Speckle-free white light laser

Abstract

The present application relates to a kind of speckle-free white light laser, including pump source, first degenerate cavity, second degenerate cavity, first laser crystal and second laser crystal;Pump source is blue light semiconductor laser;First degenerate cavity includes laser input mirror, first imaging lens, beamsplitter and first wavefront modulator;Second degenerate cavity includes laser output mirror, beamsplitter, second imaging lens and second wavefront modulator;Pump source is injected into first degenerate cavity and second degenerate cavity respectively, and red light is generated in the first degenerate cavity by pumping first laser crystal, and green light is generated in the second degenerate cavity by pumping second laser crystal;Red light generated in the first degenerate cavity, green light generated in the second degenerate cavity and the part of blue light that pump source does not participate in frequency conversion jointly synthesize white light.The speckle-free white light laser of the present application controls the coherence and intensity ratio of red light and green light by wavefront modulator, can produce uniform white light laser, and is simple and convenient to operate.

Description

Technical Field

[0001] This invention relates to the fields of laser holography, lighting, and laser display, and particularly to a speckle-free white laser. Background Technology

[0002] Lasers are widely used in laser processing (cutting, welding, manufacturing, 3D printing, marking), information technology (laser anti-counterfeiting, holographic information storage, laser color display, laser TV, laser projectors), sensing and detection, and communication (fiber optic communication, free-space optical communication, visible light communication). White lasers, as a new product, will have unique industrial applications. In laser holography, if colored or white lasers can be used to generate holographic interference fringes, in principle, not only the outline information of an object can be reflected, but also its color information. This is a technology for truly recording and reproducing all-around information about an object. This technology not only greatly increases the amount of information contained in the hologram, improves the reliability of laser anti-counterfeiting, and increases the difficulty of information decryption, but also realistically reproduces the three-dimensional and color information of the object.

[0003] Lighting and display light sources on the market mainly fall into three categories: thermal radiation light sources, gas discharge light sources, and semiconductor light sources. Incandescent lamps, metal halide lamps, and LEDs, for example, play an important role in daily production and life. However, these light sources all suffer from problems such as low luminous efficiency, poor directionality, and difficulty in heat dissipation. Another type of light source is laser, which possesses high coherence, high directionality, and monochromaticity. However, because of the high coherence and monochromaticity of lasers, diffraction effects and spectral deficiencies often occur, resulting in numerous speckle patterns, and it is rarely used for lighting and displays.

[0004] To address the aforementioned issues, the solution provided by this invention reduces laser coherence, weakens diffraction effects, and improves beam uniformity, achieving a speckle-free light source effect. Compared to incandescent and metal halide lamps, this invention offers higher energy conversion efficiency and a simpler, more efficient heat dissipation device, saving energy and extending the light source's lifespan. Compared to LED light sources, this invention provides better directionality, a longer illumination distance, and higher uniformity. It also simplifies lamp design and reduces costs. This invention allows for control of the spectral ratio by loading holographic images, resulting in better output effects and simple operation. This invention can be widely applied in laser holography, information recording, interferometry, military applications, and various scenarios requiring long-distance illumination, such as automotive and aerospace applications.

[0005] Patent document CN107994448A discloses a white laser that controls the power ratio of red and green light by adjusting the pump light power incident on two resonant cavities through two adjustable attenuators. However, this laser is a coherent light source and cannot control the coherence and smoothness of the output beam. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this invention proposes a speckle-free white laser that is simple to operate, has adjustable coherence, and adjustable spectral ratio. By coupling two degenerate cavities, three wavelengths of laser light are output from the same laser output mirror. The output beam intensity, coherence, and smoothness can be controlled more precisely and with higher control efficiency through two independent wavefront modulators.

[0007] The technical solution adopted in this invention is as follows:

[0008] A speckle-free white laser includes a pump source, a first laser crystal, and a second laser crystal. It is characterized by further including a coupled first degenerate cavity and a second degenerate cavity. The first degenerate cavity includes a laser input mirror, a first imaging lens, a beam splitter, and a first wavefront modulator. The second degenerate cavity includes a laser output mirror, a beam splitter, a second imaging lens, and a second wavefront modulator. The first and second degenerate cavities are coupled through the beam splitter.

