Dual-pass femtosecond laser compressor
By designing a two-pass femtosecond laser compressor, the number of times the beam passes through the grating is increased, solving the problem of compressors being limited by grating size in chirped pulse amplifiers, and achieving femtosecond laser output with greater beam extension and higher energy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUZHOU BELLIN LASER CO LTD
- Filing Date
- 2025-07-28
- Publication Date
- 2026-07-31
AI Technical Summary
In the prior art, the compressor design of the chirped pulse amplifier is limited by the size of the transmission grating, which cannot accommodate the large-energy chirped pulse broadening, resulting in limited output energy of the femtosecond laser.
A dual-pass femtosecond laser compressor is used. By re-injecting the light output from the compressor after the first pass into the compressor, the number of times the beam passes through the grating is increased. By using a combination design of transmission grating and mirror group, multiple compression of the beam is achieved, expanding the compression amount and adapting to chirped pulse amplifiers with a larger span.
With the grating spacing unchanged, the output single-pulse energy of the femtosecond laser was significantly improved, the design limitations of the chirped pulse amplifier were reduced, and greater compression and higher compression efficiency were achieved.
Smart Images
Figure CN224582682U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a two-way femtosecond laser compressor. Background Technology
[0002] After a femtosecond laser is generated, it typically needs to be connected to a laser amplifier to amplify its power and energy. Because the peak power of the amplified femtosecond laser pulse is high, it can easily damage the amplification devices. Currently, the mainstream method to avoid laser amplification damage is to use chirped pulse amplification technology. This involves first broadening the femtosecond laser into a picosecond or nanosecond laser, then amplifying it, and finally compressing the picosecond or nanosecond laser back into a femtosecond laser. Therefore, in high-energy laser amplification systems, the design of the compressor is crucial.
[0003] The compressor section of chirped pulse amplification technology typically uses a transmission grating as the dispersion compensation element. Its advantages are high efficiency and compatibility with larger energies. However, its disadvantage is that the larger the amount of dispersion to be compensated, the larger the size of the grating needs to be. Currently, the maximum length of a mature transmission grating is about 150mm, which limits the broadening of the chirped pulse amplifier and the final output energy. Utility Model Content
[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a two-way femtosecond laser compressor, which aims to solve the problem that the compression amount of the compressor in the chirped pulse amplifier is limited by the grating size.
[0005] The objective of this utility model is achieved through the following technical solution:
[0006] A two-way femtosecond laser compressor is characterized by including a transmission grating, a mirror assembly, mirrors, a beam-lowering mirror, and an output mirror.
[0007] In the first incident light path, the incident chirped pulse is connected to region one of the transmission grating, region one of the transmission grating is connected to the mirror group, the mirror group is connected to region two of the transmission grating, and region two of the transmission grating is connected to the mirror.
[0008] In the first reflected light path, the reflector is connected to region two of the transmission grating, region two of the transmission grating is connected to the reflector group, the reflector group is connected to region one of the transmission grating, and region one of the transmission grating is connected to the beam lowering reflector.
[0009] In the second incident light path, the beam lowering mirror connects to region three of the transmission grating, region three of the transmission grating connects to the mirror group, the mirror group connects to region four of the transmission grating, and region four of the transmission grating connects to the mirror.
[0010] In the second reflection optical path, the reflector is connected to region four of the transmission grating, region four of the transmission grating is connected to the reflector group, the reflector group is connected to region three of the transmission grating, region three of the transmission grating is connected to the output reflector, and the output reflector is followed by the compressed output pulse.
[0011] Furthermore, in the aforementioned two-way femtosecond laser compressor, the incident chirped pulse is a chirped pulse with a center wavelength of 1030nm, 1064nm, or 1342nm, an output power of 0–1000W, and a pulse width of 100fs–100ns.
[0012] Furthermore, in the aforementioned two-way femtosecond laser compressor, the transmission grating is a transmission grating with a working wavelength in the 1030nm, 1064nm, and 1342nm bands and a grating line density of 1 / mm to 10000 / mm.
[0013] Furthermore, in the aforementioned dual-path femtosecond laser compressor, the reflector group consists of two orthogonally arranged broadband reflectors, and the operating wavelength is the output wavelength of the infrared laser.
[0014] Furthermore, in the aforementioned two-way femtosecond laser compressor, the center-to-center distance between the two mirrors of the mirror assembly is 1mm to 200mm, and the distance between the mirror assembly and the transmission grating is 0 to 2000mm.
