Ultra-wideband dispersion modulation device and method based on high-refractive-index material flat window

Abstract

This invention relates to dispersion control devices and methods, specifically to an ultra-wideband dispersion control device and method based on a high-refractive-index material flat plate window. It solves the technical problems of existing dispersion control devices, such as the easy introduction of film-based dispersion and wavefront distortion, limited operating band, and high cost. This invention uses a high-refractive-index material flat plate window as both the beam splitter and combiner, utilizing its intrinsic Fresnel reflection to achieve film-based dispersion-free beam splitting. The beam splitting / combining efficiency is close to the theoretical maximum, with low stress and no film layer deformation. It can completely eliminate GDD oscillations, wavefront distortion, and pulse shape changes caused by traditional chirped dichroic mirrors, improving overall efficiency and achieving high-precision, high-efficiency, and low-dispersion management of ultra-wideband beams. Simultaneously, an independent dispersion control module is used to separately control the dispersion of the two bands of the broadband incident light, which can broaden the operating band and adapt to ultra-wideband mid-infrared pulses.

Description

Technical Field

[0001] This invention relates to dispersion control devices and methods, specifically to an ultrawideband dispersion control device and method based on a high-refractive-index material flat plate window. Background Technology

[0002] Mid-infrared (wavelength 1.5μm-4μm) ultrashort pulses are a core light source for fields such as strong-field physics, attosecond science, molecular fingerprint spectroscopy, and medical diagnostics. To achieve few-period / subperiod pulses, full-band dispersion compensation must be performed on ultra-wideband mid-infrared pulses with spectral widths exceeding octave bands.

[0003] Currently, chirped dichroic mirrors are typically used to segment broadband spectra, followed by dispersion compensation for each segment before beam combining. However, chirped dichroic mirrors are multilayer dielectric films, exhibiting severe GDD oscillations (group delay dispersion oscillations) at the spectral segmentation points. This can easily introduce uncompensated higher-order dispersion, affecting the pulse shape after dispersion compensation. Furthermore, the wider the bandwidth of the broadband spectrum, the thicker the chirped dichroic mirror film becomes. The resulting film stress causes mirror deformation, leading to wavefront distortion and preventing wavefront re-alignment after beam splitting / combining. In addition, custom-made chirped dichroic mirrors are required for beam splitting / combining for different broadband spectra, resulting in high costs and limited operating wavelengths, making further widening difficult. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of existing dispersion control devices, which are prone to introducing film dispersion and wavefront distortion, and have limited operating bands and high costs. The invention provides an ultra-wideband dispersion control device and method based on a high-refractive-index material flat plate window.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An ultra-wideband dispersion control device based on a high-refractive-index material flat plate window is characterized by comprising a high-refractive-index material flat plate beam-splitting window, a first dispersion control module, a first folding mirror group, a second dispersion control module, a second folding mirror group, and a high-refractive-index material flat plate beam-combining window.

[0007] The high-refractive-index material flat beam-splitting window is set in the transmission optical path of broadband incident light to split the broadband incident light into a transmitted beam and a reflected beam.

[0008] The first dispersion control module and the first folding mirror group are sequentially arranged in the transmission optical path of the transmitted beam. The first dispersion control module is used to control the dispersion of the transmitted beam and output a first broadband light of a specific band through spectral filtering within the working band.

[0009] The second folding mirror group is set in the transmission optical path of the reflected beam, and the second dispersion control module is set in the output optical path of the second folding mirror group. It is used to perform dispersion control on the reflected beam and output a second broadband light of a specific band through spectral filtering within the working band.

[0010] The high-refractive-index material flat beam combining window is located at the intersection of the output optical paths of the first folding mirror group and the second dispersion control module. It is used to reflect the first broadband light and transmit the second broadband light, so that the optical paths of the two overlap.

[0011] The first and second folding mirror groups are used to change the transmission optical paths of the first broadband light and the reflected light beam respectively, and to adjust the optical path lengths of the transmitted light beam and the reflected light beam between the high refractive index material plate beam splitting window and the high refractive index material plate beam combining window respectively, so that both are simultaneously incident on the high refractive index material plate beam combining window.

[0012] Furthermore, the surface of the emitted transmitted beam of the high refractive index material flat beam-splitting window is coated with a first antireflection film, which is used to increase the transmittance of the beam with the same working wavelength in the transmitted beam.

[0013] The surface of the high-refractive-index material flat beam combining window into which the second broadband light is incident is coated with a second anti-reflection film. The second anti-reflection film is used to increase the transmittance of the second broadband light beam that is the same as its working wavelength.

