A folded frequency-doubled laser system based on a double-pass periodically polarized crystal

Abstract

This application discloses a folded frequency-doubled laser system based on a double-pass periodically polarized crystal, including a laser source for generating high-power single-frequency fundamental light and a focusing lens for focusing the fundamental light output from the laser source onto the periodically polarized crystal. In the embodiments of this application, the above-mentioned folded frequency-doubled laser system based on a double-pass periodically polarized crystal is used. The frequency-doubled light after the first frequency doubling is reflected back to the periodically polarized crystal for a second frequency doubling by a plane mirror. The plano-convex lens can finely adjust the angle to adjust the phase difference between the fundamental light and the frequency-doubled light. According to the principle of optical path reversibility, the beam waist size and position in the second fold back into the periodically polarized crystal are strictly consistent with the focusing conditions of the first time, thereby ensuring the frequency doubling efficiency of the second time. At the same time, only one periodically polarized crystal is needed, resulting in lower cost and a more compact laser structure.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and more particularly to a folded frequency-doubled laser system based on a double-pass periodically polarized crystal. Background Technology

[0002] In recent decades, visible light laser sources (blue-green or red light) have found wide applications and demand in fields such as atomic and molecular spectroscopy, cold atom physics, quantum computing, optical data storage, laser television display imaging, and medical aesthetics. Among these, the most common and effective method for obtaining visible light sources is frequency doubling of lasers in the 0.8-2µm band. Depending on the phase-matching method, frequency doubling can be categorized into angle-matched, temperature-matched, and quasi-phase-matched (QPM) methods. Among these, frequency-doubling crystals using quasi-phase-matching exhibit superior characteristics such as high nonlinear coefficients (generally two orders of magnitude higher than angle- and temperature-matched crystals), zero walk-off angle, and wide transmittance. Based on these characteristics, researchers can develop long-lifetime, high-power, low-cost, and small-volume tunable compact solid-state visible laser sources.

[0003] Currently, commercially available periodically polarized crystals mainly include PPLN, PPKTP, and PPSLT, and a single pass through these crystals is usually sufficient to achieve high frequency doubling efficiency. However, in certain special cases, to pursue higher frequency doubling efficiency, it is often necessary to cascade multiple crystals for frequency doubling [G. Samanta, S. Kumar, K. Devi, and M. Ebrahim-Zadeh, Opt. Lett. 35, 3513 (2010)] or to use a single periodically polarized crystal optical path for multiple passes (including two or more). Among the multiple-pass schemes, the most efficient method is to use a resonant frequency doubling cavity [T. Meier, B. Willke, and K. Danzmann, Opt. Lett. 35, 3742 (2010)], with the highest reported frequency doubling efficiency reaching 90%.

[0004] However, these solutions would result in an excessively large laser structure, high cost, or more complex electronics, and reduced reliability. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a compact, highly efficient, and stable folded frequency-doubled laser system based on a double-pass periodically polarized crystal.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions.

[0007] This application provides a folded frequency-doubled laser system based on a double-pass periodically polarized crystal, comprising:

[0008] Laser light source, used to output high-power single-frequency fundamental frequency light;

[0009] A focusing lens is used to focus the fundamental frequency light output from the laser source onto a periodically polarized crystal;

[0010] The periodically polarized crystal is used to receive fundamental frequency light and output it as frequency-doubled light after frequency doubling.

[0011] A plane mirror is used to reflect the frequency-doubled light output from the periodically polarized crystal and the residual fundamental light back to the periodically polarized crystal for secondary frequency doubling;

[0012] A plano-convex lens, located between the periodically polarized crystal and the plane mirror, is used to reflect the fundamental frequency light and the second-order harmonic light reflected from the plane mirror back into the periodically polarized crystal along the original path under the same converging conditions.

[0013] A dichroic mirror, located between the focusing lens and the periodically polarized crystal, transmits the fundamental frequency light and reflects the frequency-doubled light, and is used to extract the frequency-doubled light output from the periodically polarized crystal.

[0014] The distance between the focusing lens and the center of the periodically polarized crystal is greater than the focal length of the focusing lens, and the angle of the plano-convex lens can be adjusted and is used to compensate for the phase difference introduced by the difference in refractive index of the fundamental frequency light and the second-order frequency light in air.

[0015] Further specifying, in the above-mentioned folded frequency-doubled laser system based on a double-pass periodically polarized crystal, the fundamental frequency light is a continuous or pulsed laser with a wavelength of 800-2000nm.

