INVESTIGATION OF SPECTRAL BLEACHING IN PASSIVE Q-SWITCH DYES

Abstract

The bleaching characteristics of saturable dyes have been studied by varying the spectral width of a Q‐switched ruby laser. Recent reports of mode selection properties of dyes used as passive Q switches and of absorption spectra of dyes while in the bleached state have been interpreted in terms of narrow spectral saturation (``hole‐burning''). This view implies that certain dyes have inhomogeneously broadened absorption bands consisting of relatively narrow components. Our results indicate that the lower limit to the width of these components for cryptocyanine is ∼1 cm⁻¹.