present application, the spatial light modulator 4 is a device that can actively control the light field, and loads information into a one-dimensional or two-dimensional light field by modulating parameters such as the amplitude, phase, and polarization state of the light field, and performs rapid processing by utilizing the advantages of wide bandwidth and multi-channel parallel processing of light. The phase of polarized light can be modulated by the spatial light modulator 4.

[0052] In some embodiments of the present application, the electric quarter wave plate 9 is an optical element capable of controlling phase delay by an electrical signal. It is made of birefringent material and the thickness or refractive index of the wave plate is adjusted by changing the voltage or current to control the phase delay of light.

[0053] In some embodiments of the present application, the electric 1 / 4 wave plate 9 may include a rotating platform, a wave plate, a third rotating mechanism and a fourth rotating structure. The rotating platform is provided with a third hole and a fourth hole, the wave plate is installed in the third hole, the third rotating mechanism is connected to the wave plate, the third rotating mechanism is used to drive the wave plate to rotate in the third hole to modulate the polarization state of the light beam, and the fourth rotating structure is used to drive the rotating platform to rotate so that the light beam is emitted through the wave plate or through the fourth hole.

[0054] In some embodiments of the present application, the splitting ratio of the beam splitter 10 can be 99:1. In this way, 1% of the laser energy can be reflected to the polarization analysis system 15 for polarization analysis, and 99% of the laser energy can be used for laser processing, thereby ensuring the efficiency of laser processing.

[0055] In some embodiments of the present application, the laser polarization state control device is used in ultrafast laser processing equipment, which includes an optical cavity 16, a processing head 17 and a supporting platform. A workpiece to be processed is provided on the supporting platform. The laser transmitted through the beam splitter 10 enters the optical cavity 16. A plurality of reflectors are provided in the optical cavity 16. The laser is reflected by the plurality of reflectors to the processing head 17 and is emitted through the processing head 17 to the surface of the workpiece to be processed, thereby realizing ultrafast laser processing of the workpiece.

[0056] In the above scheme of the present application, the laser polarization state control device includes a laser 1, an electric 1 / 2 wave plate 3, a spatial light modulator 4, a reflector group, an electric 1 / 4 wave plate 9, a beam splitter 10, a polarization analyzer system 15 and a control module. The laser 1 and the electric 1 / 2 wave plate 3 are arranged relative to each other, the electric 1 / 4 wave plate 9 and the polarization analyzer system 15 are arranged relative to the beam splitter 10, and the electric 1 / 2 wave plate 3, the spatial light modulator 4 and the electric 1 / 4 wave plate 9 are electrically connected to the control module; the laser light emitted by the laser 1 passes through the electric 1 / 2 wave plate 3 The laser beam enters the spatial light modulator 4, propagates to the reflector group through the spatial light modulator 4, is reflected to the electric 1 / 4 wave plate 9 through the reflector group, propagates to the beam splitter 10 through the electric 1 / 4 wave plate 9, and is reflected to the polarization analyzer system 15 through the beam splitter 10, wherein the laser beam transmitted through the beam splitter 10 is used for laser processing, and the control module is used to control the electric 1 / 2 wave plate 3 to rotate, control the spatial light modulator 4 to perform phase modulation, and control the electric 1 / 4 wave plate 9 to rotate, so as to adjust the polarization state of the laser beam emitted through the electric 1 / 4 wave plate 9. With this structure, firstly, by controlling the electric 1 / 2 wave plate 3 to rotate, controlling the spatial light modulator 4 to perform phase modulation, and controlling the electric 1 / 4 wave plate 9 to rotate, the polarization state of the laser beam can be modulated, so that the laser polarization state control device can realize dynamic switching of linear polarization, circular polarization, radial polarization, and angular polarization, thereby increasing the adjustable range of the polarization state of the laser beam and the applicable range of the laser polarization state control device. Secondly, by cooperating with the beam splitter 10 and the polarization analysis system 15, a part of the laser emitted by the electric 1 / 4 wave plate 9 can be separated and enter the polarization analysis system 15 for polarization analysis, so that the polarization state of the laser output by the laser polarization state control device can be detected and modulated in real time to ensure the accuracy of the polarization state.