[0009] The pump source is injected into the first degenerate cavity and the second degenerate cavity respectively. The first laser crystal is pumped in the first degenerate cavity to generate red light, and the second laser crystal is pumped in the second degenerate cavity to generate green light. By controlling the first wavefront modulator and the second wavefront modulator, the first degenerate cavity and the second degenerate cavity generate red light and green light with different intensities, different coherence, and different near-field uniformity. These are mixed with the blue light from the pump source that does not participate in frequency conversion in different proportions to obtain white light of various wavelengths.

[0010] The pump source enters the first degenerate cavity through the optical isolator; the laser input mirror is placed perpendicular to the pump source; the beam splitter is placed at a 45-degree angle to the laser input mirror; the first imaging lens is located between the laser input mirror and the beam splitter, and the distance to both is the focal length of the first lens; the first laser crystal is located between the laser input mirror and the first imaging lens; the first wavefront modulator is placed at a 45-degree angle to the beam splitter, perpendicular to the laser input mirror, and the distance between the first wavefront modulator and the beam splitter is the focal length of the first imaging lens; the second wavefront modulator is located to the right of the beam splitter, at a 45-degree angle to the beam splitter, parallel to the laser input mirror, and the distance between the second wavefront modulator and the beam splitter is the focal length of the second imaging lens; the second imaging lens... The mirror is parallel to the first wavefront modulator, located between the beam splitter and the laser output mirror, and the distance to both is the focal length of the second imaging lens; the second laser crystal is located between the second imaging lens and the laser output mirror; the laser input mirror is perpendicular to the first wavefront modulator, parallel to the second wavefront modulator, and perpendicular to the laser output mirror; the pump source is injected into the first degenerate cavity and the second degenerate cavity respectively, pumping the first laser crystal in the first degenerate cavity to generate red light, and pumping the second laser crystal in the second degenerate cavity to generate green light; by controlling the first wavefront modulator and the second wavefront modulator, the first degenerate cavity and the second degenerate cavity can generate red light and green light with different intensities, different coherence, and different smoothness, which can be mixed with the blue light from the pump source that has not participated in frequency conversion in different proportions to obtain various white lights.

[0011] The first wavefront modulator can load holographic images with different radii of curvature, so that the reflected light is focused at the focal point of the first imaging lens to obtain degenerate cavities of different lengths, thereby controlling the longitudinal mode distribution within the cavity.

[0012] The first wavefront modulator can load different images and control the mode distribution and number of modes within the first degenerate cavity, thereby controlling the coherence of the output beam.

[0013] The first wavefront modulator can load different images and control the intracavity loss of the first degenerate cavity, thereby controlling the intensity of the output beam.

[0014] The first wavefront modulator can load different images and control the smoothness of the output beam by controlling the size of each pixel in the image, the distance between pixels, and the modulation amplitude and precision of the entire image.

[0015] The size, position, arrangement, grayscale value, and radius of curvature of each pixel in the hologram can be arbitrarily set according to actual needs.

[0016] The first wavefront modulator can effectively control the wavefront of visible light and has a reflectivity of over 90% for visible light.

[0017] The second wavefront modulator has the same function as the first wavefront modulator.

[0018] The first degenerate cavity and the second degenerate cavity are coupled together through the beam splitter.

[0019] The pump source is a blue light pump source.

[0020] The optical isolator allows pump light to pass through in the forward direction, preventing backward-propagating beams from entering the pump source.

[0021] The first laser crystal can generate red light when pumped by blue light.

[0022] The second laser crystal can generate green light when pumped by blue light.

[0023] The first heat sink is used to dissipate heat from the first laser crystal.

[0024] The second heat sink is used to dissipate heat from the second laser crystal.

[0025] The red light generated in the first degenerate cavity is transmitted through the beam splitter into the second degenerate cavity, and finally output from the laser output mirror.

[0026] The green light generated in the second degenerate cavity is output outside the cavity from the laser output mirror.

[0027] The blue light that is not oscillating when injected into the first degenerate cavity by the pump source enters the second degenerate cavity through the beam splitter and is finally output from the laser output mirror outside the cavity.

[0028] The pump source is blue light that enters the second degenerate cavity directly from the beam splitter, and the portion that does not oscillate is output from the laser output mirror outside the cavity.

[0029] The first wavefront modulator and the second wavefront modulator can be either amplitude-type wavefront modulators or phase-type wavefront modulators.

[0030] The first computer is used to design and generate holograms, and is connected to the first wavefront modulator, on which different modulation signals are loaded.

