We have measured as a function of incident angle, for a range of critical angles between 880° and 89° and of characteristic gain depths between 41 and 96 probe wavelengths, the single-pass reflectance of a He–Ne probe beam reflected from a transverse optically pumped solution of rhodamine B. In contrast to previously reported experiments, no anomalously high reflectances were observed. The theoretical formulas for the exponentially nonuniform- gain model reproduce well the observed reflectance curves including the locations, slopes, and heights of the amplification maximum in the vicinity of critical angle. Peak amplifications of 200–300% were predicted and observed for the given experimental conditions.
© 1983 Optical Society of AmericaPDF Article