Device and method for splitting ultrashort laser pulse according to wavelength
By using conventional optical elements, the ultra-short laser pulse space is dispersed into multiple beams of light of different wavelengths, and beam splitting through convex lens arrays and gratings, the problems of complex beam splitting operations, high cost and insufficient flexibility in the prior art are solved, and efficient and flexible wavelength beam splitting effects are achieved.
Patent Information
- Application Number
- CN202510361651.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2025-06-27
AI Technical Summary
In the beam splitting operation of ultra-short laser pulses, the problem of customized optical components is complicated, the cost is high, the group speed dispersion mismatch is easy to introduce, the fixed optical path is difficult to dynamically adjust the beam splitting ratio, insufficient flexibility and large energy loss.
Using conventional optical elements, the ultra-short laser pulse space is dispersed into multiple beams of light of different wavelengths through the first grating, and the light in each region is divided into multiple regions according to the wavelength using the first convex lens and the first convex lens array. The light in each region is concentrated to the second grating, and the multiple converged light is converted into multiple parallel light pulses with different spectral ranges through the second grating, and finally beam splitting is achieved in space through the exit element.
It realizes flexible and precise wavelength beam splitting of ultra-short laser pulses, has a simple structure, low energy loss, and does not introduce group speed dispersion mismatch. It is suitable for ultrafast imaging systems, multi-spectral detection, hyperspectral cameras and other fields.
Smart Images
Figure CN120215128A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of laser pulse shaping, and particularly relates to an ultrashort laser pulse beam splitting device and method according to wavelength. Background Technique
[0002] Ultrashort laser pulses (with pulse widths in the femtosecond to picosecond range) have become core tools in the fields of physics, chemistry, biology, and industry due to their extremely short time-domain characteristics, ultra-high peak power (in the TW range), and broad spectral range (40 - 100 nm). Their broad spectral characteristics stem from the Fourier transform coupling effect between the time domain and the frequency domain, and are irreplaceable in ultrafast dynamics detection, nonlinear spectroscopy, and sub-micron precision micromachining. To achieve precise control of the pulse spectral components, beam splitting technology is particularly important. For example, separating wavelength information in hyperspectral imaging or avoiding optical path interference in multi-parameter pump-probe experiments all require wavelength beam splitting to achieve multi-channel independent regulation.
[0003] For the beam splitting operation of ultrashort laser pulses, generally, beam splitters can be used for polarization beam splitting, non-polarization beam splitting, etc. However, in many application scenarios, the spectral information of ultrashort laser pulses is very important for precisely controlling the properties of the laser. The technology of beam splitting according to wavelength can accurately separate components of different frequencies, facilitating multi-channel laser operation, and is applied in fields such as ultrafast optical imaging and hyperspectral cameras.
[0004] Currently, traditional wavelength beam splitting technologies rely on grating dispersion combined with customized optical elements (such as periscope arrays or shearing mirrors), but there are significant limitations: the processing of customized elements is complex, the cost is high, and group velocity dispersion mismatch is easily introduced; the fixed optical path is difficult to dynamically adjust the beam splitting ratio, lacking flexibility; multi-stage reflection results in an energy loss exceeding 30%, restricting applications in high-power scenarios. These problems severely limit the practical progress of ultrashort pulses in frontier fields such as tunable optical systems and coherent synthesis devices. Therefore, a technology using conventional optical elements and having a simple structure is needed to split ultrashort laser pulses according to wavelength in space. Summary of the Invention
[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide an ultrashort laser pulse beam splitting device and method according to wavelength, which can achieve beam splitting of ultrashort laser pulses according to wavelength by using conventional optical elements, has a simple structure, extremely high flexibility, low energy loss, and does not introduce group velocity dispersion mismatch.