[0016] Further specifying, in the above-mentioned folded frequency-doubled laser system based on a double-pass periodically polarized crystal, the periodically polarized crystal is a PPLN crystal or PPSLT, PPKDP.

[0017] Further specifying, in the above-mentioned folded frequency-doubled laser system based on a double-pass periodically polarized crystal, the focal length of the plano-convex lens is greater than half the length of the periodically polarized crystal.

[0018] Further specifying, in the above-mentioned folded frequency-doubled laser system based on a double-pass periodically polarized crystal, the phase difference between the fundamental frequency light and the frequency-doubled light is π.

[0019] The present invention has at least the following beneficial effects:

[0020] 1. The frequency-doubled light after the first frequency doubling is reflected back to the periodically polarized crystal by a plane mirror for a second frequency doubling. The plano-convex lens can finely adjust the angle to adjust the phase difference between the fundamental frequency light and the frequency-doubled light. According to the principle of optical path reversibility, the size and position of the waist in the second fold back into the periodically polarized crystal are strictly consistent with the focusing conditions of the first time, thus ensuring the frequency doubling efficiency of the second time and making the adjustment of the optical path easier.

[0021] 2. Compared to the frequency multiplication in a single pass, this scheme improves frequency multiplication efficiency by more than 2 times;

[0022] 3. Compared with the frequency doubling method of cascading two or more crystals, this scheme only requires one periodic polarization crystal, which is lower in cost and allows the laser structure to be more compact, with a volume that is close to that of a single crystal in a single pass, thus ensuring high frequency doubling efficiency while miniaturizing.

[0023] 4. Compared to the scheme of passing the crystal through the resonant cavity multiple times, this scheme does not require additional servo control and a complex resonant cavity, resulting in lower electronic and optical costs and better stability.

[0024] 5. Compared with conventional double-pass optical paths, this scheme does not require an additional phase plate, reducing the loss caused by the phase compensation plate. It also does not require a plano-concave mirror. These functions can be achieved with just a plano-convex lens. Moreover, there are no strict restrictions on the focal length of the plano-convex lens. Its position only needs to be adjusted to collimate the output of the fundamental frequency light and the frequency-doubled light, which greatly reduces the overall design complexity of the laser system. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the folded frequency-doubled laser system based on a double-pass periodically polarized crystal, according to an embodiment of this application.

[0026] Figure 2 This is a schematic diagram of the power-efficiency relationship of the "Frequency Doubled Light 510" folded frequency doubled laser system based on a double-pass periodically polarized crystal, according to an embodiment of this application.

[0027] Figure Labels

[0028] Laser source-100, fundamental frequency light-110, optical isolator-200, focusing lens-300, dichroic mirror-400, periodically polarized crystal-500, frequency doubling light-510, plano-convex lens-600, plane mirror-700, high reflection mirror-800, shaping lens group-900. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0030] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0031] The following description, in conjunction with the accompanying drawings, details the folded frequency-doubled laser system based on a double-pass periodically polarized crystal provided in this application, through specific embodiments and application scenarios.

[0032] like Figure 1 As shown, this application embodiment provides a folded frequency-doubled laser system based on a double-pass periodically polarized crystal, including a laser source 100 for generating high-power single-frequency continuous fundamental light 110. An optical isolator 200 is provided on the optical path of the laser source 100 emitting the fundamental light 110. The optical isolator 200 transmits the fundamental light 110 incident from the laser source 100. A periodically polarized crystal 500 is provided on the optical path of the fundamental light 110 transmitted from the optical isolator 200 to generate frequency-doubled light 510 after frequency doubling the fundamental light 110. A plane mirror 700 is provided on the optical path of the frequency-doubled light 510 emitted from the periodically polarized crystal 500. The plane mirror 700 is used to reflect the frequency-doubled light 510 and the residual fundamental light 110 back to the periodically polarized crystal 500 for secondary frequency doubling.

[0033] A focusing lens 300 is provided between the optical isolator 200 and the periodic polarized crystal 500 to converge the fundamental frequency light 110 transmitted from the optical isolator 200 to the periodic polarized crystal 500. A plano-convex lens 600 with adjustable angle is provided between the periodic polarized crystal 500 and the plane mirror 700. The plano-convex lens 600 is used to adjust and compensate for the phase difference introduced by the difference in refractive index between the fundamental frequency light 110 and the frequency-doubled light 510 in air. At the same time, the plano-convex lens 600 is also used to refract the fundamental frequency light 110 and the frequency-doubled light 510 reflected from the plane mirror 700 back to the periodic polarized crystal 500 a second time along the original path under the same converging conditions.