[0057] In some embodiments of the present application, the polarization analyzer system 15 includes an electric polarization analyzer 11, a focusing mirror 13, and a beam analyzer 14, which are arranged in sequence. The laser is reflected to the electric polarization analyzer 11 by the beam splitter 10, emitted to the focusing mirror 13 by the electric polarization analyzer 11, and converged to the beam analyzer 14 by the focusing mirror 13. With this structure, the polarization state of the laser can be detected through the cooperation of the electric polarization analyzer 11, the focusing mirror 13, and the beam analyzer 14, thereby ensuring the accuracy of the laser output by the laser polarization state control device.

[0058] In some embodiments of the present application, the electric polarizer 11 is a device that drives the polarizer inside it to rotate electrically to change the polarization state of the transmitted light. It is mainly used to check or adjust the polarization state of light to meet specific optical measurement or communication requirements.

[0059] In some embodiments of the present application, the beam profiler 14 is an analyzer for measuring and evaluating the quality and characteristics of a beam. The beam profiler 14 can provide various parameters about the beam, such as the diameter, divergence angle, and light intensity distribution of the beam.

[0060] In some embodiments of the present application, the laser polarization state control device further includes a beam expander 2, which is disposed between the laser 1 and the electric 1 / 2 wave plate 3. The laser light emitted by the laser 1 is expanded by the beam expander 2 and then enters the electric 1 / 2 wave plate 3. With this structure, the laser light emitted by the laser 1 is expanded by the beam expander 2, so that the diameter and divergence angle of the laser light beam can be changed, thereby improving the collimation and focusing effect of the laser light beam.

[0061] In some embodiments of the present application, the reflector group includes a first lens 6, a first reflector 7, a second reflector, a second lens 8, a third reflector and a fourth reflector, the first lens 6 and the second lens 8 form a 4f system, and the lasers passing through the electric 1 / 2 wave plate 3 and the electric 1 / 4 wave plate 9 are all propagated in the horizontal direction; the laser is emitted to the first lens 6 through the spatial light modulator 4, transmitted to the first reflector 7 through the first lens 6, reflected to the second lens 8 through the first reflector 7 and the second reflector, transmitted to the third reflector through the second lens 8, and reflected to the electric 1 / 4 wave plate 9 through the third reflector and the fourth reflector. With this structure, since the aperture of the spatial light modulator 4 is usually about 10 mm, the incident beam diameter is subject to certain restrictions. When the beam diameter required by the terminal exceeds the modulated aperture, the first lens 6 and the second lens 8 are used to form a 4f system to perform secondary beam expansion on the beam modulated by the spatial light modulator 4, so that the laser output by the laser polarization state control device can meet the processing requirements. In addition, by emitting beams through multiple reflectors, the flexibility of the layout of each component can be improved.

[0062] In some embodiments of the present application, the 4f system is an optical system widely used in the fields of Fourier transform optics, image processing, optical information processing, holography, etc. It consists of two lens groups with the same focal length, each lens group has a focal length of f, and the distance between the two lenses is 4f.

[0063] In some embodiments of the present application, the control module includes a computer 19, a first driving board 5 and a second driving board 12, the first driving board 5 and the second driving board 12 are both electrically connected to the computer 19, the electric 1 / 2 wave plate 3 is electrically connected to the first driving board 5, the spatial light modulator 4 is electrically connected to the first driving board 5, and the electric 1 / 4 wave plate 9 is electrically connected to the second driving board 12; the computer 19 is used to control the first driving board 5 to drive the electric 1 / 2 wave plate 3 to rotate, to control the spatial light modulator 4 to perform phase modulation through the first driving board 5, and to control the second driving board 12 to drive the electric 1 / 4 wave plate 9 to rotate. With this structure, the computer 19 controls the first driving plate 5 to drive the electric 1 / 2 wave plate 3 to rotate, so that the electric 1 / 2 wave plate 3 can modulate the polarization state of the light beam. The computer 19 controls the spatial light modulator 4 to perform phase modulation through the first driving plate 5, so that the spatial light modulator 4 can modulate the polarization state of the light beam. The computer 19 controls the second driving plate 12 to drive the electric 1 / 4 wave plate 9 to rotate, so that the electric 1 / 4 wave plate 9 can modulate the polarization state of the light beam, thereby enabling the laser polarization state control device to achieve dynamic switching of linear polarization, circular polarization, radial polarization and angular polarization.

