Adjustable spectrum filter and spectrum filtering system with same
By designing an adjustable spectral filter and utilizing a combination of adjusting bolts and light-shielding plates, the problems of complex structure and inflexible spectral adjustment in existing spectral filters are solved, enabling arbitrary adjustment of spectral shape and improvement of pulse quality.
Patent Information
- Application Number
- CN202520365197.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-04
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-03-04
AI Technical Summary
Existing spectral filters have complex structures, making it difficult to achieve arbitrary spectral tuning, and they also suffer from pulse quality issues.
Design an adjustable spectral filter that allows for flexible adjustment of the position and angle of the light-shielding plate by adjusting the combination of bolts and light-shielding plates, thereby adjusting the spectral shape.
Arbitrary adjustment of the spectral shape was achieved, which improved pulse quality and reduced system cost and complexity.
Smart Images
Figure CN223926715U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of spectral filter technology, and in particular to an adjustable spectral filter. Background Technology
[0002] Spectral premodulation, including spectral configuration and phase modulation, is a crucial method for achieving high-quality laser pulse output in ultrafast laser amplification systems (such as chirped pulse amplification). By premodulating the spectral structure of the mode-locked laser pulse entering the amplifier, its spectral phase curve can be effectively altered, thereby flattening it and reducing the gain narrowing effect in fiber amplifiers. Simultaneously, it avoids the excessive nonlinear phase shift introduced by self-phase modulation. Therefore, the amplified pulse can be compressed to the Fourier transform limit while maintaining high pulse contrast.
[0003] Spectral premodulation techniques have been widely applied in ultrafast laser systems such as chirped pulse amplification. Commonly used methods include time-domain electro-optic modulation, birefringent filters, multilayer dielectric filters, spatial light modulators, and modulation using nonlinear effects within optical fibers. For time-domain electro-optic modulation, the output pulse of the mode-locked laser is first broadened, and then the time-domain pulse is shaped using an electro-optic modulator. Based on the Fourier transform relationship between the pulse's time-domain electric field and frequency domain, the frequency-domain spectrum of the pulse is also ultimately shaped. For birefringent filters, due to their polarization-selective transmission characteristics, they can be applied in regenerative amplifiers and form a bandpass filter with an in-cavity polarization controller to achieve spectral modulation. Yuxin Leng et al. applied birefringent filters to a Ti:sapphire regenerative amplifier, effectively overcoming the gain narrowing effect by adjusting the angle of the birefringent filter. The spectral bandwidth of the amplified laser pulse increased from 18 nm to 35 nm, corresponding to a pulse width reduction to 35 fs after compression. Dielectric filters are obtained by depositing dielectric material layers on a substrate. A stack of dielectric films separated by dielectric spacers constitutes a thin filter stack. The spacers are sandwiched between two dielectric film stacks, forming a Fabry-Perot cavity, thus producing a filtering effect. Charles... G. Durfee et al. applied a self-made filter to a Ti:sapphire multipass amplifier and regenerative amplifier, extending the bandwidth of the amplified pulse spectrum to 70-80 nm. For spatial light modulators, spectral modulation controllability is mainly achieved through programmable elements, offering high adjustment precision and allowing for arbitrary adjustment of the spectral shape. In 2021, Duan Yufei et al. successfully increased the spectral width of the amplified signal light from 7 nm to 9 nm by shaping the spectrum of the signal light before amplification using a spatial light modulator, corresponding to a pulse width reduction from 256 fs to 170 fs. By utilizing the nonlinear effects within the optical fiber, the signal light spectrum and pulse can evolve into a parabolic configuration. This spectral shape has a flat spectral phase and avoids excessive accumulation of nonlinear chirp during amplification, thus improving the quality of the amplified and compressed pulse. In 2019, Hong… Chang et al. improved the quality of the signal light pulse after main amplification by designing the parameters of the fiber preamplifier to shape the signal light spectrum into a parabolic configuration. They achieved 1.06 μm ultrafast laser output with a pulse energy of 27 μJ and a pulse width of 172 fs when the system's nonlinear phase shift accumulation was 12 rad.
[0004] Although various spectral premodulation techniques have been developed, existing technologies still have certain shortcomings. For electro-optic modulation techniques and filters, their modulation characteristics are generally fixed, making it difficult to achieve arbitrary spectral modulation shapes. Furthermore, because filters rely on interference effects for mode selection, the quality of the filtered pulse is affected, resulting in strong base and subpulses after chirped pulse amplification and compression. For spatial light modulators, the fill rate of the liquid crystal spatial light modulator limits the spacing between liquid crystal molecules on the entire liquid crystal screen. These spacings lack adjustment capabilities, leading to a significant modulation effect within the liquid crystal spatial light modulator itself. Consequently, the shaped spectral shape is not ideal. For spectral shaping based on nonlinear effects, achieving a parabolic spectral configuration requires precise design of the fiber length and input signal parameters in the fiber preamplifier, making the system design complex. Moreover, the above spectral modulation techniques struggle to achieve adjustments in spectral shape for different levels of precision, thus limiting their application to some extent.