[0014] The first antireflective coating operates in the same wavelength band as the first broadband light, and the second antireflective coating operates in the same wavelength band as the second broadband light.

[0015] Furthermore, both the first dispersion control module and the second dispersion control module employ an acousto-optic programmable dispersion filter.

[0016] Furthermore, the high-refractive-index material flat beam-splitting window and the high-refractive-index material flat beam-combining window are made of the same material, namely single-crystal silicon, germanium, ZnSe, or GaAs.

[0017] Furthermore, the high-refractive-index material flat beam-splitting window and the high-refractive-index material flat beam-combining window have the same thickness, ranging from 0.3 mm to 5 mm.

[0018] Furthermore, both the high-refractive-index material flat beam-splitting window and the high-refractive-index material flat beam-combining window are made of single-crystal silicon and have a thickness of 3 mm.

[0019] Furthermore, the operating wavelength of the first dispersion control module is 1450nm-2400nm, and the operating wavelength of the second dispersion control module is 2400nm-3700nm.

[0020] Furthermore, it also includes a piezoelectric displacement platform, on which both the first and second folding mirror groups are mounted. The piezoelectric displacement platform is used to achieve phase time locking by adjusting the displacement of the first and second folding mirror groups through phase jitter feedback.

[0021] This invention also provides a method for ultra-wideband dispersion modulation based on a high-refractive-index material flat plate window, employing the aforementioned ultra-wideband dispersion modulation device based on a high-refractive-index material flat plate window, characterized by the following steps:

[0022] Step 1: The broadband incident light is incident on a high refractive index material flat beam splitting window, which splits it into a transmitted beam and a reflected beam. The transmitted beam is incident on the first dispersion control module, and the reflected beam is incident on the second folding mirror group.

[0023] Step 2: The first dispersion control module performs dispersion control on the transmitted beam and performs spectral filtering within the working band to obtain the first broadband light in a specific band, which is then incident on the first folding mirror group; the first folding mirror group changes the transmission optical path of the first broadband light and adjusts the optical path, so that it is incident on the high refractive index material flat beam combining window.

[0024] Step 3: After the second folding mirror group changes the transmission optical path of the reflected beam and adjusts the optical path, it is incident on the second dispersion control module; the second dispersion control module performs dispersion control on the reflected beam and performs spectral filtering in the working band to obtain the second broadband light in a specific band, and then incident on the high refractive index material flat beam combining window.

[0025] Step 4: A high-refractive-index material flat beam combining window reflects the first broadband light while transmitting the second broadband light, so that the light paths of the two overlap, thus completing the dispersion control.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The ultra-wideband dispersion control device based on a high-refractive-index material flat plate window provided by this invention uses a high-refractive-index material flat plate window as a beam splitting and beam combining element. It utilizes the intrinsic Fresnel reflection to achieve dispersion-free beam splitting. The beam splitting / combining efficiency is close to the theoretical maximum value. Moreover, it has low stress and no film layer deformation. It can completely eliminate GDD oscillation, wavefront distortion and pulse shape change caused by traditional chirped dichroic mirrors, improve the overall efficiency, and achieve high-precision, high-efficiency and low-dispersion management of ultra-wideband beams.

[0028] 2. The ultra-wideband dispersion control device based on a high-refractive-index material flat window provided by the present invention uses an independent dispersion control module to perform dispersion control on two bands of broadband incident light respectively, which can broaden the working band and adapt to ultra-wideband mid-infrared pulses.

[0029] 3. The ultra-wideband dispersion control device based on a high-refractive-index material flat plate window provided by this invention uses an industrial-grade high-refractive-index material flat plate window instead of a traditional custom-made chirped dichroic mirror. It can be adapted to different broadband spectra simply by changing the working band of the dispersion control module, which is lower in cost and easier to mass-produce.