[0006] The present invention provides the following technical solutions: In the first aspect, there is provided an ultrashort laser pulse beam splitting device according to wavelength, including, arranged in sequence along the optical path: An ultrashort pulse laser for generating ultrashort laser pulses; The first grating, which is used to spatially disperse an ultrashort laser pulse into multiple beams of light with different wavelengths; The first convex lens, which is used to make multiple beams of light with different wavelengths propagate in a parallel trend; The first convex lens array, which is used to divide the light propagating in a parallel trend into multiple regions according to the wavelength, and converge the light in each region to the second grating; The second grating, which is used to convert multiple converging light beams into multiple parallel light pulses with different spectral ranges; The second convex lens, which is used to make multiple parallel light pulses propagate in a parallel trend; The output element, which is used to output multiple parallel light pulses propagating in a parallel trend, and achieve beam splitting in space.
[0007] Further, the ruling density of the first grating and the second grating is the same.
[0008] Further, the distance between the first grating and the first convex lens is the same as the focal length of the first convex lens.
[0009] Further, the first convex lens array is composed of multiple first sub-lenses arranged in a 1*n array, where n is the number of the first sub-lenses; the focal length of the first sub-lens is the same as the focal length of the first convex lens.
[0010] Further, the distance between the first convex lens array and the first convex lens is twice the focal length of the first convex lens.
[0011] Further, the focal length of the second convex lens is greater than the focal length of the first convex lens, and the distance between the second convex lens and the second grating is the difference between the focal length of the second convex lens and the focal length of the first convex lens.
[0012] Further, the output element is a second convex lens array, which is used to output multiple parallel light pulses propagating in a parallel trend in parallel, and achieve beam splitting in space; The second convex lens array is composed of multiple second sub-lenses arranged in a 1*N array, where N is the number of the second sub-lenses, and N = n; And / or, the focal length of the second sub-lens is the same as the focal length of the second convex lens; And / or, the distance between the second convex lens array and the second convex lens is twice the focal length of the second convex lens.
[0013] Further, the output element is a third convex lens, which is used to converge multiple parallel light pulses propagating in a parallel trend to the rear focal plane of the third convex lens at corresponding angles, and then continue to diverge and output, and achieve beam splitting in space; The focal length of the third convex lens is the same as the focal length of the second convex lens; And / or, the distance between the third convex lens and the second convex lens is 2 times the focal length of the second convex lens.
[0014] In a second aspect, a method for splitting an ultrashort laser pulse by wavelength is provided, including the following steps: An ultrashort laser pulse generated by an ultrashort pulse laser is incident on a first grating, and the first grating spatially disperses the ultrashort laser pulse into multiple beams of light with different wavelengths; The multiple beams of light with different wavelengths pass through a first convex lens to make them propagate in a parallel trend; The light propagating in a parallel trend passes through a first convex lens array to divide it into multiple regions according to wavelength. The light in each region converges to a second grating, and the second grating converts the multiple beams of converging light into multiple parallel light pulses with different spectral ranges and continues to propagate at corresponding diffraction angles; The multiple beams of parallel light pulses pass through a second convex lens to make them propagate in a parallel trend; The multiple beams of parallel light pulses propagating in a parallel trend are emitted through an output element to achieve beam splitting in space.
[0015] Further, the step of emitting the multiple beams of parallel light pulses propagating in a parallel trend through an output element includes: The multiple beams of parallel light pulses propagating in a parallel trend are emitted in parallel through a second convex lens array; Or, the multiple beams of parallel light pulses propagating in a parallel trend pass through a third convex lens to converge at the rear focal plane of the third convex lens at corresponding angles and then continue to diverge and be emitted.