[0005] To address the shortcomings of the aforementioned spectral modulation techniques, this invention proposes a structurally tunable spectral filter that can arbitrarily adjust the shape of the mode-locked laser pulse spectrum with variable adjustment precision. This effectively compensates for the gain narrowing and nonlinear phase shift accumulation problems encountered by pulsed lasers during amplification. Furthermore, due to the simple structure of the modulator itself, it can significantly reduce system cost and complexity. Utility Model Content
[0006] This invention provides an adjustable spectral filter, which solves the technical problem that existing spectral filters have complex structures and are not suitable for shaping various pulsed light waves.
[0007] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: an adjustable spectral filter, comprising: a fixing plate, adjusting bolts, and a light-shielding plate.
[0008] The fixing plate is a long strip structure with multiple adjusting screw holes that pass through the top and bottom ends. The multiple adjusting screw holes are spaced apart along the length of the fixing plate. There are multiple adjusting bolts, each screwed into one of the multiple adjusting screw holes, and the screw-in ends of the multiple adjusting bolts are screwed out of the corresponding adjusting screw holes. There are multiple light-shielding sheets, each detachably connected to the screw-out ends of the multiple adjusting bolts that are screwed out of the adjusting screw holes, so that the position of the light-shielding sheets can be adjusted as the adjusting bolts are rotated.
[0009] The beneficial effects of this utility model are:
[0010] 1. An improved traditional spectral filter structure is achieved by first rotating an adjusting bolt within an adjusting screw hole, and then using light-shielding plates detachably connected to the adjusting bolt. This allows for changing the rotation angle of multiple light-shielding plates while rotating the adjusting bolt, adjusting the gap between adjacent light-shielding plates, lengthening or shortening the length of multiple light-shielding plates extending beyond the adjusting screw hole, and adjusting the intensity of the optical frequency component corresponding to any light spot position. This achieves adjustment of the spectral shape. Unlike liquid crystal spatial light modulators where the fill rate affects the filter, the light-shielding plates can adjust their size to match different light spot sizes, and the spacing between different light-shielding plates can be freely adjusted, ensuring that the filter has adjustment capabilities at all light spot positions.
[0011] 2. The number and size of light-shielding sheets can be configured according to resolution requirements. By increasing the number of light-shielding sheets and reducing the size of each sheet, more precise spectral adjustment can be achieved. Conversely, the precision of spectral adjustment will decrease. The number and size of light-shielding sheets can be flexibly configured for different spectral resolution application scenarios.
[0012] Based on the above technical solution, the present invention can be further improved as follows.
[0013] Furthermore, it also includes locking bolts. The side of the fixing plate is provided with a plurality of locking screw holes that are respectively opposite to and connected to the plurality of adjusting screw holes. There are a plurality of locking bolts, which are respectively screwed into the plurality of locking screw holes. The plurality of locking bolts are respectively screwed into the plurality of locking screw holes and their screw-in ends can all contact the corresponding adjusting bolts.
[0014] The further beneficial effect of adopting the above is that by using the locking bolt to lock the adjusting bolt in the adjusting screw hole, the adjusting bolt can be prevented from shaking, thus improving the stability and firmness of the adjusting bolt.
[0015] Furthermore, the gap between the plurality of light-shielding sheets is 0.1 to 0.2 mm.
[0016] Additionally, a spectral filtering system is provided, comprising: a diffraction grating A, a collimating lens A, a reflecting mirror A, a collimating lens B, and the aforementioned adjustable spectral filter. The collimating lens A is arranged parallel to the upper part of one side of the diffraction grating A; a fixing plate is arranged parallel to the side of the collimating lens A away from the diffraction grating A; the reflecting mirror A is arranged parallel to the side of the fixing plate away from the collimating lens A, and its upper mirror surface A corresponding to the fixing plate is arranged obliquely from top to bottom in a direction away from the fixing plate; the collimating lens B is located parallel to the lower part of the collimating lens A and is arranged parallel to the lower part of one side of the diffraction grating A; the lower mirror surface B corresponding to the collimating lens B is arranged obliquely from bottom to top in a direction away from the collimating lens B; the pulsed light wave first passes sequentially through the upper part of the diffraction grating A, the collimating lens A, and the plurality of light-shielding plates, irradiates the upper mirror surface A, then is reflected onto the lower mirror surface B, and then passes through the collimating lens B before exiting from the lower part of the diffraction grating A.