[0030] 4. The ultra-wideband dispersion control device based on a high-refractive-index material flat window provided by the present invention uses a high-refractive-index material flat window with an uncoated reflective surface and a coated transmittance surface, which can increase the transmittance of the beam in the corresponding wavelength band and further improve the system efficiency. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the device structure according to an embodiment of the present invention;

[0032] Figure 2 This is a flowchart of a method according to an embodiment of the present invention;

[0033] The annotations in the attached figures are explained as follows:

[0034] 1-High refractive index material flat beam splitting window, 2-First dispersion control module, 3-First folding mirror group, 4-Second folding mirror group, 5-Second dispersion control module, 6-High refractive index material flat beam combining window, 7-First antireflective coating, 8-Second antireflective coating. Detailed Implementation

[0035] To make the objectives, advantages, and features of the present invention clearer, the following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the ultra-wideband dispersion control device and method based on a high-refractive-index material flat plate window proposed in this invention. In the description of this invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] An ultrawideband dispersion modulation device based on a high-refractive-index material flat window, such as Figure 1 As shown, the assembly includes a high-refractive-index material flat beam-splitting window 1, a first dispersion control module 2, a first folding mirror group 3, a second dispersion control module 5, a second folding mirror group 4, and a high-refractive-index material flat beam-combining window 6. In this embodiment, the high-refractive-index material specifically refers to a material with a refractive index between 2.4 and 4.1.

[0037] A high-refractive-index material flat beam-splitting window 1 is positioned on the transmission optical path of the broadband incident light to split it into a transmitted beam and a reflected beam. A first dispersion control module 2 and a first folding mirror group 3 are sequentially positioned on the transmission optical path of the transmitted beam. The first dispersion control module 2 is used to control the dispersion of the transmitted beam and output a first broadband light of a specific wavelength range through spectral filtering within the working wavelength range. A second folding mirror group 4 is positioned on the transmission optical path of the reflected beam, and a second dispersion control module 5 is positioned on the output optical path of the second folding mirror group 4 to control the dispersion of the reflected beam and output a second broadband light of a specific wavelength range through spectral filtering within the working wavelength range. A high-refractive-index material flat beam-combining window 6 is positioned at the intersection of the output optical paths of the first folding mirror group 3 and the second dispersion control module 5 to reflect the first broadband light and transmit the second broadband light, thereby coinciding their optical paths.

[0038] The first folding mirror group 3 and the second folding mirror group 4 are used to change the transmission optical paths of the first broadband light and the reflected light beam, respectively, and to adjust the optical path lengths of the transmitted light beam and the reflected light beam between the high-refractive-index material flat beam-splitting window 1 and the high-refractive-index material flat beam-combining window 6, respectively, so that both beams are simultaneously incident on the high-refractive-index material flat beam-combining window 6. Both the high-refractive-index material flat beam-splitting window 1 and the high-refractive-index material flat beam-combining window 6 are placed at an angle of 40°-50° to the incident light beam. In this embodiment, both the high-refractive-index material flat beam-splitting window 1 and the high-refractive-index material flat beam-combining window 6 are placed at an angle of 45° to the incident light beam.

[0039] The surface of the high-refractive-index material planar beam-splitting window 1 from which the transmitted beam exits is coated with a first antireflection film 7, which increases the transmittance of the beam with the same operating wavelength as its transmitted beam. The surface of the high-refractive-index material planar beam-combining window 6 from which the second broadband light is incident is coated with a second antireflection film 8, which also increases the transmittance of the second broadband light with the same operating wavelength as its second broadband light. The operating wavelength of the first antireflection film 7 is the same as that of the first broadband light, and the operating wavelength of the second antireflection film 8 is the same as that of the second broadband light. The high-refractive-index material planar beam-splitting window 1 and the high-refractive-index material planar beam-combining window 6 adopt a double-sided structure with no coating on the reflective surface and a corresponding wavelength antireflection film on the transmitting surface, which can achieve ultra-low loss of the transmission channel while ensuring high reflectivity beam splitting.

[0040] Both the first dispersion control module 2 and the second dispersion control module 5 employ an acousto-optic programmable dispersion filter (AOPDF). In this embodiment, to achieve dispersion control in the infrared band (1450nm-3700nm) of the ultra-wideband spectrum, the operating wavelengths of the first dispersion control module 2 and the second dispersion control module 5 are set to 1450nm-2400nm and 2400nm-3700nm, respectively. This allows for independent dispersion control of the light in the 1450nm-2400nm and 2400nm-3700nm bands included in the broadband incident light of the 1450nm-3700nm band, thus overcoming the bandwidth limitation of a single AOPDF. Correspondingly, the operating wavelengths of the first antireflection coating 7 and the second antireflection coating 8 are 1450nm-2400nm and 2400nm-3700nm, respectively. In other embodiments, the operating bands of the first dispersion control module 2 and the second dispersion control module 5, as well as the operating bands of the first antireflection film 7 and the second antireflection film 8, can also be adjusted accordingly based on the required band of broadband incident light.

