Abstract

A laser-like emission from powders of solid state luminophosphors was reported in a number of publications, see for example Refs. [1,2]. A dramatic narrowing of Nd emission line (⁴F_3/2-⁴I_11/2) in powders of Nd doped laser materials is observed when the pumping energy exceeds some critical threshold value. At the same time, a series of short (0.3-1 ns) 1.06 μm emission pulses appears in response to 10-30 ns pumping pulse. In the present paper we report second harmonic generation in a powder laser based on a mixture of Nd_0.5La_0.5Al₃(BO₃)₄ and 2-methyl-4-nitroaniline (MNA). We excited the powders with 10 ns laser pulses at 580 nm. The pumping beam was focused to 0.02 cm² spot. Under intense pumping, short pulses (typical for Nd powder lasers) were obtained at 1.06 μm in the mixtures of powders and in pure Nd_0.5La_0.5Al₃(BO₃)₄. Simultaneously, 0.53 μm second harmonic radiation was observed in mixed samples. The slope of the dependence of 0.53 μm light intensity, I_0.53, on 1.06 μm light intensity, I_1.06, [Ln(I_0.53) vs Ln(I_1.06)] is equal to 2. We have shown that the threshold of the powder laser stimulated emission increases and the slope efficiency decreases with the increase of MNA concentration in the mixture, Fig. 1.

© 1998 IEEE