Progress in research on neodymium doped strontium aluminate lanthanum magnesium laser crystals by Shanghai Optics and Machinery Institute

Recently, the Advanced Laser and Optoelectronic Functional Materials Department of the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, has made progress in the research of Nd: ASL (Sr0.7Nd0.05La0.25Mg0.3Al22.7O19) laser crystals, and the related achievements were published in Infrared Physics&Technology under the title of "Tunable laser operations on Nd doped continuum and lanthanum aluminum crystals".

Neodymium (Nd3+) ion is one of the common activating ions, and its absorption peak matches the emission wavelength of commercial laser diodes (LDs), with high absorption efficiency at 0.9, 1.05, and 1.35 μ There are emission peaks at position m, and laser emission has been achieved in various matrix materials. Nd: ASL is a typical disordered crystal, belonging to the hexagonal crystal system. The high disorder leads to its spectral broadening, which is beneficial for generating lasers of different wavelengths.

In order to investigate its tuning characteristics, the research team grew Nd: ASL crystals with a doping concentration of 5%, and measured their fluorescence lifetime to be approximately 371.8 μ S. At 1.05 μ Near m, its fluorescence spectrum has four strong and continuous emission spectra. A birefringent filter was inserted into the V-shaped resonant cavity for tunable laser experiments. By using output mirrors with transmittance of 5%, 7%, and 10%, three independent wavelengths (1050, 1062, and 1074 nm) of laser output were obtained. The wavelength range is 1049.59-1054.43 nm and 1059.71-1078.18 nm for tuning, with a tuning width greater than 20 nm, which is consistent with the spectrum. The phenomenon of multi wavelength laser output was also observed in the experiment. The results indicate that Nd: ASL crystals are a gain medium suitable for tunable lasers. Compared with single wavelength laser media, controlling and changing the wavelength is much more convenient and suitable for complex application scenarios with higher accuracy or more wavelengths.

This work has received support from projects such as the National Natural Science Foundation of China.

Figure 1. Fluorescence spectrum of Nd: ASL crystal

Figure 2. Laser output with three wavelengths at different output mirror transmittance

Figure 3. Output power at different wavelengths under the same absorption pump power

Source: Shanghai Institute of Optics and Mechanics