[0015] Furthermore, in the aforementioned two-way femtosecond laser compressor, the reflector is a broadband reflector, and the operating wavelength is the output wavelength of the infrared laser.
[0016] Furthermore, in the aforementioned dual-path femtosecond laser compressor, the beam lowering mirror (5) consists of two orthogonally arranged mirrors, which can increase or decrease the beam height by 0mm to 200mm.
[0017] Furthermore, in the above-mentioned dual-path femtosecond laser compressor, the center-to-center distance between the two lenses of the beam-lowering mirror (5) is 1mm to 200mm, and the distance between the beam-lowering mirror (5) and the transmission grating (2) is 0 to 200mm.
[0018] Compared with the prior art, this utility model has significant advantages and beneficial effects, specifically reflected in the following aspects:
[0019] This invention extends the number of times the compression grating can be used by re-injecting the light that was first output through the compressor into the compressor. This results in a greater compression amount without changing the grating spacing of the compressor, thus allowing for greater broadening of the chirped pulse amplifier, reducing the design limitations of the chirped pulse amplifier, and improving the single-pulse energy output of the femtosecond laser.
[0020] Increasing the number of times the beam passes through the grating doubles the dispersion of the compressor with the same grating aperture and grating spacing, thus accommodating chirped pulse amplifiers with greater spread or wider bandwidth.
[0021] Other features and advantages of this invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing specific embodiments of the invention. The objects and other advantages of this invention can be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description
[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 : A schematic diagram of the structure of the dual-pass femtosecond laser compressor of this utility model;
[0024] Figure 2 : Schematic diagram of the side view partition of the transmission grating. Detailed Implementation
[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0026] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this utility model, directional and ordinal terms are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0027] Because the pulse broadening and compression need to be matched in chirped pulse amplification, the beam of a traditional single-grating compressor passes through the grating four times. When the grating spacing is fixed, the amount of compression dispersion provided is fixed. This invention increases the number of times the beam passes through the grating, thereby doubling the dispersion of the compressor with the same grating aperture and grating spacing, thus adapting to chirped pulse amplifiers with larger broadening or larger bandwidth.
[0028] like Figure 1 , Figure 2 As shown, the two-way femtosecond laser compressor includes a transmission grating 2, a mirror group 3, a mirror 4, a beam-lowering mirror 5, and an output mirror 6.
[0029] The transmission grating 2 includes region 1 21, region 22, region 3 23 and region 4 24. Region 1 21 is the position where the incident chirped pulse first enters the transmission grating. Region 2 22 is another position on the grating at the same horizontal height as region 1 21. The distance between region 2 22 and region 1 200 mm is 1 to 200 mm. Region 3 23 is another position on the grating at the same vertical height as region 1 21. The distance between region 3 23 and region 1 200 mm is 1 to 200 mm. Region 4 24 is a position on the grating at the same vertical height as region 2 22 and the same horizontal height as region 3 23.
[0030] In the first incident light path, the incident chirped pulse 1 is connected to region 21 of the transmission grating 2, region 21 of the transmission grating 2 is connected to the mirror group 3, the mirror group 3 is connected to region 22 of the transmission grating 2, and region 22 of the transmission grating 2 is connected to the mirror 4.
[0031] In the first reflected light path, reflector 4 is connected to region 22 of transmission grating 2, region 22 of transmission grating 2 is connected to reflector group 3, reflector group 3 is connected to region 21 of transmission grating 2, and region 21 of transmission grating 2 is connected to beam lowering reflector 5.
[0032] In the second incident light path, the beam lowering reflector 5 is connected to region 23 of the transmission grating 2, region 23 of the transmission grating 2 is connected to the reflector group 3, the reflector group 3 is connected to region 24 of the transmission grating 2, and region 24 of the transmission grating 2 is connected to the reflector 4.
[0033] In the second reflection optical path, reflector 4 is connected to region 24 of transmission grating 2, region 24 of transmission grating 2 is connected to reflector group 3, reflector group 3 is connected to region 23 of transmission grating 2, region 23 of transmission grating 2 is connected to output reflector 6, and compressed output pulse 7 is after output reflector 6.
[0034] Among them, the incident chirped pulse 1 is a chirped pulse with a center wavelength of 1030nm, 1064nm, and 1342nm, an output power of 0-1000W, and a pulse width of 100fs-100ns. The incident chirped pulse is generated by passing a femtosecond seed source through an optical fiber stretcher.