[0041] The high-refractive-index material planar beam-splitting window 1 and the high-refractive-index material planar beam-combining window 6 are made of the same material, namely monocrystalline silicon, germanium, ZnSe, or GaAs. The thickness of both the high-refractive-index material planar beam-splitting window 1 and the high-refractive-index material planar beam-combining window 6 is the same, ranging from 0.3 mm to 5 mm. In this embodiment, both the high-refractive-index material planar beam-splitting window 1 and the high-refractive-index material planar beam-combining window 6 are made of monocrystalline silicon, and both have a thickness of 3 mm. The high-refractive-index material has high Fresnel reflectivity in the mid-infrared band, making the beam splitting / combining efficiency close to the theoretical maximum of 25%, thus improving the overall transmittance of the device.

[0042] In other embodiments, the ultra-wideband dispersion control device based on a high-refractive-index material flat window also includes a piezoelectric displacement platform. The first folding mirror group 3 and the second folding mirror group 4 are both disposed on the piezoelectric displacement platform. The piezoelectric displacement platform is used to adjust the displacement of the first folding mirror group 3 and the second folding mirror group 4 through phase jitter feedback, thereby achieving phase time locking.

[0043] This embodiment also provides an ultra-wideband dispersion modulation method based on a high-refractive-index material flat plate window, employing the aforementioned ultra-wideband dispersion modulation device based on a high-refractive-index material flat plate window, such as... Figure 2 As shown, it includes the following steps:

[0044] Step 1: The broadband incident light is incident on the high refractive index material flat beam splitting window 1, which splits it into a transmitted beam and a reflected beam. The transmitted beam is then incident on the first dispersion control module 2, and the reflected beam is incident on the second folding mirror group 4.

[0045] Step 2: The first dispersion control module 2 performs dispersion control on the transmitted beam and performs spectral filtering within the working band to obtain the first broadband light in a specific band, which is then incident on the first folding mirror group 3. The first folding mirror group 3 changes the transmission optical path of the first broadband light and adjusts the optical path, so that it is incident on the high refractive index material flat beam combining window 6.

[0046] Step 3: After the second folding mirror group 4 changes the transmission optical path of the reflected beam and adjusts the optical path, it is incident on the second dispersion control module 5. The second dispersion control module 5 performs dispersion control on the reflected beam and performs spectral filtering in the working band to obtain a second broadband light in a specific band, and then incident on the high refractive index material flat beam combining window 6.

[0047] Step 4: The high-refractive-index material flat beam combining window 6 reflects the first broadband light and transmits the second broadband light at the same time, so that the light paths of the two overlap, thus completing the dispersion control.

[0048] This invention is based on the Mach-Zehnder interferometer architecture, using low-dispersion, high-stability, high-refractive-index windows to construct interferometer arms, achieving segmented dispersion control and coherent combining of ultra-wideband spectra. High-refractive-index flat windows are used as both beam-splitting and beam-combining elements. The reflective surfaces are uncoated, while the transmitting surfaces are coated with anti-reflection films for the corresponding wavelength bands. Intrinsic Fresnel reflection is utilized to achieve dispersion-free broadband spectral splitting, dividing the broadband incident light into two bands: 1450nm-2400nm and 2400nm-3700nm. Dispersion is independently controlled by acousto-optically programmable dispersion filters (AOPDFs) for each band, and then combined and output through high-refractive-index flat windows. This completely eliminates group delay dispersion oscillations, wavefront distortion, and pulse shape changes caused by traditional chirped dichroic mirrors. Meanwhile, the overall system efficiency is improved, enabling high-precision, high-efficiency, and low-dispersion management of ultra-wideband pulses with a frequency band of 1450nm-3700nm or more. It is suitable for systems such as mid-infrared parametric amplification, sub-periodic pulse generation, strong field physics, and molecular spectroscopy.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. An ultra-broadband dispersion control device based on high refractive index material flat window sheet, characterized in that: It includes a high-refractive-index material flat beam splitting window (1), a first dispersion control module (2), a first folding mirror group (3), a second dispersion control module (5), a second folding mirror group (4), and a high-refractive-index material flat beam combining window (6). The high refractive index material flat beam splitting window (1) is set in the transmission optical path of broadband incident light to split the broadband incident light into a transmitted beam and a reflected beam. The first dispersion control module (2) and the first folding mirror group (3) are sequentially arranged in the transmission optical path of the transmitted beam. The first dispersion control module (2) is used to perform dispersion control on the transmitted beam and output the first broadband light of a specific band through spectral filtering within the working band. The second folding mirror group (4) is set in the transmission optical path of the reflected beam, and the second dispersion control module (5) is set in the output optical path of the second folding mirror group (4) to perform dispersion control on the reflected beam and output a second broadband light of a specific band through spectral filtering within the working band. The high refractive index material flat beam combining window (6) is set at the intersection of the output light paths of the first folding mirror group (3) and the second dispersion control module (5) to reflect the first broadband light and transmit the second broadband light, so that the light paths of the two overlap. The first folding mirror group (3) and the second folding mirror group (4) are used to change the transmission optical path of the first broadband light and the reflected light beam respectively, and adjust the optical path of the transmitted light beam and the reflected light beam between the high refractive index material plate beam splitting window (1) and the high refractive index material plate beam combining window (6) respectively, so that the two beams are simultaneously incident on the high refractive index material plate beam combining window (6).