[0064] In some embodiments of the present application, the driver board is an electronic device that is mainly used to control and drive the operation of other hardware devices. It is usually an important component of a system such as a computer 19, an electronic device or a robot, and plays a role in connecting and controlling various hardware modules. The main functions of the driver board include interface conversion, control signal generation, data transmission and power management. It can convert the electrical signal of the mainboard or other devices into an interface signal suitable for the controlled device, generate corresponding control signals to drive the hardware device to perform specific operations, and perform data transmission between the mainboard and other hardware devices to ensure the correct flow of information.

[0065] Embodiment 2:

[0066] The embodiment of the present invention further provides a laser polarization state control method for ultrafast laser processing, which is applied to the laser polarization state control device for ultrafast laser processing provided in the first embodiment above, wherein the laser polarization state control device includes an electric 1 / 2 wave plate, a spatial light modulator, an electric 1 / 4 wave plate and a control module, and the method includes:

[0067] The electric 1 / 2 wave plate is controlled to rotate by the control module;

[0068] Controlling the spatial light modulator to perform phase modulation through a control module;

[0069] The electric quarter wave plate is controlled to rotate by the control module to adjust the polarization state of the laser emitted through the electric quarter wave plate.

[0070] The beneficial effects of the second embodiment of the present invention and its various implementations can be analyzed by referring to the beneficial effects of the first embodiment and its various implementations, which will not be described in detail here.

[0071] In some embodiments of the present application, the method specifically includes:

[0072] Establish a three-dimensional coordinate system;

[0073] The fast axis of the electric half-wave plate is controlled by the control module to rotate to an angle of 22.5° with the X-axis;

[0074] The control module controls the spatial light modulator to load the first vortex phase based on the first formula, and the first formula is:

[0075] φ(r,θ,z)=2θ-kz

[0076] Among them, φ(r,θ,z) represents the first vortex phase, r is the radial coordinate, θ is the azimuthal coordinate, z is the axial coordinate, and k represents the wave number;

[0077] The control module controls the fast axis rotation of the electric quarter wave plate to form an angle of 135° with the X axis, so that the polarization state of the laser emitted by the electric quarter wave plate is radial polarization. In this way, the polarization state of the laser emitted by the laser polarization state control device can be radial polarization, thereby meeting the use requirements of radial polarization during laser processing.

[0078] In some embodiments of the present application, Figure 3 The radial polarization analyzer diagram is shown in Figure 3 As shown in the figure, after the light beam passes through the analyzer of the electric analyzer, the extinction direction can be observed in the beam analyzer, which is orthogonal to the analysis direction. This proves that the current polarization state is radial polarization. The analysis result is as follows: Figure 3 As shown, the polarization result represents the characteristics of the vortex phase loaded on the spatial light modulator, which carries orbital angular momentum on the basis of conventional angular and radial polarization. Therefore, the angular and radial polarization produced by the present application present an "S" shape during polarization analysis.

[0079] In some embodiments of the present application, the method specifically includes:

[0080] Establish a three-dimensional coordinate system;

[0081] The fast axis of the electric half-wave plate is controlled by the control module to rotate to an angle of 22.5° with the X-axis;

[0082] Controlling the spatial light modulator to load a second vortex phase through a control module, the second vortex phase rotates 90° clockwise relative to the first vortex phase;

[0083] The control module controls the fast axis rotation of the electric quarter wave plate to form an angle of 135° with the X axis, so that the polarization state of the laser emitted by the electric quarter wave plate is angular polarization. In this way, the polarization state of the laser emitted by the laser polarization state control device can be angular polarization, thereby meeting the use requirements of angular polarization during laser processing.

