Pulse laser timing synthesizer

Abstract

The application discloses a kind of pulse laser timing synthesis devices, the device includes light source module, first birefringent crystal, second birefringent crystal, polarization modulator and timing synchronization controller, three pulse lasers generated by light source module are collimated and placed in parallel according to specific distance, and are combined into a bundle after sequentially passing through first birefringent crystal, polarization modulator and second birefringent crystal.Compared with prior art, the pulse laser timing synthesis device of the application does not involve mechanical moving device, avoids the problem of laser pointing instability caused by mechanical jitter, can realize the timing synthesis of linearly polarized laser or non-linearly polarized laser, has low requirement for laser polarization for synthesis, widens the application range of laser for synthesis, and the birefringent crystal used is particularly suitable for the synthesis of high-power high-beam-quality laser.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a pulsed laser timing synthesis device. Background Technology

[0002] High-power, high-brightness lasers have important applications in industrial manufacturing, scientific research, and national security. However, as laser power increases, beam quality decreases nonlinearly, making it impossible to guarantee laser brightness. Beam combining technology, which can manage heat dissipation, is an important means to solve this problem. Among them, multi-pulse laser temporal coaxial combining technology has advantages such as relatively easy control, high combining efficiency, and good beam quality after combining, making it an important approach to improve laser power and brightness.

[0003] Existing time-series combining techniques mainly include three categories: reflection-based time-series combining, refraction-shifting time-series combining, and polarization-based time-series combining. Reflection-based and refraction-shifting coaxial time-series combining techniques suffer from poor stability due to mechanical jitter caused by the use of mechanical rotation or oscillation devices, which increases the pointing jitter of the synthesized beam. Existing polarization-based time-series combining methods have high requirements for the polarization of the synthesized sub-lasers, limiting the range of applicable synthesized sub-lasers.

[0004] Therefore, there is an urgent need for a synthesis pulse timing synthesis device that can improve the pointing stability of the synthesized beam and meet the requirements of lasers with various polarization types. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] The purpose of this invention is to overcome the problems of existing pulsed laser timing synthesis technology being greatly affected by mechanical jitter and having high requirements for the polarization of synthesized sub-lasers, and to propose a new pulsed laser timing synthesis device.

[0007] (II) Technical Solution

[0008] To address at least one of the aforementioned technical problems, this invention provides a pulsed laser timing synthesis device. Combining the characteristics of pulsed lasers and the transmission law of lasers in birefringent crystals, a device capable of timing synthesis of two linearly polarized beams and one arbitrary polarized beam of light is designed. The structure and performance parameters of key components such as the birefringent crystal included in the device are studied and designed.

[0009] This invention provides a pulsed laser timing synthesis device, comprising: a light source module, a first birefringent crystal, a polarization modulator, and a second birefringent crystal arranged sequentially along the optical path, and further comprising a timing synchronization controller;

[0010] The light source module generates three parallel sub-lasers: a first sub-laser, a second sub-laser, and a third sub-laser. These three sub-lasers are located in the same incident plane, with the second sub-laser positioned between the first and third sub-lasers. The distance between adjacent sub-lasers is D. The first and third sub-lasers are linearly polarized light with orthogonal polarization directions. The timing synchronization controller controls the pulse time delay of the first, second, and third sub-lasers. The pulses of the first and third sub-lasers have no time delay, while the pulses of the second sub-laser have a specific delay Δt with the first and third sub-lasers.

[0011] A first birefringent crystal has a first plane and a second plane arranged opposite to each other. A first sub-laser, a second sub-laser, and a third sub-laser are incident perpendicularly to the first plane. The polarization components of the first sub-laser and the second sub-laser are combined to form a first-level composite beam that exits from the second plane. The third sub-laser is combined with another polarization component of the second sub-laser to form a second-level composite beam that exits from the second plane. A timing synchronization controller controls the polarization modulator to modulate the first-level composite beam and the second-level composite beam entering the polarization modulator to form a third-level composite beam and a fourth-level composite beam. The third-level composite beam and the fourth-level composite beam are both linearly polarized light and their polarization directions are orthogonal.

[0012] The second birefringent crystal has a third plane and a fourth plane arranged opposite to each other. The third secondary composite beam and the fourth secondary composite beam are incident perpendicularly to the third plane. One of the secondary composite beams is deflected to the other secondary composite beam and then combined to form the main composite laser beam, which exits from the fourth plane.

[0013] Optionally, the first birefringent crystal is a negative uniaxial birefringent crystal or a positive uniaxial birefringent crystal; the angle between the optical axis of the first birefringent crystal and the first plane is β1, the optical axis of the first birefringent crystal is parallel to the plane defined by the first sub-laser, the second sub-laser, and the third sub-laser, the distance between the first plane and the second plane is d1, and the distance between adjacent sub-lasers is D, which should satisfy:

[0014]

[0015] Where, n o1 n is the refractive index of the o-ray inside the first birefringent crystal. e1 Let be the e-ray refractive index inside the first birefringent crystal.