[0034] A dichroic mirror 400 is provided between the focusing lens 300 and the periodically polarized crystal 500. The dichroic mirror 400 transmits the fundamental frequency light 110 and reflects the frequency-doubled light 510. The frequency-doubled light 510 emitted from the periodically polarized crystal 500 is reflected by the dichroic mirror 400 at a certain angle and is led out. The residual fundamental frequency light 110 reflected from the plane mirror 700 is transmitted through the dichroic mirror 400 and the focusing lens 300 and then shot to the optical isolator 200. At this time, the optical isolator 200 is used to prevent the fundamental frequency light 110 from returning to the laser source 100 along the original path and to lead the residual fundamental frequency light 110 to the optical aperture.

[0035] The laser source 100 generates a high-power single-frequency continuous fundamental frequency light 110. The fundamental frequency light 110 is output through an optical isolator 200. The overall isolation of the optical isolator 200 is generally greater than 25dB. It can be understood that the fundamental frequency light 110 can be a continuous or pulsed laser, and its wavelength can include any wavelength between 800 nm of the high-reflection mirror and 2000 nm of the optical isolator. The laser source 100 can be a fiber laser, a Ti:sapphire laser, or other laser source. In the actual optical path, different numbers of isolators can be cascaded according to the required isolation level.

[0036] Dichroic mirror 400 has high transmittance for fundamental frequency light 110 and high reflectivity for second-order light 510. Fundamental frequency light 110 is converged by focusing lens 300. The focal length of focusing lens 300 needs to be selected according to the different lengths of periodically polarized crystal 500 and the diameter of incident fundamental frequency light 110, so that the focusing condition of incident light on periodically polarized crystal 500 satisfies the Bold-Kleimann (BK) focusing condition (simply put, there is an optimal beam waist radius inside the crystal for a specific crystal length; for a more detailed calculation process, please refer to [BOYDG D, KLEINMAN D A. Parametric interaction of focused gaussian light beams[J]. Applied Physics,1968,39(8):3597-3639.]). Considering the refractive index of the crystal, the distance between focusing lens 300 and the center of periodically polarized crystal 500 needs to be greater than the focal length of the lens according to the length of periodically polarized crystal 500, so as to ensure that the first beam waist is located at the center of periodically polarized crystal 500.

[0037] After the fundamental frequency light 110 passes through the periodically polarized crystal 500 for the first time, the power of the frequency-doubled light 510 can be expressed as P. b,1 =A1 2Where A1 is the electric field amplitude of the frequency-doubled light 510 after the first pass through the periodically polarized crystal 500. The generated frequency-doubled light 510 and the residual fundamental light 110, after collimation by the plano-convex lens 600 and reflection by the plane mirror 700, are converged a second time into the periodically polarized crystal 500. According to the principle of optical path reversibility, the plano-convex lens 600 ensures that the waist of the second beam converged into the periodically polarized crystal 500 also satisfies the BK focusing condition and is located at the center of the periodically polarized crystal 500. After folding twice along the original path, the electric field amplitude of the frequency-doubled light 510 passing through the periodically polarized crystal 500 can be expressed as: Where A2 is the electric field amplitude of the frequency-doubled light 510 after the second pass through the periodically polarized crystal 500. Let be the phase difference between the fundamental frequency light 110 and the frequency-doubled light 510. Since the refractive indices of the two lights differ very little, the phase difference can be made equal to π simply by finely adjusting the angle of the plano-convex lens 600. At this point, the power of the frequency-doubled light 510 after passing through the periodically polarized crystal 500 twice can be expressed as: A2 2 With A1 2 They can be approximated as equal. Therefore, the frequency doubling efficiency after folding twice within the periodically polarized crystal 500 is approximately estimated to be more than twice the frequency doubling efficiency of a single pass through the periodically polarized crystal 500.

[0038] After the fundamental frequency light 110 and the frequency-doubled light 510 are split by the dichroic mirror 400, the fundamental frequency light 110 is guided into the light receiving plate through the side of the optical isolator 200, and the frequency-doubled light 510 is reflected out by the dichroic mirror 400.