2. The ultrawideband dispersion control device based on a high-refractive-index material flat window according to claim 1, characterized in that: The surface of the high refractive index material flat beam splitter window (1) from which the transmitted beam is emitted is coated with a first antireflection film (7), which is used to increase the transmittance of the transmitted beam in the beam that is the same as its working band. The surface of the high refractive index material flat beam combining window (6) on which the second broadband light is incident is coated with a second antireflection film (8). The second antireflection film (8) is used to increase the transmittance of the second broadband light beam that is the same as its working wavelength. The first antireflective coating (7) operates in the same wavelength band as the first broadband light, and the second antireflective coating (8) operates in the same wavelength band as the second broadband light.

3. The ultrawideband dispersion control device based on a high-refractive-index material flat window according to claim 2, characterized in that: Both the first dispersion control module (2) and the second dispersion control module (5) adopt an acousto-optic programmable dispersion filter.

4. The ultrawideband dispersion control device based on a high-refractive-index material flat window according to claim 3, characterized in that: The high-refractive-index material flat beam splitting window (1) and the high-refractive-index material flat beam combining window (6) are made of the same material, namely single-crystal silicon, germanium, ZnSe or GaAs.

5. The ultrawideband dispersion control device based on a high-refractive-index material flat window according to claim 4, characterized in that: The high-refractive-index material flat beam splitting window (1) and the high-refractive-index material flat beam combining window (6) have the same thickness, ranging from 0.3 mm to 5 mm.

6. The ultrawideband dispersion control device based on a high-refractive-index material flat window according to claim 5, characterized in that: The high-refractive-index material flat beam splitting window (1) and the high-refractive-index material flat beam combining window (6) are both made of single-crystal silicon and have a thickness of 3 mm.

7. The ultrawideband dispersion control device based on a high-refractive-index material flat window according to claim 6, characterized in that: The first dispersion control module (2) operates in the wavelength range of 1450nm-2400nm, and the second dispersion control module (5) operates in the wavelength range of 2400nm-3700nm.

8. The ultrawideband dispersion control device based on a high-refractive-index material flat window according to claim 7, characterized in that: It also includes a piezoelectric displacement platform, on which the first folding mirror group (3) and the second folding mirror group (4) are both set. The piezoelectric displacement platform is used to adjust the displacement of the first folding mirror group (3) and the second folding mirror group (4) through phase jitter feedback to achieve phase time locking.

9. A method for ultra-wideband dispersion control based on a high-refractive-index material flat plate window, employing the ultra-wideband dispersion control device based on a high-refractive-index material flat plate window as described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1: The broadband incident light is incident on the high refractive index material plate beam splitting window (1). The high refractive index material plate beam splitting window (1) splits it into a transmitted beam and a reflected beam. The transmitted beam is incident on the first dispersion control module (2), and the reflected beam is incident on the second folding mirror group (4). Step 2: The first dispersion control module (2) performs dispersion control on the transmitted beam and performs spectral filtering within the working band to obtain the first broadband light in a specific band and then directs it to the first folding mirror group (3); the first folding mirror group (3) changes the transmission optical path of the first broadband light and adjusts the optical path, and then directs it to the high refractive index material flat beam combining window (6). Step 3: The second folding mirror group (4) changes the transmission optical path of the reflected beam and adjusts the optical path, and then it is incident on the second dispersion control module (5); the second dispersion control module (5) performs dispersion control on the reflected beam and performs spectral filtering in the working band to obtain the second broadband light in a specific band, and then it is incident on the high refractive index material flat beam combining window (6). Step 4: The high-refractive-index material flat beam combining window (6) reflects the first broadband light and transmits the second broadband light at the same time, so that the light paths of the two overlap and the dispersion is controlled.

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