[0016] Optionally, the second birefringent crystal is a negative uniaxial birefringent crystal or a positive uniaxial birefringent crystal; the angle between the optical axis of the second birefringent crystal and the third plane is β2, the optical axis of the second birefringent crystal is parallel to the plane determined by the first sub-laser, the second sub-laser, and the third sub-laser, and the distance between the third plane and the fourth plane is d2, satisfying:

[0017]

[0018] Where, n o2 n is the refractive index of the o-ray inside the second birefringent crystal. e2 is the e-ray refractive index inside the second birefringent crystal.

[0019] Optionally, the light source module includes a sub-laser emitting unit and a beam spacing and pointing control unit. The sub-laser emitting unit includes at least two sub-lasers for emitting lasers, and the beam spacing and pointing control unit is used to adjust the lasers emitted by the sub-laser emitting unit to form a first sub-laser, a second sub-laser, and a third sub-laser.

[0020] Optionally, the sub-laser emitting unit includes two sub-lasers that generate two laser beams. The beam spacing and pointing control unit includes a polarizing beam splitter to split the laser beam generated by one of the lasers, forming the first sub-laser and the third sub-laser.

[0021] Optionally, the sub-laser emitting unit includes four sub-lasers that generate four linearly polarized laser beams. The beam spacing and pointing control unit includes a polarization beam combiner to combine the polarized laser beams generated by two of the lasers to form the second sub-laser.

[0022] Optionally, the pulse width τ and repetition frequency f of the first, second, and third sub-lasers are all the same, and a specific time delay Δt should satisfy: τ < Δt < 1 / f.

[0023] Optionally, the sub-laser includes one or more of pulse-emitting fiber lasers, solid-state lasers, semiconductor lasers, and gas lasers.

[0024] Optionally, the first birefringent crystal and the second birefringent crystal are uniaxial crystals with a birefringence coefficient greater than 0.1; the first birefringent crystal and the second birefringent crystal include yttrium vanadate or Iceland spar.

[0025] Optionally, the polarization modulator includes at least one of an electro-optic modulator, an acousto-optic modulator, and a magneto-optic modulator.

[0026] (III) Beneficial Effects

[0027] This invention provides a pulsed laser timing synthesis device. A first, second, and third sub-laser generated by a light source module are incident parallel to a first birefringent crystal. After modulation by a timing synchronization controller and a polarization modulator, the resulting secondary synthesized beam is incident parallel to a second birefringent crystal, and then combined to form the main synthesized laser beam. This invention eliminates the use of mechanically rotating reflective or refractive devices, avoiding beam pointing jitter caused by mechanical movement during pulsed timing synthesis, thus improving laser synthesis stability. The pulsed laser timing synthesis device of this invention has low polarization requirements for the synthesized sub-lasers, broadening its applicability. The device also offers easy pointing control of the sub-laser beams; the fabrication of the birefringent crystal only involves parallel processing of the incident and exit planes, making it relatively easy to implement and suitable for high-power, high-beam-quality pulsed laser timing synthesis.

[0028] In a preferred embodiment of the present invention, the first and third sub-lasers generated by the light source module originate from a laser with arbitrary polarization output, and the second sub-laser generated by the light source module originates from another sub-laser with arbitrary polarization output. This scheme is applicable to pulse timing synthesis of two lasers with arbitrary polarization output, and has no requirements on the polarization direction of the laser output from the sub-lasers.

[0029] In another preferred embodiment of the present invention, the first and third sub-lasers generated by the light source module originate from two linearly polarized output sub-lasers, respectively, and the second sub-laser generated by the light source module originates from two other linearly polarized output lasers. This scheme is applicable to pulse timing synthesis of four linearly polarized output lasers. Compared with existing polarization timing synthesis techniques, the number of sub-laser paths that can be synthesized is doubled under the same duty cycle of the main synthesized laser beam, thus facilitating the synthesis of multi-line polarized sub-lasers. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0031] Figure 1 This is a schematic diagram of the pulsed laser timing synthesis device provided by the present invention.

[0032] Figure 2 This is a schematic diagram of the internal beam transmission when the first birefringent crystal in this invention is a positive uniaxial crystal.

[0033] Figure 3 This is a schematic diagram of the internal beam transmission when the second birefringent crystal in this invention is a negative uniaxial crystal.

[0034] Figure 4This is a schematic diagram of the internal beam transmission when the second birefringent crystal in this invention is a positive uniaxial crystal.

[0035] Figure 5 This is a schematic diagram of the internal beam transmission when the second birefringent crystal in this invention is a negative uniaxial crystal.

[0036] Figure 6 This is a schematic diagram of a pulse timing synthesis device for two linearly polarized lasers and one arbitrarily polarized laser, provided in Embodiment 1 of the present invention.

[0037] Figure 7 This is a schematic diagram of a pulse timing synthesis device for two arbitrary polarized lasers provided in Embodiment 2 of the present invention.

[0038] Figure 8 This is a schematic diagram of a pulse timing synthesis device for four linearly polarized lasers provided in Embodiment 3 of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention.