[0039] It is understandable that the periodically polarized crystal 500 is a PPLN crystal, but it can also be any quasi-phase-matched crystal, such as PPKTP and PPSLT, or a non-periodic polarized crystal that meets the temperature matching conditions, such as LBO.

[0040] Understandably, the plano-convex lens 600 does not strictly limit the focal length; it only needs to be greater than half the length of the periodically polarized crystal 500 to collimate the first frequency-doubled light 510 and the fundamental light 110. At the same time, it has high transmission for light in both wavelength bands. The plano-convex lens 600 and the plane mirror 700 work together to reflect the frequency-doubled light 510 and the fundamental light 110 back along their original paths and refocus them into the periodically polarized crystal 500. The size and position of the beam waist are strictly consistent with the first time.

[0041] In this embodiment, a folded frequency-doubling laser system based on a double-pass periodically polarized crystal is used. The frequency-doubled light 510 after the first frequency doubling is reflected back to the periodically polarized crystal 500 for a second frequency doubling via a plane mirror 700. The plano-convex lens 600 can be finely adjusted to regulate the phase difference between the fundamental frequency light 110 and the frequency-doubled light 510. According to the principle of optical path reversibility, the beam waist size and position within the periodically polarized crystal 500 after the second folding are strictly consistent with the focusing conditions of the first fold, thus ensuring the efficiency of the second frequency doubling and making the adjustment of the optical path easier. Moreover, unlike plano-concave mirrors which have strict limitations on their radius of curvature and position, this solution does not have strict limitations on the focal length of the plano-convex lens 600. The position only needs to be adjusted so that the fundamental frequency light 110 and the frequency-doubled light 510 are collimated, which greatly reduces the overall design complexity of the laser system.

[0042] Compared to frequency multiplication in a single pass, this scheme improves frequency multiplication efficiency by more than 2 times.

[0043] Compared to cascading two or more crystals for frequency doubling, this scheme only requires one periodic polarization crystal 500, resulting in lower costs. Moreover, the laser structure can be more compact, with a volume that is almost the same as that of a single crystal passing through once, achieving high frequency doubling efficiency while ensuring miniaturization.

[0044] Compared to the scheme that involves multiple passes of the crystal within the resonant cavity, this scheme eliminates the need for redundant servo control and complex resonant cavities, resulting in lower electronic and optical costs and better stability.

[0045] Compared to conventional double-pass optical paths, this scheme does not require an additional phase plate, reducing the loss caused by the phase compensation plate, and also does not require a plano-concave mirror. All these functions can be achieved with just a single plano-convex lens 600.

[0046] In summary, the embodiments of this application take into account the compact structure of a single-pass frequency doubling crystal, while also having more than twice the frequency doubling efficiency and more flexible beam shaping capabilities compared to the single-pass method. Compared to the multiple-pass frequency doubling in the resonant cavity, the structure is more compact, the electronics are simpler and more reliable, and the light output is more stable. Compared to the traditional double-pass scheme, it does not require a phase plate or plano-concave mirror, and the structure is simpler.

[0047] In a preferred embodiment, the system further includes a high-reflection mirror 800 and a shaping lens group 900. The high-reflection mirror 800 is located on the reflection path of the frequency-doubled light 510 from the dichroic mirror 400 and is used to perform secondary reflection and extraction of the frequency-doubled light 510 reflected from the dichroic mirror 400. The shaping lens group 900 is located on the reflection path of the frequency-doubled light 510 from the high-reflection mirror 800 and is used to shape, expand, or shrink the frequency-doubled light 510.

[0048] The incident angle of the fundamental frequency light 110 and the frequency-doubled light 510 on the dichroic mirror 400 is 45°, that is, the angle between the frequency-doubled light 510 incident on the dichroic mirror 400 and the frequency-doubled light 510 reflected from the dichroic mirror 400 is 90°. The incident angle of the frequency-doubled light 510 reflected by the dichroic mirror 400 to the high-reflection mirror 800 is 45°. Similarly, the angle between the frequency-doubled light 510 incident on the high-reflection mirror 800 and the frequency-doubled light 510 reflected from the high-reflection mirror 800 is 90°.

[0049] It is understandable that the angles of the dichroic mirror 400 and the high-reflection mirror 800 are not limited to the one mentioned above. As long as the reflected frequency-doubled light 510 does not interfere, the above arrangement is to improve the overall compactness of the laser system and reduce its overall size.