[0016] Compared with the prior art, the beneficial effects of the present invention are: The ultrashort laser pulse splitting device and method by wavelength provided by the present invention spatially disperse an ultrashort laser pulse into multiple beams of light with different wavelengths through a first grating, make the light propagate in a parallel trend through a first convex lens, divide the light into multiple regions according to wavelength through a first convex lens array, converge the light in each region to a second grating, convert the multiple beams of converging light into multiple parallel light pulses with different spectral ranges through the second grating, make the parallel light pulses propagate in a parallel trend through a second convex lens, and finally emit them through an output element to achieve beam splitting in space; all the components used are conventional optical components, with a simple structure, extremely high flexibility, low energy loss, and no group velocity dispersion mismatch introduced; it can be applied to multiple fields such as ultrafast imaging systems, multispectral detection, and hyperspectral cameras, and has great application potential. Description of the Drawings
[0017] Figure 1 It is a schematic structural diagram of the ultrashort laser pulse splitting device by wavelength in Embodiment 1 of the present invention; Figure 2 It is a schematic structural diagram of the first convex lens array in the embodiment of the present invention; Figure 3 It is a schematic structural diagram of the ultrashort laser pulse beam splitting device by wavelength in Embodiment 3 of the present invention; The markings in the figure are: 101, ultrashort pulse laser; 102, first grating; 103, first convex lens; 104, first convex lens array; 105, second grating; 106, second convex lens; 107, second convex lens array; 108, third convex lens. Detailed implementation manners
[0018] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.
[0019] In the description of the present invention, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.
[0020] Embodiment 1
[0021] As Figure 1 shown, this embodiment provides an ultrashort laser pulse beam splitting device by wavelength, including an ultrashort pulse laser 101, a first grating 102, a first convex lens 103, a first convex lens array 104, a second grating 105, a second convex lens 106, and a second convex lens array 107 arranged in sequence along the optical path.
[0022] The ultrashort pulse laser 101 is used to generate ultrashort laser pulses.
[0023] The first grating 102 is used to spatially disperse the ultrashort laser pulses into multiple beams of light with different wavelengths. In this embodiment, the grating density of the first grating 102 is 1200 lp / mm.
[0024] The first convex lens 103 is used to propagate the multiple beams of light with different wavelengths in a parallel trend. The focal length of the first convex lens 103 is f1, and the distance between the first convex lens 103 and the first grating 102 is the same as the focal length of the first convex lens 103, which is also f1. In this embodiment, f1 = 200 mm.
[0025] The first convex lens array 104 is used to divide the light propagating in a parallel trend into multiple regions according to wavelength and converge the light in each region to the second grating 105. As Figure 2As shown in the figure, the first convex lens array 104 is composed of multiple first sub-lenses arranged in a 1*n array, where n is the number of the first sub-lenses; the focal length of the first sub-lens is the same as that of the first convex lens 103, which is also f1; the distance between the first convex lens array 104 and the first convex lens 103 is 2 times the focal length of the first convex lens 103, that is, 2f1. In this embodiment, the first convex lens array 104 is a 1*10 array.
[0026] The second grating 105 is used to convert multiple converging light beams into multiple parallel light pulses with different spectral ranges. The grating line densities of the first grating 102 and the second grating 105 are the same. The distance between the second grating 105 and the first convex lens array 104 is the same as the focal length of the first convex lens 103, that is, f1 = 200 mm.
[0027] The second convex lens 106 is used to propagate multiple parallel light pulses in a parallel trend. The focal length f2 of the second convex lens 106 is greater than the focal length f1 of the first convex lens 103. The distance between the second convex lens 106 and the second grating 105 is the difference between the focal length f2 of the second convex lens 106 and the focal length f1 of the first convex lens 103, that is, f2 - f1. In this embodiment, f2 = 250 mm.
[0028] The second convex lens array 107 is used to emit multiple parallel light pulses propagating in a parallel trend in parallel, realizing beam splitting in space. The second convex lens array 107 is composed of multiple second sub-lenses arranged in a 1*N array, where N is the number of the second sub-lenses, and N = n = 10; the focal length of the second sub-lens is the same as that of the second convex lens 106, that is, f2; the distance between the second convex lens array 107 and the second convex lens 106 is 2 times the focal length of the second convex lens 106, that is, 2f2.
[0029] Embodiment 2
[0030] This embodiment provides a method for splitting ultrashort laser pulses by wavelength based on the device described in Embodiment 1, including the following steps: Step 1, spatial dispersion and collimation of ultrashort laser pulses.