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] This invention provides a pulsed laser timing synthesis device, such as... Figure 1 As shown, it includes a light source module 1, a first birefringent crystal 2, a polarization modulator 3, and a second birefringent crystal 4 arranged sequentially along the incident light path, and also includes a timing synchronization controller 5.

[0043] The light source module 1 is used to generate three parallel sub-lasers: a first sub-laser, a second sub-laser, and a third sub-laser. The first, second, and third sub-lasers are located in the same incident plane, with the second sub-laser located between the first and third sub-lasers. The distance between adjacent sub-lasers is D. The first and third sub-lasers are linearly polarized light with orthogonal polarization directions. Figure 1 In this example, the polarization directions of the first and third sub-lasers are either parallel to the incident plane (P-polarized light) or perpendicular to the incident plane (S-polarized light). The polarization direction of the second sub-laser is not limited; it can be linearly polarized or non-linearly polarized light, such as linearly polarized light, circularly polarized light, elliptically polarized light, or natural light.

[0044] The timing synchronization controller 5 is used to control the pulse time delay of the first, second, and third sub-lasers. It can also control the pulse width and repetition frequency of the three sub-lasers. The pulses of the first and third sub-lasers have no time delay, while the second sub-laser has a specific delay Δt with respect to the first and third sub-lasers. In some embodiments, the first, second, and third sub-lasers have the same pulse width τ and repetition frequency f. The time delay Δt between the pulses of the second sub-laser and the first and third sub-lasers should be as large as possible greater than the pulse width τ and less than the reciprocal of the pulse repetition frequency, 1 / f. The existence of the time delay Δt between the pulses of the second sub-laser and the first and third sub-lasers makes subsequent timing synthesis possible.

[0045] The first birefringent crystal 2 has a first plane and a second plane arranged opposite to each other. Other surfaces of the first birefringent crystal 2 are not limited and can be planar, curved, or multifaceted. In some embodiments, the first birefringent crystal 2 can be a cuboid structure. A first sub-laser, a second sub-laser, and a third sub-laser are incident perpendicularly to the first plane. The polarization components of the first and second sub-lasers are combined to form a first-order composite beam that exits from the second plane. The third sub-laser is combined with another polarization component of the second sub-laser to form a second-order composite beam that exits from the second plane. The first sub-laser is S-polarized light, which propagates as o-light within the first birefringent crystal 2 without changing its propagation direction. After passing through the first birefringent crystal 2, it still exits as S-polarized light. The second sub-laser can be any polarized pulsed laser, such as linearly polarized light, circularly polarized light, or natural light. When passing through the first birefringent crystal 2, the S-polarized component of the second sub-laser propagates as o-light without changing its propagation direction, while the P-polarized component propagates as e-light, with its propagation direction deflected. The propagation process of the second sub-laser within the first birefringent crystal 2 can be referred to... Figure 2 and Figure 3After passing through the first birefringent crystal 2, the light is split into a second sub-laser S-polarized component and a second sub-laser P-polarized component with a spacing of D. The second sub-laser S-polarized component corresponds to the o-ray propagating inside the crystal and has no displacement relative to the incident light. The second sub-laser P-polarized component corresponds to the e-ray propagating inside the crystal and is shifted a distance D relative to the incident light towards the first sub-laser, thus spatially combining with the first sub-laser to form the first-order composite beam. It should be noted that when the second sub-laser is natural light, circularly polarized light, or elliptically polarized light, it propagates within the first birefringent crystal 2 with e-ray and o-ray components orthogonally polarized; when the second sub-laser is P-polarized light, its o-ray component within the first birefringent crystal is zero; and when the second sub-laser is S-polarized light, its e-ray component within the first birefringent crystal is zero. The third sub-laser is P-polarized light, which is transmitted as e-light in the first birefringent crystal 2, and its transmission direction is deflected. After passing through the first birefringent crystal 2, the third sub-laser is shifted by a distance D in the direction of the second sub-laser, and is spatially combined with the S-polarized component of the second sub-laser to form a second-order composite beam.

[0046] The timing synchronization controller 5 controls the polarization modulator 3 to modulate the first-stage and second-stage composite beams entering the polarization modulator 3, forming a third-stage and a fourth-stage composite beam. Both the third-stage and fourth-stage composite beams are linearly polarized light with orthogonal polarization directions. The polarization modulator 3 is a periodically operating polarization modulator, which, based on its working principle, can be classified as an electro-optic modulator, an acousto-optic modulator, or a magneto-optic modulator. It includes an internal modulation crystal and an external driving unit. Under the control of the timing synchronization controller 5, the external driving unit drives the internal modulation crystal to periodically turn polarization modulation on and off. The polarization modulator 3 has a specific modulation frequency, modulation pulse duration, and switching time. Its modulation frequency can be an integer multiple of the sub-laser pulse repetition frequency, its modulation pulse duration should be longer than the sub-laser pulse width, and its switching time should be as short as possible to facilitate the synthesis of shorter pulse width lasers. In some preferred embodiments, the modulation frequency of the polarization modulator 3 is equal to the sub-laser pulse repetition frequency. When the second sub-laser passes through polarization modulator 3, polarization modulator 3 is in the off state under the control of timing synchronization controller 5, and the polarization direction of each polarization component of the second sub-laser remains unchanged. When the first and third sub-lasers pass through, polarization modulator 3 is in the on state under the control of timing synchronization controller 5, and the polarization direction of the first and third sub-lasers is deflected by 90°. After modulation by polarization modulator 3, the first-stage composite beam forms a third-stage composite beam with all pulses having the same polarization direction, and the second-stage composite beam forms a fourth-stage composite beam with all pulses having the same polarization direction.

