CN208672830U - The unrelated reflective dielectric grating of polarization based on refractive index regulation film - Google Patents
The unrelated reflective dielectric grating of polarization based on refractive index regulation film Download PDFInfo
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- CN208672830U CN208672830U CN201820909793.2U CN201820909793U CN208672830U CN 208672830 U CN208672830 U CN 208672830U CN 201820909793 U CN201820909793 U CN 201820909793U CN 208672830 U CN208672830 U CN 208672830U
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Abstract
The utility model relates to a kind of unrelated reflective dielectric gratings of polarization based on refractive index regulation film, belong to optical field, the grating includes substrate 1 and grating layer 4, and successively plating is formed with reflectance coating 2, oxide dielectric film articulamentum 3 on substrate 1, and in grating layer etched diffraction grating slot structure；The reflectance coating 2 is that refractive index regulates and controls dielectric multi-layer optical thin film, and it includes high-index material film 2-1 and low-index material film 2-2 which, which regulates and controls dielectric multi-layer optical thin film 2,.The central wavelength of polarization unrelated reflecting medium grating provided by the utility model based on refractive index regulation film is 1064 nanometers, it is -1 grade of Littrow angle in incident angle, -1 grade of diffraction efficiency on the polarization direction TE, TM can be made to be higher than 99% simultaneously in 1050~1080 nanometer ranges, maximum diffraction efficiency is higher than 99.5% in wave band, and the high efficiency diffraction for polarizing unrelated incident light may be implemented.
Description
Technical field
The utility model relates to optical fields, especially a kind of to regulate and control film, central wavelength in near-infrared based on refractive index
The high incisure density of wave band polarizes unrelated reflective gratings.
Background technique
At present in high power laser system, the output power of single laser will receive the factors such as nonlinear effect, thermal damage
Limitation, be difficult to realize high power laser light output.The function in unit area can be effectively promoted using Spectral beam combining beam combination technology
Rate density is one of the effective technical way of improving laser system output power.Wherein realize the common of high efficiency Spectral beam combining
Technology Ways are to realize to be total to different wave length beamlet under the conditions of certain incidence using the dispersion characteristics of reflective dielectric grating
Aperture synthetic.But for such method, the light that the single laser device of beam to be closed is issued is non-polarized light, is both polarized comprising TE
Ingredient includes TM polarized component again, therefore to realize efficient Spectral beam combining, and reflective dielectric grating needs inclined to both
Vibration ingredient all realizes higher diffraction efficiency.In addition, also needing in chirped pulse amplification technique with the high diffraction of wide spectrum
The reflecting grating of efficiency, grating also require to realize high diffraction efficiency for TE polarized component and TM polarized component.
For being applied to the reflecting medium film grating of Spectral beam combining and chirped pulse amplification, generally require with relatively high
Incisure density, it is this under the conditions of reflecting medium film screen periods be sub-wavelength magnitude, show diffraction properties very strong
It is polarization correlated, realize that the design of the unrelated grating of polarization of high-diffraction efficiency has larger difficulty in certain bandwidth range.
Moreover, sub-wavelength period grating diffration characteristic can not be calculated with scalar optical grating diffraction equation.Utilize rigorous couple-wave analysis
Method can accurately calculate sub-wavelength period grating diffration characteristic, can be to grating in conjunction with genetic Optimization Algorithm
Structure optimizes.
Utility model content
The utility model provides a kind of unrelated reflective gratings of all dielectric polarization for 1064nm central wavelength.The grating
Incisure density is 1300 lines/mm, which is directed to the incident light of two kinds of polarization modes of TE and TM under the conditions of Littrow angle incidence
- 1 grade of diffraction efficiency in 1050-1080nm bandwidth range be higher than 99%.The unrelated grating of the polarization that the utility model is proposed
Structure has the characteristics that high incisure density, high-diffraction efficiency, has important application valence in Spectral beam combining and chirped pulse amplification field
Value.
The technical scheme that the utility model is provided is as follows:
A kind of unrelated reflective dielectric grating of polarization based on refractive index regulation film, which is characterized in that the grating packet
Substrate 1 and grating layer 4 are included, and successively plating is formed with reflectance coating 2, oxide dielectric film articulamentum 3 on substrate 1, and in grating layer
Etched diffraction grating slot structure；The reflectance coating 2 is that refractive index regulates and controls dielectric multi-layer optical thin film, which includes high-index material
Film 2-1 and low-index material film 2-2；
The low-refraction Coating Materials of the low-index material film 2-2 is SiO2, the high-index material film
The high-index material of 2-1 is Ta2O5Or HfO2, the material of the oxide dielectric film articulamentum 3 is SiO2。
The substrate 1 is fused quartz substrate, and the grating layer 4 is that refractive index regulates and controls multi-layer dielectric gratings layer.
