Chromium-doped magnesium calcium silicate tunable laser crystal and preparation method thereof

Abstract

The invention provides a chromium-doped calcium magnesium silicate tunable laser crystal and a preparation method thereof. The crystal has a molecular formula of Cr<3+>:CaMgSi2O6. The crustal belongs to a monoclinic system, and a space group of C12 / c1. Cell parameters of the crystal are that a=9.741 angstrom, b=8.901 angstrom, c=5.257 angstrom, beta=105.97 DEG, V=439.1 angstrom<3>, Z=4, and Dc=3.271 g / cm3. Cr<3+>:CaMgSi2O6 is a same-composition molten compound. High-optical-quality and large-size crystals can be grown with a Czochralski method. Growth conditions comprise that: a growth temperature is 1500 DEG, a pulling speed is 0.2-0.8mm / h, and a crystal rotation speed is 10-20rpm. A tunable range is 700-1350nm. The crystal is possible to become a novel tunable laser crystal, and can be practically applied.

Description

technical field [0001] The invention relates to the technical field of optoelectronic functional materials, in particular to a laser crystal material used as a working substance in a tunable solid-state laser. Background technique [0002] Tunable laser refers to such an effect: the pump excites the active ions doped in the solid-state laser matrix to generate laser light, using prism tuning method, F-P etalon tuning method, grating tuning method, filter tuning method and distributed feedback System tuning method, etc. to obtain tunable laser output. [0003] In 1963, L.F. Johnson and others used flash lamp pumping, doped with Ni 2+ MgF 2 The first solid-state tunable laser operation was realized in a crystal (L.F. Johnson R.E. Dietz & H.J. Guggenheim, J. Phys. Rev. Lett., 11(1963) 318). Subsequently, many tunable laser crystals appeared, such as Ti 3+ :Al 2 o 3 、Cr 3+ :Mg 2 SiO 4 、Cr 3+ :LiSrAlF 6 and Cr 3+ :BeAl 2 o 4 etc., but due to various reasons, many tu...

AI Technical Summary

Problems solved by technology

Subsequently, many tunable laser crystals appeared, such as Ti 3+ :Al 2 o 3 、Cr 3+ :Mg 2 SiO 4 、Cr 3+ :LiSrAlF 6 and Cr 3+ :BeAl 2 o 4 etc., but due to various reasons, many tunable laser crystals are limited to laboratory tools and cannot be promoted to industrial applications

The tunable laser crystal that has been studied the most and has entered the application field is Cr 3+ :BeAl 2 o 4 (Alexandrite), Ti 3+ :Al 2 o 3 (titanium-doped sapphire), Cr 3+ :LiCaAlF 6 and Cr 3+ :LiSrAlF 6 , but they also have some unavoidable defects that limit their application range

[0004] Cr 3+ :BeAl 2 o 4 The main disadvantages of (Alexandrite) crystals are: the tuning range is between 700 and 800nm, and the emission cross section is small (6×10 -21 cm 2 ), the required pumping threshold is high, and it also has the disadvantages of high damage rate and high thermal lens effect. In addition, because BeO is highly toxic, it also brings great difficulties to growth.

[0005] Ti 3+ :Al 2 o 3 The main disadvantage of the crystal is: the Ti in the crystal 3+ - Ti 4+ The appearance of ion pairs causes absorption in the laser output band, that is, the near-infrared band, which affects its laser performance, and because of its short lifetime of the upper energy level of the laser (only 3.2μs), it is necessary to use short pulse lasers, Q-switched lasers, continuous Pumping with a wave laser or a flash lamp that produces particularly short pulses further limits its applications.

However, there are also problems such as small absorption coefficient and low laser efficiency of LD pumping.