[0047] The second birefringent crystal 4 has a third plane and a fourth plane arranged opposite to each other. Other surfaces of the second birefringent crystal 4 are not limited and can be planar, curved, or multifaceted. In some embodiments, the second birefringent crystal 4 can be a cuboid structure. The third-order combined beam and the fourth-order combined beam are incident perpendicularly to the third plane, with one secondary combined beam deflected towards the other and then combined to form the main combined laser beam 6, which exits from the fourth plane. The second birefringent crystal 4 is used to combine the incident third-order combined beam and the fourth-order combined beam into the main combined laser beam 6. The distance between the third-order combined beam and the fourth-order combined beam is D, and their polarization directions are orthogonal. The main combined laser beam 6 has twice the pulse repetition frequency and twice the duty cycle compared to the first, second, and third sub-lasers, and its average power is a linear superposition of the powers of the first, second, and third sub-lasers.

[0048] In this invention, the sub-laser beam generated by the light source module 1 is incident parallel to the first birefringent crystal 2. After modulation by the synchronization controller 5 and the polarization modulator 3, the resulting secondary composite beam is incident parallel to the second birefringent crystal 4, and then combined to form the main composite laser beam 6. The pointing control of the sub-laser beam is easy, and the fabrication of the birefringent crystal only involves parallel fabrication of the incident and exit planes, making implementation relatively simple. The pulsed laser timing synthesis device provided by this invention can be used for the synthesis of both linearly polarized and non-linearly polarized lasers, greatly expanding the range of applicable sub-lasers. This invention's device does not use reflective or refractive devices requiring mechanical rotation, avoiding beam pointing jitter caused by mechanical motion devices during pulsed timing synthesis, thus improving laser synthesis stability. The pulsed laser timing synthesis device of this invention is particularly suitable for high-power, high-beam-quality pulsed laser timing synthesis.

[0049] The first birefringent crystal 2 can be a negative uniaxial birefringent crystal or a positive uniaxial birefringent crystal. When the first birefringent crystal 2 is a positive uniaxial birefringent crystal, its internal optical transmission path is as follows: Figure 2 As shown in the figure, the dashed line represents the optical axis, and the e-ray is closer to the optical axis than the o-ray. When the first birefringent crystal 2 is a negative uniaxial birefringent crystal, its internal optical transmission path is as follows: Figure 3 As shown in the figure, the dashed line represents the optical axis direction, and the e-ray is farther away from the optical axis than the o-ray.

[0050] The angle between the optical axis of the first birefringent crystal 2 and the first plane is β1. The optical axis of the first birefringent crystal 2 is parallel to the plane defined by the first sub-laser, the second sub-laser, and the third sub-laser. When the laser is incident perpendicularly on the first birefringent crystal 2, the relationship between the angle α1 and β1 between the e-ray and o-ray inside the first birefringent crystal 2 is as follows:

[0051]

[0052] Where, n 01 n is the refractive index of the o-ray inside the first birefringent crystal 2. e1 denoted as e-ray refractive index inside the first birefringent crystal 2.

[0053] The distance between the first plane and the second plane of the first birefringent crystal 2 is d1, and the distance D between adjacent sub-lasers should satisfy:

[0054] D=d1·tanα1

[0055] Therefore, the distance D between adjacent sub-lasers incident perpendicularly to the first birefringent crystal 2 is:

[0056]

[0057] In some preferred embodiments, to facilitate adjustment of the optical paths of adjacent sub-lasers, the spacing D of the three sub-lasers incident perpendicularly to the first birefringent crystal 2 should be maximized, and the angle β1 between the optical axis and the first plane should satisfy:

[0058] tanβ1=n o1 / n e1

[0059] At this point, the angle α1 between the e-ray and o-ray inside the first birefringent crystal is the maximum discrete angle α. M1

[0060]

[0061] At this point, the maximum sub-laser spacing D is:

[0062]

[0063] The spacing distance D is determined by the distance d1 between the first and second planes and the maximum discrete angle α of the selected birefringent crystal. M1 A joint decision.

[0064] The second birefringent crystal 4 is either a negative uniaxial birefringent crystal or a positive uniaxial birefringent crystal; when the second birefringent crystal 4 is a positive uniaxial birefringent crystal, its internal optical transmission path is as follows: Figure 4 As shown in the figure, the dashed line represents the optical axis, and the e-ray is closer to the optical axis than the o-ray. When the second birefringent crystal 4 is a negative uniaxial birefringent crystal, its internal optical transmission path is as follows: Figure 5 As shown in the figure, the dashed line represents the optical axis direction, and the e-ray is farther away from the optical axis than the o-ray.