[0017] The further beneficial effects of the above are as follows: the input pulse light wave is first spatially expanded by the diffraction of the upper diffraction grating A, and then collimated by the collimating lens A; the collimated pulse light wave undergoes spectral shaping under the action of multiple light-shielding plates; and then it is irradiated by the collimating lens B through the reflecting mirror A, and the shaped pulse light wave is emitted from the lower part of the diffraction grating A.
[0018] Additionally, a spectral filtering system is provided, comprising: a diffraction grating B, a collimating lens C, multiple reflective films, a mirror B, a collimating lens D, and the aforementioned adjustable spectral filter. The collimating lens C is arranged parallel to the upper part of one side of the diffraction grating B; the fixing plate is arranged on the side of the collimating lens C away from the diffraction grating B and is arranged obliquely from top to bottom in a direction away from the collimating lens C; the multiple reflective films are respectively attached to the multiple light-shielding films; the mirror B is located below the fixing plate; the collimating lens D is arranged parallel to the lower part of one side of the diffraction grating B; the mirror B is arranged obliquely from bottom to top in a direction away from the collimating lens D; the laser pulse first passes sequentially through the diffraction grating B and the collimating lens C, irradiates the multiple reflective films, then reflects onto the mirror B, and after passing through the collimating lens D, exits from below the diffraction grating B.
[0019] Furthermore, both diffraction grating A and diffraction grating B are transmission diffraction gratings.
[0020] Furthermore, collimating lens A, collimating lens B, collimating lens C, and collimating lens D are all plano-convex lenses.
[0021] Furthermore, reflector A, reflector B, and reflector C are all planar reflectors. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the structure of an adjustable spectral filter according to the present invention;
[0023] Figure 2 This is a schematic diagram of the structure of a spectral filtering system of type 1 according to the present invention;
[0024] Figure 3 This is a schematic diagram of the structure of a type 2 spectral filtering system according to the present invention.
[0025] The attached diagram lists the components represented by each number as follows:
[0026] 1. Fixing plate, 2. Adjusting bolt, 3. Light shield, 4. Locking bolt, 5. Diffraction grating A, 6. Collimating lens A, 7. Reflector A, 8. Collimating lens B, 9. Diffraction grating B, 10. Collimating lens C, 11. Reflector B, 12. Collimating lens D. Detailed Implementation
[0027] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.
[0028] like Figure 1 As shown, an adjustable spectral filter includes: a fixing plate 1, adjusting bolts 2, and a light-shielding plate 3.
[0029] The fixing plate 1 is a long strip structure with multiple adjusting screw holes that pass through the top and bottom. The multiple adjusting screw holes are distributed at intervals along the length of the fixing plate 1. There are multiple adjusting bolts 2, which are screwed into the multiple adjusting screw holes respectively, and the screw-in ends of the multiple adjusting bolts 2 are screwed out of the corresponding adjusting screw holes respectively. There are multiple light-shielding plates 3, which are detachably connected to the screw-out ends of the multiple adjusting bolts 2 so as to adjust the position of the light-shielding plates 3 as the adjusting bolts 2 are rotated.
[0030] like Figure 1 As shown, in some specific embodiments, a locking bolt 4 may also be included. The side of the fixing plate 1 is provided with a plurality of locking screw holes that are respectively opposite to and connected to a plurality of adjusting screw holes. There are a plurality of locking bolts 4, which are respectively screwed into a plurality of locking screw holes. The plurality of locking bolts 4 are respectively screwed into a plurality of locking screw holes and their screw-in ends can all contact the corresponding adjusting bolt 2.
[0031] Specifically, the gap between the multiple light-shielding plates 3 can be 0.1 to 0.2 mm.
[0032] In addition, such as Figure 2As shown, a spectral filtering system is provided, including: a diffraction grating A5, a collimating lens A6, a reflecting mirror A7, a collimating lens B8, and an adjustable spectral filter. The collimating lens A6 is arranged parallel to the upper part of one side of the diffraction grating A5; a fixing plate 1 is arranged parallel to the side of the collimating lens A6 away from the diffraction grating A5; the reflecting mirror A7 is arranged parallel to the side of the fixing plate 1 away from the collimating lens A6, and the upper mirror surface A of the corresponding fixing plate 1 moves from top to bottom in a direction away from the fixing plate 1. The collimating lens B8 is positioned parallel to and below the collimating lens A6, and is also positioned parallel to and below one side of the diffraction grating A5. The reflecting mirror A7 is positioned at an angle from bottom to top, corresponding to the lower mirror surface B of the collimating lens B8, moving away from the collimating lens B8. The pulsed light wave first passes through the upper part of the diffraction grating A5, the collimating lens A6, and multiple light-shielding plates 3 in sequence, then illuminates the upper mirror surface A, and is reflected to the lower mirror surface B. Finally, it passes through the collimating lens B8 and exits from the lower part of the diffraction grating A5.