[0031] The second computer is used to design and generate holograms and is connected to the second wavefront modulator, on which different modulation signals are loaded.

[0032] The red light generated in the first degenerate cavity, the green light generated in the second degenerate cavity, and the blue light from the pump source that did not participate in frequency conversion are mixed in different intensity ratios to output different types of white light.

[0033] The laser input mirror has a transmittance of over 95% for blue light and a reflectance of over 99% for red light.

[0034] The laser output mirror has a transmittance of over 80% for blue and red light and a reflectance of over 97% for green light.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. This invention utilizes two laser crystals to generate two wavelengths of laser light under the action of the same pump source. By controlling the intensity ratio of red, green, and blue light, multiple colors of light can be obtained.

[0037] 2. The present invention introduces a degenerate cavity, which increases the number of modes of the output laser, reduces the spatial coherence of the output beam, weakens the diffraction effect caused by coherent beam illumination, and results in better display effect;

[0038] 3. This invention controls the spatial coherence of the output beam by loading an image onto the degenerate cavity to control the mode distribution, while improving the uniformity of the output beam. Different mode distributions also correspond to different loss coefficients of the degenerate cavity, which can adjust the intensity of the output beam.

[0039] 4. This invention uses a wavefront modulator to replace the reflector of a traditional degenerate cavity. By loading modulation images with different radii of curvature onto the wavefront modulator, the cavity length of the degenerate cavity can be easily adjusted, and the longitudinal mode distribution within the cavity can be controlled. Moreover, compared with a traditional degenerate cavity, there are fewer components, the cavity length is shorter under the same parameters, the structure is more compact, and space is saved.

[0040] 5. The modulated image used in this invention is designed and generated on a computer. The size, position, gray value of each pixel in the image, as well as the radius of curvature of the entire image, can be set and erased according to actual needs. The whole process is digital, simple and convenient to operate, low control cost, and high efficiency.

[0041] 6. This invention couples two degenerate cavities together to output three wavelengths of laser light from the same laser output mirror. The threshold, number of modes in the cavity, mode distribution and other parameters of the two degenerate cavities can be independently controlled by two wavefront modulators, which makes the control of the output beam intensity, coherence and smoothness more precise and the control efficiency higher.

[0042] 7. Compared with white light lasers (CN107994448A), the present invention provides speckle-free, low-coherence lasers. Not only can the intensity be controlled, but also the coherence and smoothness can be controlled, which has more application scenarios, especially in the fields of imaging and lighting. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of an embodiment of the speckle-free white laser of the present invention.

[0044] Figure 2 Phase of the embodiment of the present invention Figure 1 .

[0045] Figure 3 Phase of the embodiment of the present invention Figure 2 .

[0046] Figure 4 Phase of the embodiment of the present invention Figure 3 .

[0047] Figure 5 Phase of the embodiment of the present invention Figure 4 .

[0048] Figure 6 Phase of the embodiment of the present invention Figure 5 .

[0049] Figure 7 Phase of the embodiment of the present invention Figure 6 .

[0050] Figure 1 In the middle: 1-Pump source, 2-Optical isolator, 3-Laser input mirror, 4-First imaging lens, 5-Beam splitter, 6-First laser crystal, 7-First heat sink, 8-First wavefront modulator, 9-First computer, 10-Second heat sink, 11-Second laser crystal, 12-Second wavefront modulator, 13-Second imaging lens, 14-Laser output mirror, 15-Second computer. Detailed Implementation

[0051] 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, and 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.

[0052] Please see Figure 1 , Figure 1The figure shows a schematic diagram of an embodiment of the speckle-free white laser of the present invention. As shown, a speckle-free white laser includes a pump source 1, an optical isolator 2, a laser input mirror 3, a first imaging lens 4, a beam splitter 5, a first laser crystal 6, a first heat sink 7, a first wavefront modulator 8, a first computer 9, a second heat sink 10, a second laser crystal 11, a second wavefront modulator 12, a second imaging lens 13, a laser output mirror 14, and a second computer 15.