[0065] The angle between the optical axis of the second birefringent crystal 4 and the third plane is β2. The optical axis of the second birefringent crystal is parallel to the plane defined by the first, second, and third sub-lasers. When the laser is incident perpendicularly on the second birefringent crystal 4, the relationship between the angles α2 and β2 between the e-ray and o-ray inside the second birefringent crystal 4 is as follows:

[0066]

[0067] Where, n o2 n is the refractive index of the o-ray inside the second birefringent crystal 4. e2 The refractive index of the e-ray inside the second birefringent crystal 4 is given.

[0068] Since the distance D between the third-order and fourth-order composite beams incident perpendicularly to the second birefringent crystal 4 is fixed, the distance d2 between the third and fourth planes is correspondingly determined as follows:

[0069] d2=D / tanα2

[0070] The distance between the third plane and the fourth plane is d2, given by D, β2, and n. o2 n e2 It was determined to be:

[0071]

[0072] In some preferred embodiments, the angle β2 between the optical axis of the second birefringent crystal 4 and the third plane satisfies:

[0073] tanβ2=n o2 / n e2

[0074] At this point, the angle α2 between the e-ray and o-ray inside the second birefringent crystal is the maximum discrete angle α. M2

[0075]

[0076] Since the distance between the third-order and fourth-order combined beams incident perpendicularly to the second birefringent crystal 4 is the same as the distance D between adjacent sub-lasers, the length d2 of the second birefringent crystal 4 is...

[0077]

[0078] In some embodiments, the light source module 1 includes a sub-laser emitting unit 11 and a beam spacing and pointing control unit 12. The sub-laser emitting unit 11 includes at least two sub-lasers for emitting lasers, and the beam spacing and pointing control unit 12 is used to adjust the lasers emitted by the sub-laser emitting unit to form a first sub-laser, a second sub-laser, and a third sub-laser.

[0079] In one specific embodiment, such as Figure 6 As shown, the sub-laser emitting unit 11 includes three sub-lasers, generating three laser beams. The beam spacing and pointing control unit 12 includes a 45° reflector to adjust the pointing and spacing of the laser beams generated by two of the sub-lasers, forming a first sub-laser and a third sub-laser. In this embodiment, two of the three sub-lasers output linearly polarized light, while the polarization direction of the laser beam output by the third sub-laser is not required and can be arbitrarily polarized light.

[0080] In another specific embodiment, such as Figure 7 As shown, the sub-laser emitting unit 11 includes two sub-lasers that generate two laser beams. The beam spacing and pointing control unit 12 includes a polarization beam splitter to split the laser beam generated by one of the sub-lasers, forming a first sub-laser and a third sub-laser. This embodiment does not require the polarization direction of the laser output from the two sub-lasers; it can be any polarized light, such as natural light, circularly polarized light, elliptically polarized light, linearly polarized light, etc., and is particularly suitable for pulse timing synthesis of two lasers with arbitrary polarization output.

[0081] In yet another specific embodiment, such as Figure 8 As shown, the sub-laser emitting unit 11 includes four sub-lasers, generating four linearly polarized laser beams. The beam spacing and pointing control unit 12 includes a polarization combiner to combine the linearly polarized laser beams generated by two of the sub-lasers to form a second sub-laser. This embodiment is suitable for pulse timing synthesis of four linearly polarized output lasers. Compared with existing polarization timing synthesis techniques, the number of sub-laser paths that can be synthesized is doubled under the same duty cycle of the main synthesized laser beam, thus facilitating the synthesis of multi-line polarized sub-lasers.

[0082] In some embodiments, the sub-laser emitting unit 11 may include one or more of the following: a pulse-emitting fiber laser, a solid-state laser, a semiconductor laser, and a gas laser.

[0083] In some embodiments, the first and second birefringent crystals are uniaxial crystals with a birefringence greater than 0.1, such as yttrium vanadate (YVO4) and Iceland spar. Because the birefringent crystal has a finite length and a birefringence greater than 0.1, it ensures a large angle between the e-ray and o-ray within the crystal, thus enabling the pulse-time synthesis of sub-lasers with a larger interval D.

[0084] In some embodiments, the polarization modulator 3 includes at least one of an electro-optic modulator, an acousto-optic modulator, and a magneto-optic modulator, which selectively modulates the polarization direction of the incident light by 90°.

[0085] The pulsed laser timing synthesis apparatus provided by the present invention will be described below through specific embodiments.

[0086] Example 1

[0087] For a schematic diagram of the specific device in this embodiment, please refer to [link / reference]. Figure 6 The figure is a schematic diagram of a pulse timing synthesis device for two linearly polarized lasers and one arbitrarily polarized laser.