[0035] Transmission grating 2 is a transmission grating with a working wavelength in the 1030nm, 1064nm, and 1342nm bands and a grating line density of 1 / mm to 10000 / mm.
[0036] The reflector group 3 consists of two orthogonally arranged broadband reflectors, with the operating wavelength being the output wavelength of the infrared laser. The center-to-center distance between the two mirrors in the reflector group 3 is 1mm to 200mm, and the distance between the reflector group 3 and the transmission grating 2 is 0 to 2000mm.
[0037] Reflector 4 is a broadband reflector, and its operating wavelength is the output wavelength of the infrared laser.
[0038] The beam-lowering reflector 5 consists of two orthogonally arranged reflectors, which can increase or decrease the beam height by 0mm to 200mm. The center-to-center distance between the two mirrors of the beam-lowering reflector 5 is 1mm to 200mm, and the distance between the beam-lowering reflector 5 and the transmission grating 2 is 0mm to 200mm. The beam-lowering reflector 5 can be replaced with a mirror if the output effect allows.
[0039] During two-way femtosecond laser compression, in the first incident optical path, the incident chirped pulse 1 is incident as parallel light. After passing through region 21 of the transmission grating 2, the light of different frequency components has different diffraction angles in space, causing the beam to diverge macroscopically perpendicular to the grating lines. Then, the diverging light is reflected parallel to region 22 of the transmission grating 2 by the mirror group 3. After passing through region 22 of the transmission grating 2, the diverging light is incident parallel to the mirror 4. The mirror 4 reflects the beam slightly deviating from the incident light. After passing through region 22 of the transmission grating 2, the beam contracts macroscopically perpendicular to the grating lines due to diffraction. The mirror group 3 reflects the contracted light parallel back to region 21 of the transmission grating 2. The contracted beam after passing through region 21 of the transmission grating 2 becomes parallel light and completes one compression.
[0040] The compressed output light is incident on the beam lowering mirror 5. The beam lowering mirror 5 lowers the beam height and reflects the lowered beam to region 23 of the transmission grating 2 at an angle parallel to the compressed output light, for a second compression. After passing through region 23 of the transmission grating 2, the light of different frequency components diffracts at different angles in space, causing the beam to diverge macroscopically perpendicular to the grating lines. Then, the diverging light is reflected parallel to region 24 of the transmission grating 2 by the mirror group 3. After passing through region 24 of the transmission grating 2, the diverging light is incident parallel to the mirror 4. The mirror 4 reflects the beam slightly deviating from the incident light. After passing through region 24 of the transmission grating 2, the beam contracts macroscopically perpendicular to the grating lines due to diffraction. The mirror group 3 reflects the contracted light parallel back to region 23 of the transmission grating 2. The contracted beam after passing through region 23 of the transmission grating 2 becomes parallel light and completes the second compression.
[0041] The second compressed output beam is located directly below the incident chirped pulse 1 beam, and the two beams are in opposite directions. It is reflected by the output reflector 6 and becomes the compressed output pulse 7.
[0042] Example
[0043] The incident chirped pulse 1 has a center wavelength of 1030 nm and a spectral width of 1.8 nm@3 dB and 6 nm@10 dB. Before amplification, the 196 fs pulse is broadened to 1 ns using a stretcher. The transmission grating 2 has dimensions of 100 mm × 30 mm × 6.35 mm and a grating line density of 1739 / mm². The beam-lowering mirror 5 has a center-to-center distance of 15 mm between its two mirrors and is 200 mm away from the transmission grating. The mirror group 3 has a center-to-center distance of 20 mm between its two mirrors and is 266 mm away from the transmission grating. The incident chirped pulse 1 is parallel light. After passing through the transmission grating 2, the light of different frequency components diffracts at different angles in space, causing the beam to diverge macroscopically perpendicular to the grating lines. Then, the diverging light is reflected parallel to other positions on the transmission grating 2 by the mirror group 3. The diverging light, after passing through the transmission grating 2, is then incident parallel to the mirror 4. The mirror 4 reflects the beam slightly off-center from the incident light. After passing through the transmission grating 2, the beam contracts macroscopically perpendicular to the grating lines due to diffraction. The mirror group 3 reflects the contracted light parallel back to the transmission grating 2. The contracted beam after passing through the transmission grating 2 becomes parallel light and completes one compression. The compressed light then enters the beam lowering mirror 5. The beam lowering mirror 5 lowers the beam height and reflects the lowered beam back to the transmission grating 2 at an angle parallel to the output light of the first compression. The second compression begins. After the beam passes through the transmission grating 2, the different frequency components of the light diffract at different angles in space, causing the beam to diverge macroscopically perpendicular to the grating lines. Then, the diverging light is reflected parallel to the transmission grating 2 by the mirror group 3. After passing through the transmission grating 2, the diverging light is incident parallel to the mirror 4. The mirror 4 reflects the beam slightly off-center from the incident light. After passing through the transmission grating 2, the beam will contract macroscopically perpendicular to the grating lines due to diffraction. The mirror group 3 reflects the contracted light parallel back to the transmission grating 2. The contracted beam after passing through the transmission grating 2 becomes parallel light and completes the second compression. The beam output by the second compression is located directly below the incident chirped pulse 1 beam and is reflected by the output mirror 6, becoming the compressed output pulse 7, completing the compression. The narrowest compression of the output pulse is measured to be <500 fs, and the compression efficiency is 88%.
