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Metal reflective immersion grating and optical system with low polarization and high diffraction efficiency

A diffraction efficiency and metal reflection technology, applied in the field of gratings, can solve the problems of polarization degree and diffraction efficiency grating groove tolerance, and achieve the effect of reducing the difficulty of manufacturing process, low polarization, and reducing groove density

Active Publication Date: 2020-11-17
SUZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, for a metal reflective immersion grating with high groove density at a large angle of incidence, the groove shape of the grating can only achieve low polarization and high diffraction efficiency if the grating groove shape meets the conditions of large duty cycle and high depth period ratio, and at this time the degree of polarization and diffraction efficiency are affected by The groove tolerance of the grating has a great influence, which poses a great challenge to the manufacturing process of the grating

Method used

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  • Metal reflective immersion grating and optical system with low polarization and high diffraction efficiency
  • Metal reflective immersion grating and optical system with low polarization and high diffraction efficiency
  • Metal reflective immersion grating and optical system with low polarization and high diffraction efficiency

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Embodiment 1

[0054] The material of the grating layer 3 is fused silica optical glass, and the material of the dielectric layer 4 is TiO 2 , the metal reflection layer 5 is silver, the period d of the grating layer 3 is 690 nanometers, the groove depth of the grating layer 3 and the period ratio h are 0.8, the duty ratio f of the grating layer 3 is 0.3, and the duty ratio of the metal reflection layer 5 is t is 0.37. The incident angle θ of the incident light in the grating layer 3 is 47°.

[0055] see figure 2 Shown is the variation curve of the average diffraction efficiency at the central wavelength of the working band with the thickness a of the dielectric layer 4 . image 3 is the variation curve of the relative degree of linear polarization DP at the central wavelength of the working band with the thickness a of the dielectric layer 4; figure 2 and image 3 It can be seen that when the thickness a of the dielectric layer is 115 nm, the immersion grating has better diffraction e...

Embodiment 2

[0058] The material of the grating layer 3 is fused silica optical glass, and the dielectric layer 4 is Al 2 o 3 , the metal reflective layer 5 is silver, the period d of the grating layer 3 is 690 nanometers, the groove depth to period ratio h of the grating layer 3 is 0.8, and the duty cycle t of the metal reflective layer 5 is 0.2. The incident angle θ of the incident light in the grating layer 3 is 48°.

[0059] Figure 5 It is the variation trend of the average diffraction efficiency at the central wavelength of the working band with the thickness a of the dielectric layer 4 and the duty cycle f of the grating layer 3 in embodiment two; Fig. 6 is the relative linear polarization DP at the central wavelength of the working band with the medium The variation trend of the thickness a of the layer 4 and the duty ratio f of the grating layer 3, the colors in the figure indicate the average diffraction efficiency and the relative linear polarization degree. combine Figure ...

Embodiment 3

[0062] The material of the grating layer 3 is fused silica optical glass, and the dielectric layer 4 is TiO 2 , the metal reflection layer 5 is silver, the period d of the grating layer 3 is 1010 nanometers, the ratio h of the groove depth to the period of the grating layer 3 is 0.8, and the duty ratio t of the metal reflection layer 5 is 0.4. The incident angle θ of the incident light in the grating layer 3 is 43°.

[0063] Fig. 8 is the variation trend of the average diffraction efficiency at the central wavelength of the working band with the thickness a of the dielectric layer 4 and the duty cycle f of the grating layer 3 in embodiment three; the relative degree of linear polarization DP at the central wavelength of Fig. 9 varies with the dielectric layer The variation trend of the thickness a of 4 and the duty ratio f of the grating layer 3, the colors in the figure indicate the average diffraction efficiency and the relative degree of linear polarization. combine Figu...

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Abstract

The invention discloses a metal reflective immersion grating with low polarization and high diffraction efficiency and an optical system, comprising: a grating layer, the grating layer includes a plurality of first grooves arranged in an array; The thickness of the dielectric layer is less than the groove depth of the grating layer, and the surface of the dielectric layer forms a second groove; the metal reflective layer is located on the side of the dielectric layer away from the grating layer, and the side of the metal reflective layer fills the second groove; the grating layer The first interface is formed between the medium layer and the medium layer, and the second interface is formed between the medium layer and the metal reflective layer; the incident light enters the direction of the first interface through the interior of the grating layer, and passes through the first interface, the medium layer and the metal reflective layer. A diffraction effect occurs between the second interfaces to generate diffracted light, which is reflected by the metal reflective layer and exits from the inside of the grating layer. It can realize low polarization and high diffraction efficiency, reduce the difficulty of manufacturing process, and has important application value in the field of high-resolution atmospheric detection.

Description

technical field [0001] The invention relates to the technical field of gratings, in particular to a metal reflective immersion grating with low polarization and high diffraction efficiency and an optical system. Background technique [0002] In grating-type hyperspectral imaging instruments, especially for spectrometers used to detect atmospheric components, the grating with the characteristics of low polarization, high diffraction efficiency, and high dispersion is one of the core components for the instrument to achieve high-precision detection and inversion. As the spectral resolution requirements of the instrument increase, the volume and mass of the system increase dramatically. E. Hulthén proposed the concept of immersion grating (see E. Hulthén, and H. Neuhaus, Nature, 1954, 173(4401):442-443.), when the grating surface is immersed in a medium with a refractive index n, its spectrum The resolving power is increased by n times than that without immersion. This means ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02B5/18
CPCG02B5/1861
Inventor 潘俏沈为民
Owner SUZHOU UNIV