[0050] Of course, the high-reflection mirror 800 can be removed, and the shaping lens group 900 can be placed on the reflected light path of the frequency doubling light 510 from the dichroic mirror 400. The same effect can be achieved in this case, but the overall size of the laser system will increase.

[0051] In this embodiment, a folded frequency-doubled laser system based on a double-pass periodically polarized crystal is used. The frequency-doubled light 510 is reflected and exported by a high-reflection mirror 800. Since the astigmatism of the exported frequency-doubled light 510 often needs to be shaped and its collimation needs to be readjusted, a shaping lens group 900 is set to shape, expand or shrink the frequency-doubled light 510.

[0052] In a preferred embodiment, to generate a high-power 9W continuous 780nm laser, the laser source 100 is an erbium-doped fiber laser, which generates a maximum of 15W continuous single-frequency 1560nm fundamental frequency light 110. The fundamental frequency light 110 is output after passing through a 1560nm optical isolator 200 (isolation degree of 35dB). The focusing lens 300 has high transmittance for the 1560nm fundamental frequency light 110 while having high reflectivity for the 780nm frequency-doubled light 510. The incident angle is 45°, and the incident spot diameter of the fundamental frequency light 110 is... The fundamental frequency light 110 is 1.0 mm long and is focused by a focusing lens 300 with a focal length of 50 mm. The periodic polarization crystal 500 is a PPLN crystal with a length of 60 mm, so that the beam waist radius incident on the periodic polarization crystal 500 is about 55 μm, which satisfies the Bold-Kleimann (BK) optimal focusing condition. Considering the refractive index of the crystal, the distance between the focusing lens 300 and the center of the periodic polarization crystal 500 is about 65 mm, ensuring that the first beam waist is located at the center of the periodic polarization crystal 500.

[0053] After the fundamental frequency light 110 passes through the periodically polarized crystal 500 for the first time, the output power and frequency doubling efficiency of the 780nm frequency-doubled light 510 output by the periodically polarized crystal 500 are measured as follows: Figure 2 As shown (P780nm-SP and Efficiency-SP), the plano-convex lens 600 has a focal length of 40mm and is used to collimate the fundamental frequency light 110 and the frequency-doubled light 510. At the same time, the phase difference between the 1560nm fundamental frequency light 110 and the 780nm frequency-doubled light 510 is adjusted by slightly rotating the angle of the plano-convex lens 600. Theoretically, the folding frequency doubling efficiency is optimal when the phase difference is π. In practice, the angle is optimized according to the output power of the folded 780nm frequency-doubled light 510. The plane mirror 700 reflects both the fundamental frequency light 110 and the frequency-doubled light 510 highly, and the incident angle is 0°.

[0054] After reflection by plane mirror 700, the second beam waist is located at the center of the frequency-doubled beam 510. According to the principle of optical path reversibility, the second beam waist remains approximately 55µm. After two frequency-doubled passes through the periodically polarized crystal 500, the power and efficiency of the frequency-doubled beam 510 are as follows: Figure 2 As shown in P780nm-DP and Efficiency-DP, it can be seen that after the periodically polarized crystal 500 is folded twice, the highest frequency doubling efficiency of the periodically polarized crystal 500 increases from 27% for single pass to 62%. The frequency doubling efficiency for double pass is more than twice that for single pass. After the folded and frequency-doubled 1560nm fundamental frequency light 110 and 780nm frequency-doubled light 510 are split by the dichroic mirror 400, the 1560nm fundamental frequency light 110 is received into the light block through the side light guide hole of the 1560nm optical isolator 200, and the 780nm frequency-doubled light 510 is led out through a high-reflection mirror 800. The led-out frequency-doubled light 510 is expanded by the shaping lens group 900 into a collimated laser output with a spot diameter of about 1.5mm.

[0055] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0056] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A folded frequency-doubled laser system based on a two-pass periodically poled crystal, characterized in that, The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device.

2. The folded frequency-doubled laser system based on a two-pass periodically poled crystal according to claim 1, wherein, The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device.

3. The folded frequency-doubled laser system based on a two-pass periodically poled crystal according to claim 1, wherein, The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device.

4. The folded frequency-doubled laser system based on a two-pass periodically poled crystal according to claim 1, wherein, The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling device and a method for generating a laser frequency doubling device. The application relates to a laser frequency doubling

Images