[0044] In summary, this invention expands the number of times the compression grating can be used by re-injecting the light that was first output through the compressor into the compressor. This results in a greater compression amount without changing the grating spacing of the compressor, thus allowing for greater broadening of the chirped pulse amplifier, reducing the design limitations of the chirped pulse amplifier, and improving the single-pulse energy output of the femtosecond laser.
[0045] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need further definition and explanation in subsequent figures.
[0046] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.
[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, 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 said element.
Claims
1. A two-way femtosecond laser compressor, characterized in that: It includes a transmission grating (2), a mirror group (3), a mirror (4), a beam-lowering mirror (5), and an output mirror (6); In the first incident light path, the incident chirped pulse (1) is connected to region one (21) of the transmission grating (2), region one (21) of the transmission grating (2) is connected to the mirror group (3), the mirror group (3) is connected to region two (22) of the transmission grating (2), and region two (22) of the transmission grating (2) is connected to the mirror (4). In the first reflection path, the reflector (4) is connected to the second region (22) of the transmission grating (2), the second region (22) of the transmission grating (2) is connected to the reflector group (3), the reflector group (3) is connected to the first region (21) of the transmission grating (2), and the first region (21) of the transmission grating (2) is connected to the beam lowering reflector (5). In the second incident light path, the beam lowering mirror (5) is connected to the third region (23) of the transmission grating (2), the third region (23) of the transmission grating (2) is connected to the mirror group (3), the mirror group (3) is connected to the fourth region (24) of the transmission grating (2), and the fourth region (24) of the transmission grating (2) is connected to the mirror (4). In the second reflection path, the reflector (4) is connected to region four (24) of the transmission grating (2), region four (24) of the transmission grating (2) is connected to the reflector group (3), the reflector group (3) is connected to region three (23) of the transmission grating (2), and region three (23) of the transmission grating (2) is connected to the output reflector (6).
2. The double-pass femtosecond laser compressor of claim 1, wherein: The incident chirped pulse (1) is a chirped pulse with a center wavelength of 1030nm, 1064nm, and 1342nm, an output power of 0 to 1000W, and a pulse width of 100fs to 100ns.
3. The double-pass femtosecond laser compressor of claim 1, wherein: The transmission grating (2) is a transmission grating with a working wavelength in the 1030nm, 1064nm and 1342nm bands and a grating line density of 1 / mm to 10000 / mm.
4. The double-pass femtosecond laser compressor of claim 1, wherein: The reflector group (3) consists of two broadband reflectors arranged orthogonally, with the working wavelength being the output wavelength of the infrared laser.
5. The double-pass femtosecond laser compressor according to claim 1 or 4, wherein: The center-to-center distance between the two lenses of the reflector group (3) is 1mm to 200mm, and the distance between the reflector group (3) and the transmission grating (2) is 0 to 2000mm.
6. The double-pass femtosecond laser compressor of claim 1, wherein: The reflector (4) is a broadband reflector with an operating wavelength of the infrared laser output wavelength.
7. The double-pass femtosecond laser compressor of claim 1, wherein: The beam lowering reflector (5) consists of two orthogonally arranged reflectors, which can increase or decrease the beam height by 0mm to 200mm.
8. The two-way femtosecond laser compressor according to claim 1 or 7, characterized in that: The center-to-center distance between the two lenses of the beam-lowering reflector (5) is 1mm to 200mm, and the distance between the beam-lowering reflector (5) and the transmission grating (2) is 0 to 200mm.