[0088] This embodiment includes a light source module 1, a first birefringent crystal 2, a polarization modulator 3, a second birefringent crystal 4, and a timing synchronization controller 5;

[0089] like Figure 6 As shown, the light source module 1 consists of a sub-laser emitting unit 11 and a beam spacing and pointing control unit 12. The sub-laser emitting unit 11 includes three horizontally placed pulsed sodium beacon sub-lasers 111, 112 and 113, and the beam spacing and pointing control unit 12 includes 45° reflectors 1201, 1202, 1203 and 1204;

[0090] The sub-laser emitting unit 11 preferably, but not necessarily, consists of three 589nm pulsed sodium beacon sub-lasers. Sub-laser 111 outputs S-polarized light with a spot diameter of 3mm, an average output power of 50W, a repetition frequency f of 500Hz, and a pulse width τ of 100μs. Sub-laser 112 outputs arbitrary polarized light with a spot diameter of 3mm, an average output power of 50W, a repetition frequency f of 500Hz, and a pulse width τ of 100μs. Sub-laser 113 outputs P-polarized light with a spot diameter of 3mm, an average output power of 50W, a repetition frequency f of 500Hz, and a pulse width τ of 100μs.

[0091] Both the first birefringent crystal 2 and the second birefringent crystal 4 are negative uniaxial YVO4 (yttrium vanadate) crystals. For a 589nm wavelength laser, the e-ray refractive index n of the YVO4 crystal is... e The o-ray refractive index n of YVO4 crystal is 2.2154. o The value is 1.9929, and the birefringence coefficient Δn is 0.2225. In this embodiment, the angle β1 between the optical axis of the first birefringent crystal 2 and the first plane is 41.97°, and β1 satisfies: tanβ1=n o1 / n e1 The angle between the e-ray and the o-ray is the maximum discrete angle α. M1 α M1 It equals 6.05°. The angle β2 between the optical axis of the second birefringent crystal 4 and the incident end face is 41.97°, satisfying: tanβ2=n o2 / n e2 The angle between the e-ray and the o-ray is the maximum discrete angle α. M2 α M2It equals 6.05°. Both the first birefringent crystal 2 and the second birefringent crystal 4 are cut into cuboid shapes, with a length d of 10cm along the light transmission direction, an incident end face width of 5cm, and a thickness of 1cm.

[0092] In this embodiment, the polarization modulator 3 used is an electro-optic modulator.

[0093] Under the control of the timing synthesis synchronization control system 5, the relative time delay between sub-lasers 111 and 113 is zero (the delay is much smaller than the pulse width), and the relative time delay Δt between sub-lasers 112 and sub-lasers 111 and 113 is 1 ms. The second sub-laser emitted by sub-laser 112 is incident perpendicularly to the first birefringent crystal 2. After being adjusted by 45° reflectors 1201 and 1202, the laser emitted by sub-laser 111 forms a first sub-laser whose beam direction and horizontal height are consistent with the second sub-laser emitted by sub-laser 112, and the horizontal distance D between the first and second sub-lasers is 10.6 mm. After being adjusted by 45° reflectors 1203 and 1204, the laser emitted by sub-laser 113 forms a third sub-laser whose beam direction and horizontal height are consistent with the second sub-laser emitted by sub-laser 112, and the horizontal distance D between the third and second sub-lasers is 10.6 mm.

[0094] After passing through the first birefringent crystal 2, neither the first sub-laser nor the second sub-laser's S-polarized component light is displaced relative to the incident light. The second sub-laser is split into two components, P-polarized and S-polarized. The second sub-laser's P-polarized component light is shifted a distance D relative to the incident light towards the first sub-laser, and spatially combines with the first sub-laser to form the first-order composite beam. The third sub-laser is shifted a distance D relative to the incident light towards the second sub-laser, and spatially combines with the second sub-laser's S-polarized component light to form the second-order composite beam.

[0095] Under the control of the timing synthesis synchronization control system 5, the polarization modulator 3 rotates the polarization directions of the first and third sub-lasers by 90°, while the polarization directions of each polarization component of the second sub-laser remain unchanged. After passing through the exit surface of the polarization modulator 3, the first-stage synthesized beam and the second-stage synthesized beam form the third-stage synthesized beam and the fourth-stage synthesized beam, wherein both the third-stage synthesized beam and the fourth-stage synthesized beam are linearly polarized light with orthogonal polarization directions.

[0096] The third and fourth secondary composite beams, with orthogonal polarization directions, are incident perpendicularly on the second birefringent crystal 4. One of the secondary composite beams is deflected towards the other and then combined to form the main composite laser beam 6. The resulting main beam 6 is a combined pulsed sodium beacon laser with an average power of 150W and a repetition frequency of 1kHz.

[0097] This embodiment provides a timing synthesis device for two linearly polarized laser beams and one arbitraryly polarized laser beam. It combines beam splitting and combining techniques using birefringent crystals with existing polarization timing synthesis techniques to achieve the synthesis of two low-average-power linearly polarized laser beams and one low-average-power arbitraryly polarized laser beam. This invention synthesizes three laser beams at once, and does not require specific polarization direction for one of the beams, making it applicable to scenarios involving more beam synthesis.