[0053] The first degenerate cavity includes a laser input mirror 3, a first imaging lens 4, a beam splitter 5, and a first wavefront modulator 8; the second degenerate cavity includes a second wavefront modulator 12, a beam splitter 5, a second imaging lens 13, and a laser output mirror 14; the pump source 1 enters the first degenerate cavity through the optical isolator 2; the laser input mirror 3 is placed perpendicular to the pump source 1; the beam splitter 5 is placed at a 45-degree angle to the laser input mirror 3; the first imaging lens 4 is located between the laser input mirror 3 and the beam splitter 5, and the distance to both is the focal length of the first lens 4; the first laser crystal 6 is located between the laser input mirror 3 and the first imaging lens 4; the first wavefront modulator 8 is placed at a 45-degree angle to the beam splitter 5 and perpendicular to the laser input mirror 3, the second wavefront modulator 12 includes a second wavefront modulator 12, a beam splitter 5, a second imaging lens 13, and a laser output mirror 14. The distance between the wavefront modulator 8 and the beam splitter 5 is the focal length of the first imaging lens 4; the second wavefront modulator 12 is placed to the right of the beam splitter 5 at a 45-degree angle to the beam splitter 5 and parallel to the laser input mirror 3, and the distance between the second wavefront modulator 12 and the beam splitter 5 is the focal length of the second imaging lens 13; the second imaging lens 13 is parallel to the first wavefront modulator 8, located between the beam splitter 5 and the laser output mirror 14, and the distance to both is the focal length of the second imaging lens 13; the second laser crystal 11 is located between the second imaging lens 13 and the laser output mirror 14; the laser input mirror 3 is perpendicular to the first wavefront modulator 8, parallel to the second wavefront modulator 12, and perpendicular to the laser output mirror 14;

[0054] The pump source 1 is injected into the first degenerate cavity and the second degenerate cavity respectively. The first laser crystal 6 is pumped in the first degenerate cavity to generate red light, and the second laser crystal 11 is pumped in the second degenerate cavity to generate green light. By controlling the first wavefront modulator 8 and the second wavefront modulator 12, the first degenerate cavity and the second degenerate cavity can generate red light and green light with different intensities, different coherence, and different smoothness. These can be mixed with the blue light from the pump source 1 that has not participated in frequency conversion in different proportions to obtain a variety of white light.

[0055] In the example:

[0056] The first wavefront modulator 8 can load images with different radii of curvature, so that the reflected light is focused at the focal point of the first imaging lens 4, forming an imaging system with the first imaging lens 4. By controlling the radius of curvature of the image, the cavity length of the first degenerate cavity can be adjusted, thereby controlling the longitudinal mode distribution in the cavity.

[0057] The first wavefront modulator 8 can load different images. By designing images with different distribution characteristics, it controls the mode distribution and number of modes within the first degenerate cavity, thereby controlling the coherence of the output beam. Compared to Figure 2 The image shown is a control image. Figure 3 The number of intracavity laser transverse modes corresponding to the controlled image shown will be greater, and the coherence of the output beam will be lower.

[0058] The first wavefront modulator 8 can load different images. By designing images of varying complexity, the intracavity loss of the first degenerate cavity can be controlled, thereby controlling the intensity of the output beam. Compared to Figure 2 The image shown is a control image. Figure 3 The cavity loss corresponding to the controlled image shown will be greater, and the intensity of the output beam will be reduced.

[0059] The first wavefront modulator 8 can load different images. By designing the size of each modulation unit in the loaded image, the distance between modulation units, and the modulation amplitude and precision of the entire image, the smoothness of the output beam can be controlled. For example, the size of each modulation unit can be set to 10 micrometers or 20 micrometers, the modulation amplitude of the entire image can be set to 0–2π or 0–4π, and the modulation precision can be set to divide 0–2π into 4 or 10 equal parts; compared to Figure 3 The image shown is a control image. Figure 4 The size of each modulation unit in the modulated image shown is Figure 3 One-quarter of the beam has more refined lateral modulation, which can control the smoothness of the output beam. Figure 4 It contains only two values: 0 and 2π. Figure 5 Dividing 0 to 2π into 16 equal parts, the fine division of the phase can also control the smoothness of the output beam; Figure 6 and Figure 7 With different focusing radii, the divergence angle of the beam inside the cavity can be controlled, as well as the beam waist radius and position of the output beam;

[0060] The first wavefront modulator 8 can effectively control the wavefront of visible light and has a reflectivity of over 90% for visible light.