The reflectance coating 2 and the grating layer 4 are prepared by the method for ion beam sputtering double base spliced target, and material system is
SiO2:Ta2O5Or SiO2:HfO2。
During film layer is coated with, the spatial position between ion source and target is adjusted, realizes high low-refraction in film layer
The mixed proportion of material controls.
Further, the refractive index regulation trend of the reflectance coating 2 is to be incremented by with the etching depth of grating.
The trench structure of the grating layer 4 is rectangular channel or dovetail groove, and screen periods are 1300 lines/mm, and etching depth is small
In 1um, duty cycle range is 0.3~0.7.
The screen periods are not more than 769nm.
The advantageous effects of the utility model are as follows:
1, optical grating construction provided by the utility model be based on refractive index control technique to grating film layer and trench structure into
Row optimization makes the incident light of two kinds of polarization states of TE, TM under the conditions of Littrow angle incidence, and -1 grade of average diffraction efficiency is 1050
It is higher than 99% in~1080nm bandwidth range, and maximum diffraction has been up to 99.8%.
2, prepared by the method that the utility model can use holographic exposure association reaction ion etching, preparation method letter
It is single efficient, it is with important application prospects in high power laser light field.
Detailed description of the invention
Fig. 1 is that the polarization unrelated reflecting medium film optical grating construction provided by the utility model based on refractive index regulation film shows
It is intended to.
Fig. 2 be in the utility model embodiment grating groove profile thin-film refractive index with etching depth change curve.
Fig. 3 is to regulate and control the unrelated grating of polarization of film in 050~1080nm based on refractive index in the utility model embodiment
- 1 grade of diffraction efficiency curve of wave band.
Each appended drawing reference meaning in attached drawing are as follows: 1 fused quartz substrate, 2 refractive index regulate and control dielectric multi-layer optical thin film, 2-1 high refraction
Rate material film, 2-2 low-index material film, 3 sull articulamentums, 4 grating layers.
Specific embodiment
In order to make those skilled in the art more fully understand the technical solution of the utility model, below with reference to the utility model
Attached drawing carries out clear, complete description to the technical solution of the utility model, and based on the embodiment in the application, this field is general
Logical technical staff other similar embodiments obtained without making creative work, all should belong to the application
The range of protection.
As shown in Figure 1, unrelated reflective gratings are polarized for a kind of all dielectric for central wavelength in 1064nm wavelength, it should
Grating is based on refractive index control technique and optimizes to grating film layer and trench structure, makes the incident light of two kinds of polarization states of TE, TM
Under the conditions of Littrow angle incidence, -1 grade of diffraction efficiency is higher than 99% in 1050~1080nm bandwidth range.
The grating includes fused quartz substrate 1 and grating layer 4, and reflectance coating 2, oxidation are successively coated on fused quartz substrate 1
Object deielectric-coating articulamentum 3, and in 4 etched diffraction grating slot structure of grating layer.The reflectance coating 2 is that refractive index regulation multilayer dielectricity is thin
Film successively includes high-index material film 2-1 and low-index material film 2-2 from bottom to up.The grating layer 4 is folding
Penetrate rate regulation multi-layer dielectric gratings layer.
In the optical grating construction, the low-refraction Coating Materials of the low-index material film 2-2 is SiO2, described
The high-index material of high-index material film 2-1 is Ta2O5Or HfO2.The material of the oxide dielectric film articulamentum 3 is
SiO2。
The refractive index regulates and controls dielectric multi-layer optical thin film 2 and the grating layer 4 by the side of ion beam sputtering double base spliced target
Method preparation, material system SiO2:Ta2O5Or SiO2:HfO2, during film layer is coated with, adjust between ion source and target
The mixed proportion control of high low-index material in film layer may be implemented in spatial position.It is built according to Lorentz-Lorentz model
The corresponding relationship of high low-index material mixed proportion and thin-film refractive index is found, thus by adjusting the mixed of high low-index material
The accuracy controlling of thin-film refractive index may be implemented in composition and division in a proportion example.Further, the refraction of the refractive index regulation dielectric multi-layer optical thin film 2
It is to be incremented by with the etching depth of grating that rate, which regulates and controls trend, and each specific refractive index of layer and corresponding thickness are calculated by the optimization specifically used
Method determines.The trench structure of the grating layer is rectangular channel or dovetail groove, and screen periods are 1300 lines/mm, and etching depth is less than
1um, duty cycle range are 0.3~0.7.