[0031] The ultrashort pulse laser 101 emits Gaussian pulses with a central wavelength of 800 nm (spectral full width at half maximum of 40 nm and pulse width of 40 fs), which is incident on the first grating 102 for first-order diffraction. The first grating 102 spatially disperses the ultrashort laser pulses into multiple light beams with different wavelengths. Subsequently, the multiple light beams with different wavelengths are collimated into parallel light beams by the first convex lens 103, and propagate in a parallel trend, and different wavelength components are linearly distributed in the transverse space.
[0032] Step 2, spectral splitting and secondary diffraction control.
[0033] A first convex lens array 104 is placed in the Fourier plane of the collimated optical path (i.e., at a distance twice the focal length of the first convex lens 103, i.e., at 2f1 = 400 mm). The light propagating in a parallel trend passes through the first convex lens array 104 (a 1*10 array). This array divides the dispersion spectrum into 10 regions according to wavelength, with each region corresponding to a 4-nm bandwidth. Each first sub-lens converges the light in the corresponding region onto the surface of the second grating 105. The second grating 105 performs secondary diffraction on each beam of light to eliminate the wavefront tilt of the first-order dispersion, converting the 10 converging beams of light into 10 parallel light pulses with different spectral ranges. The central wavelength of each beam is spaced 4 nm apart (from 780 - 784 nm to 816 - 820 nm), and the diffraction direction separation is achieved by adjusting the grating incident angle, causing it to continue propagating at the corresponding diffraction angle.
[0034] Step 3: Collimation and emission.
[0035] The 10 parallel light pulses pass through the second convex lens 106 to correct the geometric distortion of the beam transmission path, causing it to propagate in a parallel trend. Finally, the 10 parallel light pulses propagating in a parallel trend pass through the second convex lens array 107 (a 1*10 array), distributing the light beams of each wavelength parallelly into 10 spatial channels to achieve beam splitting in space.
[0036] Embodiment 3
[0037] As Figure 3 shown, this embodiment provides an ultrashort laser pulse wavelength beam splitter, which includes an ultrashort pulse laser 101, a first grating 102, a first convex lens 103, a first convex lens array 104, a second grating 105, a second convex lens 106, and a third convex lens 108 arranged in sequence along the optical path.
[0038] The ultrashort pulse laser 101 is used to generate ultrashort laser pulses.
[0039] The first grating 102 is used to spatially disperse the ultrashort laser pulses into multiple beams of light with different wavelengths. In this embodiment, the grating line density of the first grating 102 is 1800 lp / mm.
[0040] The first convex lens 103 is used to propagate the multiple beams of light with different wavelengths in a parallel trend. The focal length of the first convex lens 103 is f1, and the distance between the first convex lens 103 and the first grating 102 is the same as the focal length of the first convex lens 103, also f1. In this embodiment, f1 = 150 mm.
[0041] The first convex lens array 104 is used to divide the light propagating in a parallel trend into multiple regions according to wavelength and converge the light in each region onto the second grating 105. As Figure 2As shown in the figure, the first convex lens array 104 is composed of multiple first sub-lenses arranged in a 1*n array, where n is the number of the first sub-lenses; the focal length of the first sub-lens is the same as that of the first convex lens 103, which is also f1; the distance between the first convex lens array 104 and the first convex lens 103 is 2 times the focal length of the first convex lens 103, that is, 2f1. In this embodiment, the first convex lens array 104 is a 1*16 array.
[0042] The second grating 105 is used to convert multiple converging light beams into multiple parallel light pulses with different spectral ranges. The grating line densities of the first grating 102 and the second grating 105 are the same, and the distance between the second grating 105 and the first convex lens array 104 is the same as the focal length of the first convex lens 103, that is, f1 = 150 mm.
[0043] The second convex lens 106 is used to make multiple parallel light pulses propagate in a parallel trend. The focal length f2 of the second convex lens 106 is greater than the focal length f1 of the first convex lens 103, and the distance between the second convex lens 106 and the second grating 105 is the difference between the focal length f2 of the second convex lens 106 and the focal length f1 of the first convex lens 103, that is, f2 - f1. In this embodiment, f2 = 200 mm.