[0061] The second wavefront modulator 12 has the same function as the first wavefront modulator 8;

[0062] The first degenerate cavity and the second degenerate cavity are coupled together through the beam splitter 5;

[0063] The pump source 1 is a blue semiconductor laser;

[0064] The optical isolator 2 allows the pump light to pass through in the forward direction, preventing the reverse-propagating beam from entering the pump source 1;

[0065] Both the first laser crystal 6 and the second laser crystal 11 are praseodymium-doped laser crystals.

[0066] The first heat sink 7 includes, but is not limited to, an air-cooled heat sink, a water-cooled heat sink, and a copper heat sink block, for dissipating heat from the first laser crystal 6.

[0067] The second heat sink 10 includes, but is not limited to, an air-cooled heat sink, a water-cooled heat sink, and a copper heat sink block, for dissipating heat from the second laser crystal 11.

[0068] The red light generated in the first degenerate cavity is transmitted through the beam splitter 5 into the second degenerate cavity, and finally outputs out of the cavity from the laser output mirror 14.

[0069] The green light generated in the second degenerate cavity is output from the laser output mirror 14 outside the cavity.

[0070] The blue light that is not oscillating when injected into the first degenerate cavity by the pump source 1 enters the second degenerate cavity through the beam splitter 5, and is finally output from the laser output mirror 14.

[0071] The blue light from the pump source 1 directly enters the second degenerate cavity from the beam splitter 5. Most of the blue light pumps the second laser crystal to produce green light, and a small portion of the blue light from the non-oscillating portion is output from the laser output mirror outside the cavity.

[0072] The first wavefront modulator 8 and the second wavefront modulator 12 can be amplitude-type wavefront modulators or phase-type wavefront modulators, including but not limited to spatial light modulators, digital micromirror arrays, and phase plates.

[0073] The first computer 9 is connected to the first wavefront modulator 8, and loads different modulation signals on the first wavefront modulator 8 to control the laser mode distribution in the first degenerate cavity.

[0074] The second computer 15 is connected to the second wavefront modulator 12, and loads different modulation signals onto the second wavefront modulator 12 to control the laser mode distribution in the second degenerate cavity.

[0075] The red light generated in the first degenerate cavity, the green light generated in the second degenerate cavity, and the blue light from the pump source that did not participate in frequency conversion are mixed in different intensity ratios to output different types of white light.

[0076] The laser input mirror 3 is a plane mirror coated with a dielectric film, which has a transmittance of more than 95% for blue light and a reflectance of more than 99% for red light. The blue light from the pump source 1 can enter the first degenerate cavity through it, and the first laser crystal 6 is pumped in the first degenerate cavity to generate red light, and the red light can oscillate in the first degenerate cavity.

[0077] The laser output mirror 14 is a plane mirror coated with a dielectric film, which has a transmittance of more than 80% for blue and red light and a reflectance of more than 97% for green light. The blue light from the pump source 1 enters the second degenerate cavity after passing through the laser input mirror 3 and the beam splitter 5. In the second degenerate cavity, the second laser crystal 11 is pumped to generate green light, and the green light can oscillate in the second degenerate cavity.

[0078] The beam splitter 5 is a plane mirror coated with a dielectric film, which has a reflectivity of 45% for blue light, over 98% for red light, and over 99% for green light.

[0079] Experiments show that the device described in this invention can effectively control the distribution of laser modes in two degenerate cavities by loading different modulation images onto two wavefront modulators, thereby controlling the intensity, coherence, and smoothness distribution of red and green light respectively. By mixing the red and green light generated by the two degenerate cavities with the blue light from the pump source that did not participate in frequency conversion in different proportions, different white light can be obtained. This invention features simple structure, high degree of digitization, low cost of parameter modification, and high control efficiency.

Claims

1. A speckle-free white light laser comprising a pump source, a first laser crystal and a second laser crystal, characterized in that, It also includes a coupled first degenerate cavity and a second degenerate cavity; the first degenerate cavity includes a laser input mirror, a first imaging lens, a beam splitter, and a first wavefront modulator, and the second degenerate cavity includes a laser output mirror, a beam splitter, a second imaging lens, and a second wavefront modulator; the first degenerate cavity and the second degenerate cavity are coupled through the beam splitter; The pump source is injected into the first degenerate cavity and the second degenerate cavity respectively. The first laser crystal is pumped in the first degenerate cavity to generate red light, and the second laser crystal is pumped in the second degenerate cavity to generate green light. By controlling the first wavefront modulator and the second wavefront modulator, the first degenerate cavity and the second degenerate cavity generate red light and green light with different intensities, different coherence, and different near-field uniformity. These are mixed with the blue light from the pump source that does not participate in frequency conversion in different proportions to obtain white light of various wavelengths. The first and second wavefront modulators are loaded with different holographic images to obtain degenerate cavities of different lengths. The mode distribution and number of modes within the cavity are controlled to control the coherence of the output beam; or the cavity loss is controlled to control the intensity of the output beam; or the size of each pixel in the image, the distance between pixels, and the modulation amplitude and precision of the entire image are controlled to control the smoothness of the output beam.