[0084] In some embodiments of the present application, Figure 4 The polarization diagram of the angular polarization is shown in FIG. Figure 4 As shown, after the light beam passes through the analyzer of the electric analyzer, it can be observed in the beam analyzer that the light spot is in the extinction direction along the analysis direction (that is, there is no light intensity in the analysis direction), which proves that the current polarization state is angular polarization.

[0085] In some embodiments of the present application, the method specifically includes:

[0086] The control module controls the electric 1 / 2 wave plate to rotate and cut out the light path;

[0087] Controlling the spatial light modulator to stop phase modulation through the control module;

[0088] The control module controls the fast axis rotation of the electric quarter wave plate to form an angle of 135° with the X axis, so that the polarization state of the laser emitted by the electric quarter wave plate is circular polarization. In this way, the polarization state of the laser emitted by the laser polarization state control device can be circular polarization, thereby meeting the use requirements of circular polarization during laser processing.

[0089] In some embodiments of the present application, the second rotating mechanism in the electric 1 / 2 wave plate can be used to control the rotation of the rotating platform, so that the light beam is emitted through the second hole, thereby enabling the electric 1 / 2 wave plate to rotate to cut out the light path.

[0090] In some embodiments of the present application, when the light beam is reflected by the beam splitter to the analyzer of the electric analyzer, the analyzer is rotated 360 degrees in the analysis direction. At this time, the intensity of the light spot in the beam analyzer does not change, which proves that the polarization state at this time is circular polarization.

[0091] In some embodiments of the present application, the method specifically includes:

[0092] The control module controls the electric 1 / 2 wave plate to rotate and cut out the light path;

[0093] Controlling the spatial light modulator to stop phase modulation through the control module;

[0094] The control module controls the electric quarter wave plate to rotate and cut out the optical path, so that the polarization state of the laser emitted by the electric quarter wave plate is linear polarization. In this way, the polarization state of the laser emitted by the laser polarization state control device can be linear polarization, thereby meeting the use requirements of linear polarization during laser processing.

[0095] In some embodiments of the present application, the fourth rotating mechanism in the electric quarter wave plate can be used to control the rotation of the rotating platform, so that the light beam is emitted through the fourth hole, so that the electric quarter wave plate can be rotated to cut out the light path. When the spatial light modulator stops phase modulation, the spatial light modulator is only used to reflect the light beam.

[0096] In the present invention, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", and "fourth" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0097] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0098] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0099] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A laser polarization state control device for ultrafast laser processing, characterized in that: It includes a laser, an electric 1 / 2 wave plate, a spatial light modulator, a reflector group, an electric 1 / 4 wave plate, a beam splitter, a polarization analyzer system and a control module, wherein the laser and the electric 1 / 2 wave plate are arranged opposite to each other, the electric 1 / 4 wave plate and the polarization analyzer system are arranged opposite to the beam splitter, and the electric 1 / 2 wave plate, the spatial light modulator and the electric 1 / 4 wave plate are electrically connected to the control module; The laser light emitted by the laser enters the spatial light modulator through the electric 1 / 2 wave plate, propagates to the reflector group through the spatial light modulator, is reflected to the electric 1 / 4 wave plate through the reflector group, propagates to the beam splitter through the electric 1 / 4 wave plate, and is reflected to the polarization analyzer system through the beam splitter, wherein the laser light transmitted through the beam splitter is used for laser processing, and the control module is used to control the electric 1 / 2 wave plate to rotate, control the spatial light modulator to perform phase modulation, and control the electric 1 / 4 wave plate to rotate, so as to adjust the polarization state of the laser light emitted through the electric 1 / 4 wave plate.

2. The laser polarization state control device for ultrafast laser processing according to claim 1, characterized in that: The polarization analyzer system includes an electric polarizer, a focusing mirror and a beam analyzer which are arranged in sequence. The laser is reflected to the electric polarizer by the beam splitter, emitted to the focusing mirror by the electric polarizer, and converged to the beam analyzer by the focusing mirror.

3. The laser polarization state control device for ultrafast laser processing according to claim 1, characterized in that: It also includes a beam expander, which is arranged between the laser and the electric 1 / 2 wave plate. The laser light emitted by the laser enters the electric 1 / 2 wave plate after being expanded by the beam expander.