[0098] Example 2

[0099] For a schematic diagram of the specific device in this embodiment, please refer to [link / reference]. Figure 7 The figure shows a schematic diagram of a pulse timing synthesis device for two arbitrary polarized lasers. The structure of the device provided in this embodiment is basically the same as that of the device provided in Embodiment 1, except that:

[0100] 1. The sub-laser emitting unit 11 and the beam spacing and pointing control unit 12 in the light source module 1 have different configurations. The sub-laser emitting unit 11 is composed of sub-lasers 114 and 115, and the beam spacing and pointing control unit 12 is composed of 45° reflectors 1205, 1206, 1208 and polarizing beam splitter 1207.

[0101] 2. The polarization directions of sub-lasers 114 and 115 can be arbitrary and are not required.

[0102] 3. In this embodiment, the second sub-laser emitted by sub-laser 114 is incident perpendicularly to the first birefringent crystal 2. The laser emitted by sub-laser 115 is incident on polarizing beam splitter 1207 after being adjusted by 45° reflectors 1205 and 1206. After being split by polarizing beam splitter 1207, the P-polarized component light forms the third sub-laser, and the S-polarized component light path reflector 1208 is adjusted in terms of spacing and direction to form the third sub-laser.

[0103] 4. The sub-laser emitting unit 11 preferably, but not necessarily, consists of two 589nm pulsed sodium beacon sub-lasers. Sub-laser 114 outputs arbitrary polarized light with a spot diameter of 3mm, an average output power of 50W, a repetition frequency f of 500Hz, and a pulse width τ of 100μs. Sub-laser 115 outputs arbitrary polarized light with a spot diameter of 3mm, an average output power of 50W, a repetition frequency f of 500Hz, and a pulse width τ of 100μs.

[0104] 5. Under the control of the timing synthesis synchronization control system 5, the relative time delay Δt between sub-lasers 114 and 115 is 1ms.

[0105] 6. In this embodiment, the synthesized main beam 6 is a synthesized pulsed sodium beacon laser with an average power of 100W and a repetition frequency of 1kHz.

[0106] This embodiment provides a timing synthesis device for two pulsed sub-lasers with arbitrary polarization. It does not require the polarization direction of the laser emitted by the sub-laser used for synthesis, which greatly expands the range of applicable sub-lasers.

[0107] Example 3

[0108] For a schematic diagram of the specific device in this embodiment, please refer to [link / reference]. Figure 8 The figure shows a schematic diagram of a pulse timing synthesis device for four linearly polarized lasers. The structure of the device provided in this embodiment is basically the same as that of the device provided in Embodiment 1, except that:

[0109] 1. The sub-laser emitting unit 11 and the beam spacing and pointing control unit 12 in the light source module 1 have different configurations. The sub-laser emitting unit 11 is composed of sub-lasers 116, 117, 118 and 119. The beam spacing and pointing control unit 12 is composed of reflectors 1209, 1210, 1211, 1212, 1213, 1215, 1216 and polarizing beam combiner 1214 placed at 45° to the horizontal direction.

[0110] 2. The lasers emitted by sub-lasers 116, 117, 118 and 119 are all linearly polarized light.

[0111] 3. In this embodiment, the laser emitted by sub-laser 116 is adjusted by 45° reflectors 1201 and 1202 to form a first sub-laser; the laser emitted by sub-laser 117 and sub-laser 118 are adjusted in spacing and direction by 45° reflectors 1211, 1212 and 1213 before being incident on polarization combiner 1214, where they are combined to form a second sub-laser; the laser emitted by sub-laser 119 is adjusted by 45° reflectors 1215 and 1216 to form a third sub-laser. The spacing D between adjacent sub-lasers is 10.6 mm.

[0112] 4. The sub-laser emitting unit 11 preferably, but not necessarily, consists of four 589nm pulsed sodium beacon sub-lasers. Sub-laser 116 outputs S-polarized light with a spot diameter of 3mm, an average output power of 50W, a repetition frequency f of 500Hz, and a pulse width τ of 100μs. Sub-laser 117 outputs P-polarized light with a spot diameter of 3mm, an average output power of 50W, a repetition frequency f of 500Hz, and a pulse width τ of 100μs. Sub-laser 118 outputs S-polarized light with a spot diameter of 3mm, an average output power of 50W, a repetition frequency f of 500Hz, and a pulse width τ of 100μs. Sub-laser 119 outputs P-polarized light with a spot diameter of 3mm, an average output power of 50W, a repetition frequency f of 500Hz, and a pulse width τ of 100μs.

[0113] 5. Under the control of the timing synthesis synchronization control system 5, the relative time delay of sub-lasers 116 and 119 is zero (the delay is much smaller than the pulse width), the relative time delay of sub-lasers 117 and 118 is zero (the delay is much smaller than the pulse width), and the relative time delay Δt between sub-lasers 116, 119 and sub-lasers 117, 118 is 1ms.

[0114] 6. In this embodiment, the synthesized main beam 6 is a synthesized pulsed sodium beacon laser with an average power of 200W and a repetition frequency of 1kHz.