2. The speckle-free white laser according to claim 1, characterized in that, The size, position, arrangement, grayscale value, and radius of curvature of each pixel in the hologram can be arbitrarily set according to actual needs.

3. The speckle-free white laser according to claim 1, characterized in that, The pump source is a blue light pump source, and the laser input mirror is a plane mirror coated with a dielectric film. It has a transmittance of more than 95% for blue light and a reflectance of more than 99% for red light. The blue light enters the first degenerate cavity, pumps the first laser crystal in the first degenerate cavity to generate red light, and the red light oscillates in the first degenerate cavity. The laser output mirror is a plane mirror coated with a dielectric film, which has a transmittance of more than 80% for blue and red light and a reflectance of more than 97% for green light. The blue light from the pump source enters the second degenerate cavity after passing through the laser input mirror and the beam splitter. The second laser crystal is pumped in the second degenerate cavity to generate green light, and the green light oscillates in the second degenerate cavity. The beam splitter is a plane mirror coated with a dielectric film, which has a reflectivity of 45% for blue light, over 98% for red light, and over 99% for green light.

4. The speckle-free white laser according to claim 1, characterized in that, Both the first laser crystal and the second laser crystal are laser crystals doped with trivalent praseodymium ions.

5. The speckle-free white laser according to any one of claims 1-4, characterized in that, The laser input mirror (3) is placed perpendicular to the pump source (1), the beam splitter (5) is placed at a 45-degree angle to the laser input mirror (3), and the first imaging lens (4) is located between the laser input mirror (3) and the beam splitter (5), and the distance to both is the focal length of the first imaging lens (4). The first wavefront modulator (8) is provided on the red light reflection path of the beam splitter (5), and the first wavefront modulator (8) is placed at a 45-degree angle with the beam splitter (5) and perpendicular to the laser input mirror (3). The distance between the first wavefront modulator (8) and the beam splitter (5) is the focal length of the first imaging lens (4). A second wavefront modulator (12) is provided on the red light transmission path of the beam splitter (5). The second wavefront modulator (12) is placed at a 45-degree angle to the beam splitter (5) and parallel to the laser input mirror (3). The distance between the second wavefront modulator (12) and the beam splitter (5) is the focal length of the second imaging lens (13). A second imaging lens (13), a second laser crystal (11), and a laser output mirror (14) are provided on the green light reflection path of the beam splitter (5). The second imaging lens (13) is parallel to the first wavefront modulator (8). The distance from the second imaging lens (13) to the beam splitter (5) and the distance from the second imaging lens (13) to the laser output mirror (14) are both the focal length of the second imaging lens (13). The laser output mirror (14) is perpendicular to the laser input mirror (3).

6. The speckle-free white laser according to any one of claims 1-4, characterized in that, It also includes, The first computer (9) is connected to the first wavefront modulator (8) and is used to design and generate holograms and load different modulation signals onto the first wavefront modulator (8); The second computer (15), connected to the second wavefront modulator (12), is used to design and generate holograms and load different modulation signals onto the second wavefront modulator (12).

7. The speckle-free white laser according to any one of claims 1-4, characterized in that, It also includes, The first heat sink (7) is used to dissipate heat for the first laser crystal (6); The second heat sink (10) is used to dissipate heat for the second laser crystal (11).

8. The speckle-free white laser according to any one of claims 1-4, characterized in that, The first wavefront modulator (8) and the second wavefront modulator (12) can effectively control the wavefront of visible light and have a reflectivity of more than 90% for visible light.

9. The speckle-free white laser according to claim 8, characterized in that, The first wavefront modulator (8) and the second wavefront modulator (12) are amplitude-type wavefront modulators or phase-type wavefront modulators.

Images