After grating initial configuration determines, optical grating construction is carried out using rigorous coupled-wave method combination genetic Optimization Algorithm
Optimization.In one embodiment, based on the trapezoid groove structure in Fig. 1, for TE mode and TM mode in 1030~1080nm wave
Optimization aim of -1 grade of diffraction efficiency of section higher than 99% carries out structure optimization.The design parameter of optical grating construction after optimization are as follows:
Wherein the refractive index of fused quartz substrate 1 is 1.41；
The material of high-index material film 2-1 is Ta in height refractive index cycle reflectance coating 22O5, refractive index 1.91,
With a thickness of 133.2nm；
The material of low-index material film 2-2 is SiO2, refractive index 1.39, with a thickness of 219.6nm；
The material of sull articulamentum 3 is SiO2, refractive index 1.39, with a thickness of 121nm；
The grating groove profile etching depth d=633nm of trapezoidal grating layer 4, groove profile top duty ratio f1=0.35, bottom duty
Than for f2=0.66, the refractive index of period P=769nm, the grating layer are as shown in Figure 3 with etching depth change curve.
Based on the unrelated reflective dielectric grating of the polarization under conditions of 1050~1080 wave bands, incidence angle are 43 degree,
- 1 grade of diffraction efficiency curve of TE polarization mode and TM polarization mode is as shown in Figure 3.As can be seen that provided by the utility model
Polarizing average diffraction efficiency of the unrelated reflective dielectric grating in 1050~1080 wave bands has been more than 99%, and maximum diffraction
It has been up to 99.8%.
Claims (7)
1. a kind of unrelated reflective dielectric grating of polarization based on refractive index regulation film, which is characterized in that the grating includes
Substrate (1) and grating layer (4), and successively plating is formed with reflectance coating (2), oxide dielectric film articulamentum (3) on substrate (1), and
In grating layer etched diffraction grating slot structure；The reflectance coating (2) is that refractive index regulates and controls dielectric multi-layer optical thin film, which includes
High-index material film (2-1) and low-index material film (2-2)；
The low-refraction Coating Materials of the low-index material film (2-2) is SiO2, the high-index material film (2-
1) high-index material is Ta2O5Or HfO2, the material of the oxide dielectric film articulamentum (3) is SiO2。
2. the unrelated reflective dielectric grating of polarization as described in claim 1 based on refractive index regulation film, which is characterized in that
The substrate (1) is fused quartz substrate, and the grating layer (4) is that refractive index regulates and controls multi-layer dielectric gratings layer.
3. the unrelated reflective dielectric grating of polarization as described in claim 1 based on refractive index regulation film, which is characterized in that
The reflectance coating (2) and the grating layer (4) are prepared by the method for ion beam sputtering double base spliced target, and material system is
SiO2:Ta2O5Or SiO2:HfO2。
4. the unrelated reflective dielectric grating of polarization as claimed in claim 3 based on refractive index regulation film, which is characterized in that
During film layer is coated with, the spatial position between ion source and target is adjusted, high low-index material is mixed in realization film layer
The control of composition and division in a proportion example.
5. the unrelated reflective dielectric grating of polarization as claimed in claim 4 based on refractive index regulation film, which is characterized in that
Further, the refractive index regulation trend of the reflectance coating (2) is to be incremented by with the etching depth of grating.
6. the unrelated reflective dielectric grating of polarization as claimed in claim 4 based on refractive index regulation film, which is characterized in that
The trench structure of the grating layer (4) is rectangular channel or dovetail groove, and screen periods are 1300 lines/mm, and etching depth is less than 1um,
Duty cycle range is 0.3~0.7.
7. the unrelated reflective dielectric grating of polarization as claimed in claim 6 based on refractive index regulation film, which is characterized in that
The screen periods are not more than 769nm.
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| CN201820909793.2U CN208672830U (en) | 2018-06-13 | 2018-06-13 | The unrelated reflective dielectric grating of polarization based on refractive index regulation film |
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| CN201820909793.2U CN208672830U (en) | 2018-06-13 | 2018-06-13 | The unrelated reflective dielectric grating of polarization based on refractive index regulation film |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108761610A (en) * | 2018-06-13 | 2018-11-06 | 成都精密光学工程研究中心 | Regulate and control the unrelated reflective dielectric grating of polarization of film based on refractive index |
| CN112946802A (en) * | 2021-02-08 | 2021-06-11 | 暨南大学 | Polarization-independent high-diffraction-efficiency all-dielectric transmission two-dimensional grating |
-
2018
- 2018-06-13 CN CN201820909793.2U patent/CN208672830U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108761610A (en) * | 2018-06-13 | 2018-11-06 | 成都精密光学工程研究中心 | Regulate and control the unrelated reflective dielectric grating of polarization of film based on refractive index |
| CN112946802A (en) * | 2021-02-08 | 2021-06-11 | 暨南大学 | Polarization-independent high-diffraction-efficiency all-dielectric transmission two-dimensional grating |
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Granted publication date: 20190329 Termination date: 20210613 |