[0115] This embodiment provides a timing synthesis device for four linearly polarized pulsed lasers. The first and second sub-lasers generated by the light source module originate from two linearly polarized lasers, respectively, while the second sub-laser generated by the light source module originates from a polarization combiner of two other linearly polarized lasers. This scheme achieves the synthesis of four linearly polarized lasers. Compared with existing polarization timing synthesis techniques, it doubles the number of synthesized sub-lasers at the same duty cycle, thus facilitating the synthesis of more linearly polarized laser beams.

[0116] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A pulse laser timing synthesizer apparatus, comprising: include: The light source module, the first birefringent crystal, the polarization modulator, and the second birefringent crystal are arranged sequentially along the optical path, and a timing synchronization controller is also included. The light source module generates three parallel sub-lasers: a first sub-laser, a second sub-laser, and a third sub-laser. These three sub-lasers are located in the same incident plane, with the second sub-laser positioned between the first and third sub-lasers. The distance between adjacent sub-lasers is D. The first and third sub-lasers are linearly polarized light with orthogonal polarization directions, while the second sub-laser is non-linearly polarized light. The timing synchronization controller controls the pulse time delay of the first, second, and third sub-lasers. The pulses of the first and third sub-lasers have no time delay, while the pulses of the second sub-laser have a specific time delay with the first and third sub-lasers. ; The first birefringent crystal has a first plane and a second plane arranged opposite to each other. The first sub-laser, the second sub-laser, and the third sub-laser are incident perpendicularly to the first plane. The polarization components of the first sub-laser and the second sub-laser are combined to form a first-level composite beam that exits from the second plane. The third sub-laser is combined with another polarization component of the second sub-laser to form a second-level composite beam that exits from the second plane. The timing synchronization controller controls the polarization modulator to modulate the first-level composite beam and the second-level composite beam entering the polarization modulator to form a third-level composite beam and a fourth-level composite beam. The third-level composite beam and the fourth-level composite beam are both linearly polarized light and their polarization directions are orthogonal. The second birefringent crystal has a third plane and a fourth plane arranged opposite to each other. The third secondary composite beam and the fourth secondary composite beam are incident perpendicularly to the third plane. One secondary composite beam is deflected to the other secondary composite beam and then combined to form a main composite laser beam that exits from the fourth plane.

2. The pulsed laser timing synthesis apparatus according to claim 1, characterized in that, The first birefringent crystal is a negative uniaxial birefringent crystal or a positive uniaxial birefringent crystal; The angle between the optical axis of the first birefringent crystal and the first plane is . The optical axis of the first birefringent crystal is parallel to the plane defined by the first sub-laser, the second sub-laser, and the third sub-laser, and the distance between the first plane and the second plane is [missing information]. The spacing between adjacent sub-lasers, D, should satisfy: in, The refractive index of the o-ray inside the first birefringent crystal is... Let be the e-ray refractive index inside the first birefringent crystal.

3. The pulsed laser timing synthesis apparatus according to claim 2, characterized in that, The second birefringent crystal is either a negative uniaxial birefringent crystal or a positive uniaxial birefringent crystal; The angle between the optical axis of the second birefringent crystal and the third plane is... The optical axis of the second birefringent crystal is parallel to the plane defined by the first, second, and third sub-lasers, and the distance between the third and fourth planes is... satisfy: in, The refractive index of the o-ray inside the second birefringent crystal. is the e-ray refractive index inside the second birefringent crystal.

4. The pulsed laser timing synthesis apparatus according to claim 1, characterized in that, The light source module includes a sub-laser emitting unit and a beam spacing and pointing control unit. The sub-laser emitting unit includes at least two sub-lasers for emitting lasers. The beam spacing and pointing control unit is used to adjust the lasers emitted by the sub-laser emitting unit to form a first sub-laser, a second sub-laser, and a third sub-laser.

5. The pulsed laser timing synthesis apparatus according to claim 4, characterized in that, The sub-laser emitting unit includes two sub-lasers that generate two laser beams. The beam spacing and pointing control unit includes a polarizing beam splitter to split the laser beam generated by one of the lasers, forming the first sub-laser and the third sub-laser.

6. The pulsed laser timing synthesis apparatus according to claim 4, characterized in that, The sub-laser emitting unit includes four sub-lasers that generate four linearly polarized laser beams. The beam spacing and pointing control unit includes a polarization beam combiner to combine the polarized laser beams generated by two of the lasers to form the second sub-laser.

7. The pulsed laser timing synthesis apparatus according to claim 1, characterized in that, Pulse widths of the first, second, and third sub-lasers and repetition frequency All are the same, the specific time delay It should meet the following requirements: .

8. The pulsed laser timing synthesis apparatus according to claim 4, characterized in that, The sub-laser includes one or more of pulse-emitting fiber lasers, solid-state lasers, semiconductor lasers, and gas lasers.

9. The pulsed laser timing synthesis apparatus according to claim 1, characterized in that, The first birefringent crystal and the second birefringent crystal are uniaxial crystals with a birefringence coefficient greater than 0.1; The first and second birefringent crystals comprise yttrium vanadate or Iceland spar.

10. The pulsed laser timing synthesis apparatus according to claim 1, characterized in that, The polarization modulator includes at least one of an electro-optic modulator, an acousto-optic modulator, and a magneto-optic modulator.

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