掺Er^(3+)玻璃的光限幅特性研究

Optical Limiting Response in Er^(3+)-Doped TeO_2-Nb_2O_5-ZnO Glass

利用波长为532 nm的皮秒脉冲激光,研究了掺Er3+玻璃的光限幅特性和反饱和吸收。当入射功率不断增加且超过一定阈值时,透射功率不再随着入射功率快速增大,而是逐渐趋向于较稳定状态,从而实现了对强激光的光限幅效应。进一步利用布居速率方程讨论了其机制并给出了激发态的吸收截面,结果表明激发态吸收是其主要的光限幅机理。

Nonlinear optical properties of Er^3＋ doped heavy metal telluride glass were studied by picosecond laser pulses. The optical limiting response was measured by a transmission technique, and the reverse saturable absorption （RSA） by a Z-scan technique, When the incident power reached the threshold, the tranmitted power did not grow rapidly with the incident power as before, but remained almost constant. It means that the Er^3＋-doped glass possesses an optical limiting effect. The experimental resuits show that the excited absorption is responsible for the measured RSA, resulting in optical limiting response. The measured data can be well simulated by a rate equation model to obtain the absorption cross sections of the excited state.