4. The laser polarization state control device for ultrafast laser processing according to claim 1, characterized in that: The reflector group includes a first lens, a first reflector, a second reflector, a second lens, a third reflector and a fourth reflector, the first lens and the second lens form a 4f system, and the lasers passing through the electric 1 / 2 wave plate and the electric 1 / 4 wave plate are both propagated in the horizontal direction; The laser is emitted to the first lens through the spatial light modulator, transmitted to the first reflector through the first lens, reflected to the second lens through the first reflector and the second reflector, transmitted to the third reflector through the second lens, and reflected to the electric 1 / 4 wave plate through the third reflector and the fourth reflector.

5. The laser polarization state control device for ultrafast laser processing according to claim 1, characterized in that: The control module includes a computer, a first driving board and a second driving board, the first driving board and the second driving board are both electrically connected to the computer, the electric 1 / 2 wave plate is electrically connected to the first driving board, the spatial light modulator is electrically connected to the first driving board, and the electric 1 / 4 wave plate is electrically connected to the second driving board; The computer is used to control the first driving board to drive the electric 1 / 2 wave plate to rotate, to control the spatial light modulator to perform phase modulation through the first driving board, and to control the second driving board to drive the electric 1 / 4 wave plate to rotate.

6. A laser polarization state control method for ultrafast laser processing, characterized in that: A laser polarization state control device for ultrafast laser processing according to any one of claims 1 to 5, wherein the laser polarization state control device comprises an electric 1 / 2 wave plate, a spatial light modulator, an electric 1 / 4 wave plate and a control module, and the method comprises: Controlling the electric 1 / 2 wave plate to rotate by the control module; Controlling the spatial light modulator to perform phase modulation by the control module; The electric quarter wave plate is controlled to rotate by the control module to adjust the polarization state of the laser emitted through the electric quarter wave plate.

7. The laser polarization state control method for ultrafast laser processing according to claim 6, characterized in that: The method specifically comprises: Establish a three-dimensional coordinate system; Control the fast axis of the electric half-wave plate to rotate to an angle of 22.5° with the X-axis through the control module; The control module controls the spatial light modulator to load the first vortex phase based on a first formula, wherein the first formula is: φ(r,θ,z)=2θ-kz Among them, φ(r,θ,z) represents the first vortex phase, r is the radial coordinate, θ is the azimuthal coordinate, z is the axial coordinate, and k represents the wave number; The control module controls the fast axis of the electric quarter wave plate to rotate at an angle of 135° with the X axis, so that the polarization state of the laser emitted through the electric quarter wave plate is radial polarization.

8. The laser polarization state control method for ultrafast laser processing according to claim 7, characterized in that: The method specifically comprises: Establish a three-dimensional coordinate system; Control the fast axis of the electric half-wave plate to rotate to an angle of 22.5° with the X-axis through the control module; Controlling the spatial light modulator to load a second vortex phase through the control module, wherein the second vortex phase rotates 90° clockwise relative to the first vortex phase; The control module controls the fast axis of the electric quarter wave plate to rotate at an angle of 135° with the X axis, so that the polarization state of the laser emitted through the electric quarter wave plate is angular polarization.

9. The laser polarization state control method for ultrafast laser processing according to claim 6, characterized in that: The method specifically comprises: Control the electric 1 / 2 wave plate to rotate and cut out the light path through the control module; Controlling the spatial light modulator to stop phase modulation by the control module; The control module controls the fast axis of the electric quarter wave plate to rotate at an angle of 135° with the X axis, so that the polarization state of the laser emitted through the electric quarter wave plate is circular polarization.

10. The laser polarization state control method for ultrafast laser processing according to claim 6, characterized in that: The method specifically comprises: Control the electric 1 / 2 wave plate to rotate and cut out the light path through the control module; Controlling the spatial light modulator to stop phase modulation by the control module; The control module controls the electric quarter wave plate to rotate and cut out the light path, so that the polarization state of the laser emitted through the electric quarter wave plate is linear polarization.

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