A kind of photothermographic refraction mid-infrared glass and its preparation method

Abstract

The invention discloses a photothermographic refraction mid-infrared glass and a preparation method thereof, which are made of the following molar percentage raw materials: GeO 2 60%~79.97%, A 2 o 3 5%~10%, MO 5%~18%, MF 2 5%~10%, NF 5%~10%, MnF 2 0.02%~0.1%, Ag 2 O 0.01%-0.1%; wherein, A is Al or Ga element; M is Ba or Zn element; N is Li, Na or K element. The preparation method includes: preparing a glass mixture with compounds as raw materials; putting the glass mixture into a platinum crucible with a cover, putting it into an electric furnace to heat up to 1200-1400°C and keeping it warm for 1-3 hours for melting; The liquid is poured into a copper mold and cooled to form glass, and the formed glass is kept at 460-500°C for 2-6 hours for annealing treatment, and finally cooled to room temperature at a rate of 0.2-1°C / min. The photothermographic refraction mid-infrared glass of the present invention has a relatively high transmittance (>80%) in the 3-4.5 μm band, and can form a refractive index modulation degree up to 0.002 inside the glass through laser irradiation and heat treatment, which can be used in Fabrication of high-performance mid-infrared volume Bragg gratings.

Description

technical field [0001] The invention belongs to the field of infrared glass materials, and relates to a photothermographic refraction glass, in particular to a photothermographic refraction mid-infrared glass and a preparation method thereof. Background technique [0002] Volume Bragg gratings are the core components of various advanced optoelectronic equipment, which are generally obtained by exposing and heat-treating photothermographic glass to form a periodic refractive index distribution inside the glass. Volume Bragg gratings play a very important role in improving laser beam quality, realizing petawatt pulse compression and stretching, angle-selective near-field filtering, semiconductor laser output spectrum stabilization, and mode selection. At the same time, due to its high diffraction efficiency and easy integration, volume Bragg gratings can meet the requirements of high efficiency, compactness, stability and low cost of advanced beam analysis separation and contr...

AI Technical Summary

Problems solved by technology

In 2004, Zhao Quanzhong and others from Shanghai Institute of Optics and Mechanics worked in CaF 2 A volume grating is prepared in an infrared crystal, but its refractive index modulation amplitude is only 0.000357, resulting in extremely low diffraction efficiency of the grating

In 2013, MacLachlan et al. of Heriot-Watt University in the United Kingdom obtained a mid-infrared volume grating in Ga-La-S chalcogenide glass by using 1064 nanometer femtosecond laser etching technology. Through calculation and simulation, it was found that the refractive index modulation amplitude was 0.0075, and at 2640 The first-order diffraction efficiency in the nanometer mid-infrared band is 24%, but it is difficult to prepare large-scale volume gratings using this technology

However, the above-mentioned mid-infrared materials all have their own unavoidable shortcomings, such as crystal materials (CaF 2 , ZnSe, etc.) can obtain a small degree of refractive index modulation, it is difficult to meet the requirements of diffraction efficiency, and it is impossible to use the mature two-beam interference method to prepare volume Bragg gratings; the photosensitive stability of chalcogenide glass is poor, such as photodarkening easily Or photobleaching and other phenomena, poor work stability

At present, there are no reports of photothermorefractive materials with high refractive index modulation and high work stability that can work in the 3-5 μm band.

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