Characteristics of optical filters built on the basis of periodic relief reflective structures

Vladislav A Komotskii,Valeriya D Evstigneeva,Jose Pauyac Huaman

doi:10.22363/2658-4670-2019-27-2-143-153

Vladislav A Komotskii, Valeriya D Evstigneeva + Show 1 more

Open Access

https://doi.org/10.22363/2658-4670-2019-27-2-143-153

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Abstract

A scheme of a new type optical filter, built using a relief reflective periodic diffraction structure, which has a specific rectangular profile, is proposed. The input radiation beam is directed to the relief structure at a certain angle of incidence. The zero diffraction order beam is our output beam, which is separated from the other diffraction order beams with the help of a diaphragm. The incidence-reflection plane is parallel to the relief lines of the diffraction structure. The dependence of the output beam power on the angle of incidence and on the wavelength of the radiation is investigated. It is shown that the power transfer coefficient from the input to the output of the scheme substantially depends on the wavelength of the optical beam. The scheme can be used as an optical signal filter. The spectral characteristic of this type of filter has an oscillating character. The zero (minimum) values of the power transfer coefficient of radiation from the input to the output of the filter alternate with maximum values close to unity. The spectral characteristic of the filter is easy to change by changing the angle of incidence of the input beam to the relief reflecting structure. Filters of this type can be built for the ultraviolet, visible, and infrared range. Calculations of the dependence of the filter parameters on the relief depth and on the angle of incidence of the input optical beam to the relief structure are presented.

Highlights

We consider the spectral characteristics of optical filters of a new type [5], which are constructed using relief reflective structures (RRS) with a rectangular profile, with “square wave” form, whose protrusion length is equal to depression length
L is the distance from the RRS to the diaphragm, D is the diameter of the optical beam, Λ is the period of the diffraction structure, the number p is the safety factor, which is necessary to prevent penetration of the radiation beams of the first orders of diffraction into the aperture of the diaphragm
Filters based on RRS have a number of positive properties

Summary

Introduction

The need of filtering optical radiation appears in the conduction of physical experiments and in solving technical problems, in which it is necessary to separate a useful signal with specific wavelength from the background radiation. Dependence of the transfer coefficient on the radiation wavelength λ, angle of incidence θ, and RRS depth Hg for zero diffraction order, can be expressed by the formula: kp. When the corner reflector is rotated, the position of the point of incidence on the RRS remains unchanged, and the reflection point at the mirror moves, and at certain angles of rotation it may go out from the mirror limits, and as a consequence the scheme would stop working.the scheme shown in Figure 2 has smaller range of possibilities for changing the spectral characteristics of the filter compared with the first scheme (Figure 1)

Estimated characteristics of filters based on RRS

Conclusion