[0044] The third convex lens 108 is used to converge multiple parallel light pulses propagating in a parallel trend at corresponding angles onto the rear focal plane of the third convex lens 108, and then continue to diverge and emit, realizing beam splitting in space. The focal length of the third convex lens 108 is the same as that of the second convex lens 106, both are f2; the distance between the third convex lens 108 and the second convex lens 106 is 2 times the focal length of the second convex lens 106, that is, 2f2.
[0045] Embodiment 4
[0046] This embodiment provides a method for splitting ultrashort laser pulses by wavelength based on the device described in Embodiment 3, including the following steps: Step 1, spatial dispersion and collimation of ultrashort laser pulses.
[0047] The ultrashort pulse laser 101 emits a Gaussian pulse with a central wavelength of 800 nm (spectral full width at half maximum of 100 nm and pulse width of 25 fs), which is incident on the first grating 102 for first-order diffraction. The first grating 102 spatially disperses the ultrashort laser pulse into multiple light beams with different wavelengths. Subsequently, multiple light beams with different wavelengths are collimated into parallel light beams by the first convex lens 103, propagate in a parallel trend, and different wavelength components are linearly distributed in the transverse space.
[0048] Step 2, spectral splitting and secondary diffraction regulation.
[0049] The light propagated in a parallel trend as described above passes through the first convex lens array 104 (1*16 array). This array divides the dispersion spectrum into 16 regions according to wavelength, with each region corresponding to a bandwidth of 6.25 nm. Each first sub-lens converges the light in the corresponding region onto the surface of the second grating 105. The second grating 105 performs secondary diffraction on each beam of light to eliminate the wavefront tilt of the first-order dispersion, converting the 16 converged light beams into 16 parallel light pulses with different spectral ranges. The central wavelength of each beam is spaced 6.25 nm apart (from 750 - 756.25 nm to 813.75 - 850 nm), and the diffraction direction separation is achieved by adjusting the incident angle of the grating, causing the light to continue propagating at the corresponding diffraction angle.
[0050] Step 3: Collimation and emission.
[0051] Pass the 10 parallel light pulses through the second convex lens 106 to correct the geometric distortion of the beam transmission path and make them propagate in a parallel trend. Finally, pass the multiple parallel light pulses propagating in a parallel trend through the third convex lens 108, causing them to converge at the rear focal plane of the third convex lens 108 at corresponding angles and then continue to diverge and emit, achieving beam splitting in space.
[0052] In the present invention, the number of split beams of the ultrashort laser pulse is determined by the number of sub-lenses in the convex lens array. Therefore, in some other embodiments, it can be extended to different channels by replacing the array. For example, a 1*30 array can split 30 beams.
[0053] In the present invention, there are no special restrictions on the parameter selection of each component (such as the output parameters of the ultrashort pulse laser, the grating line density, the focal length f1, the focal length f2, etc.). In the specific implementation, the selected parameters are those commonly used in general systems, and the parameters can be changed according to actual needs without affecting the function realization of the device.
[0054] The ultrashort laser pulse beam splitting device and method provided by the present invention spatially disperses the ultrashort laser pulse into multiple beams of light with different wavelengths through the first grating, makes the light propagate in a parallel trend through the first convex lens, divides the light into multiple regions according to wavelength through the first convex lens array, converges the light in each region onto the second grating, converts the multiple converged light beams into multiple parallel light pulses with different spectral ranges through the second grating, makes the parallel light pulses propagate in a parallel trend through the second convex lens, and finally emits through the emission element, achieving beam splitting in space. All the components used are conventional optical components, with a simple structure, extremely high flexibility, low energy loss, and no group velocity dispersion mismatch introduced. It can be applied to multiple fields such as ultrafast imaging systems, multispectral detection, and hyperspectral cameras, and has great application potential.
[0055] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.
