Recently, the research group of Hu Lili from the Department of Advanced Laser and Optoelectronic Functional Materials, Shanghai Institute of Optics and Precision Machinery, Chinese Academy of Sciences (SIPM, CAS), has proposed a new scheme based on the use of Dy3+ doped quartz glass as a yellow light laser material. ray induced darkening in Dy-doped silica glasses at visible wavelengths" published in the Journal of the American Ceramic Society.
Currently, yellow laser light from Dy3+ doped materials has important potential applications in the fields of Bose-Einstein condensation and photocoagulation therapy. Fluoride fiber matrices are widely used as the main material of visible gain fibers due to their low phonon distribution. However, fluoride optical fibers have limitations such as poor chemical stability and mechanical properties, and harsh preparation conditions, which substantially increase the cost and difficulty of preparation. In contrast, quartz glass matrix has gained rapid development due to the advantages of excellent physical, chemical and mechanical properties and good optical performance, and has successfully realized the yellow laser output of Dy3+ ions. However, Dy3+-doped quartz fibers have the problem of photon darkening under the excitation of blue light, which limits the further improvement of the output power. Therefore, how to inhibit photon darkening has become a key scientific problem in the field of visible light lasers.
The research team proposes a new solution for Dy3+-doped quartz glass to resist photon darkening. By increasing the P/Al ratio, the scheme inhibits the formation of defects such as Dy ion valorization and Al-OHC from within the glass matrix, thus dramatically reducing the irradiation-induced absorption loss. In quartz glass, Al is a commonly used dispersant for rare earth ions, which can improve the dispersion and solubility of rare earth ions. However, due to the mismatch between the valence state of Al3+ in quartz glass and the matrix Si, defects such as the cavity center Al-OHC are easily generated after absorbing a certain amount of energy (blue light, ultraviolet irradiation). The introduction of P is able to form valence-balanced and stable [PAlO4] structural groups with Al, which inhibits the formation of Al-related defects and thus improves the light-darkening resistance of Dy-doped quartz glass. This work provides key material and method support for visible fiber lasers.
The research was supported by the National Natural Science Foundation of China and other programs.
Fig. 1 Elevated P/Al ratio suppresses irradiation-induced defects in quartz glass