[0033] In addition, such as Figure 3 As shown, another spectral filtering system is provided, including: a diffraction grating B9, a collimating lens C10, multiple reflective films, a reflector B11, a collimating lens D12, and an adjustable spectral filter. The collimating lens C10 is arranged parallel to the upper part of one side of the diffraction grating B9; the fixing plate 1 is arranged on the side of the collimating lens C10 away from the diffraction grating B9 and is arranged from top to bottom in a direction away from the collimating lens C10; multiple reflective films are respectively attached to multiple light-shielding plates 3; the reflector B11 is located below the fixing plate 1; the collimating lens D12 is arranged parallel to the lower part of one side of the diffraction grating B9; the reflector B11 is arranged from bottom to top in a direction away from the collimating lens D12; the laser pulse first passes through the diffraction grating B9 and the collimating lens C10 in sequence, irradiates the multiple reflective films, then reflects onto the reflector B11, and then passes through the collimating lens D12 before exiting from below the diffraction grating B9.
[0034] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.
Claims
1. An adjustable spectral filter, characterized by, It comprises: a fixed plate (1) which is in a long strip shape and has a plurality of adjusting screw holes penetrating through the top end and the bottom end inside, and the adjusting screw holes are distributed along the length direction of the fixed plate (1); a plurality of adjusting bolts (2) which are screwed into the adjusting screw holes respectively, and the screwing-in ends of the adjusting bolts (2) are screwed out of the corresponding adjusting screw holes respectively; a plurality of light shielding sheets (3) which are detachably connected to the screwing-out ends of the adjusting bolts (2) screwed out of the adjusting screw holes respectively, so as to adjust the positions of the light shielding sheets (3) with the rotation of the adjusting bolts (2).
2. A tunable spectral filter according to claim 1, characterized in that It further comprises locking bolts (4), the side surface of the fixed plate (1) is provided with a plurality of locking screw holes which are opposite to and communicated with the adjusting screw holes respectively; the locking bolts (4) are screwed into the locking screw holes respectively, and the screwing-in ends of the locking bolts (4) are in contact with the corresponding adjusting bolts (2) respectively.
3. The tunable spectral filter of claim 1, wherein, The gap between the light shielding sheets (3) is 0.1-0.2 mm.
4. A spectral filtering system, characterized by, It comprises: a diffraction grating A (5), a collimating lens A (6), a mirror A (7), a collimating lens B (8) and the adjustable spectral filter according to any one of claims 1-3, the collimating lens A (6) is arranged in parallel on the upper side of the diffraction grating A (5); the fixed plate (1) is arranged in parallel on the side of the collimating lens A (6) away from the diffraction grating A (5); the mirror A (7) is arranged in parallel on the side of the fixed plate (1) away from the collimating lens A (6) and the upper mirror surface A of the fixed plate (1) is arranged in sequence from top to bottom and inclined away from the fixed plate (1); the collimating lens B (8) is arranged in parallel below the collimating lens A (6) and on the lower side of the diffraction grating A (5); the lower mirror surface B of the mirror A (7) is arranged in sequence from bottom to top and inclined away from the collimating lens B (8); the pulsed light wave first passes through the upper part of the diffraction grating A (5), the collimating lens A (6) and the plurality of light shielding sheets (3) in sequence, is irradiated onto the upper mirror surface A, is reflected onto the lower mirror surface B, and is emitted from the lower part of the diffraction grating A (5) through the collimating lens B (8).
5. A spectral filtering system, characterized by, It comprises: The diffraction grating B (9), the collimating lens C (10), the multiple reflecting diaphragms, the mirror B (11), the collimating lens D (12) and the adjustable spectral filter according to any one of claims 1-3, the collimating lens C (10) is arranged in parallel on the upper side of the diffraction grating B (9); the fixed plate (1) is arranged on the side of the collimating lens C (10) away from the diffraction grating B (9) and is arranged in sequence from top to bottom and tilted away from the collimating lens C (10); the multiple reflecting diaphragms are respectively pasted on the multiple light-shielding pieces (3); the mirror B (11) is located below the fixed plate (1); the collimating lens D (12) is arranged in parallel on the lower side of the diffraction grating B (9); the mirror B (11) is arranged in sequence from bottom to top and tilted away from the collimating lens D (12); the laser pulse first passes through the diffraction grating B (9) and the collimating lens C (10) in sequence, irradiates on the multiple reflecting diaphragms, is reflected on the mirror B (11), and then passes through the collimating lens D (12) and is emitted from the lower side of the diffraction grating B (9).