Claims
1. An ultrashort laser pulse wavelength splitting device, characterized in that: Including arranged in sequence along the light path: Ultrashort pulse laser, used to generate ultrashort laser pulses; A first grating, used for spatially dispersing an ultrashort laser pulse into multiple beams of light with different wavelengths; The first convex lens is used to propagate multiple beams of light with different wavelengths in a parallel trend; A first convex lens array is used to divide the light propagating in a parallel trend into a plurality of regions according to the wavelength, and converge the light in each region to the second grating; A second grating is used to convert the multiple beams of convergent light into multiple beams of parallel light pulses with different spectral ranges; The second convex lens is used to propagate the multiple parallel light pulses in a parallel trend; The output element is used to output multiple parallel light pulses that propagate in parallel and realize beam splitting in space.
2. The ultrashort laser pulse wavelength splitting device according to claim 1, characterized in that: The first grating and the second grating have the same line density.
3. The ultrashort laser pulse wavelength splitting device according to claim 1, characterized in that: The distance between the first grating and the first convex lens is the same as the focal length of the first convex lens.
4. The ultrashort laser pulse wavelength splitting device according to claim 1, characterized in that: The first convex lens array is composed of a plurality of first sub-lenses arranged in 1*n order, wherein n is the number of the first sub-lenses; and the focal length of the first sub-lenses is the same as that of the first convex lens.
5. The ultrashort laser pulse wavelength splitting device according to claim 1, characterized in that: The distance between the first convex lens array and the first convex lens is twice the focal length of the first convex lens.
6. The ultrashort laser pulse wavelength splitting device according to claim 1, characterized in that: The focal length of the second convex lens is greater than that of the first convex lens, and the distance between the second convex lens and the second grating is the difference between the focal length of the second convex lens and the focal length of the first convex lens.
7. The ultrashort laser pulse wavelength splitting device according to claim 4, characterized in that: The emission element is a second convex lens array, which is used to emit multiple parallel light pulses that propagate in parallel in parallel, and realize beam splitting in space; The second convex lens array is composed of a plurality of second sub-lenses arranged in 1*N order, wherein N is the number of the second sub-lenses, and N=n; And / or, the focal length of the second sub-lens is the same as the focal length of the second convex lens; And / or, the distance between the second convex lens array and the second convex lens is twice the focal length of the second convex lens.
8. The ultrashort laser pulse wavelength splitting device according to claim 1, characterized in that: The emission element is a third convex lens, which is used to converge multiple parallel light pulses propagating in parallel at corresponding angles on the rear focal plane of the third convex lens, and then continue to diverge and emit, so as to realize beam splitting in space; The focal length of the third convex lens is the same as the focal length of the second convex lens; And / or, the distance between the third convex lens and the second convex lens is twice the focal length of the second convex lens.
9. A method for splitting ultrashort laser pulses by wavelength, characterized in that: The following steps are involved: An ultrashort laser pulse generated by an ultrashort pulse laser is incident on a first grating, and the first grating spatially disperses the ultrashort laser pulse into multiple beams of light with different wavelengths; Pass multiple beams of light with different wavelengths through the first convex lens to make them propagate in a parallel trend; The light propagating in a parallel trend passes through the first convex lens array, so that it is divided into multiple regions according to the wavelength, and the light in each region is converged to the second grating. The second grating converts the multiple beams of converged light into multiple beams of parallel light pulses with different spectral ranges, and continues to propagate according to the corresponding diffraction angle; Passing multiple parallel light pulses through a second convex lens to make them propagate in a parallel trend; Multiple parallel light pulses that propagate in parallel are emitted through the output element to achieve beam splitting in space.
10. The method for splitting ultrashort laser pulses by wavelength according to claim 9, characterized in that: The method of emitting a plurality of parallel light pulses propagating in a parallel trend through an emission element comprises: The multiple parallel light pulses propagating in a parallel trend are emitted in parallel through the second convex lens array; Alternatively, multiple parallel light pulses propagating in parallel are passed through a third convex lens so as to converge at a rear focal plane of the third convex lens at a corresponding angle and then continue to diverge and emit.