Abstract

Simple low background emission (≤ 10⁻⁶) wideband tunable (~100 nm) narrowline (~10-20 pm) dye and Ti:Al₂O₃ lasers are developed. They employ our original selective cavity (Fig.l) in which a single high thickness (~100µm) interferometer (interference wedge - IW or a piezopushing Fabry-Perot - FPI) selects a single narrow line [1]. The laser axes cross the interferometer at two appropriate angles θ₁ and θ₂ and thus only a single coincidence of resonances can occur for both sequences of resonant orders corresponding to θ₁ and θ₂ respectively in the region of ~ 100 nm and higher. The tuning of the coinciding resonances can be obtained by the IW translation or by the FPI piezopushing. Along with simplicity and the use of a single interferometer, the configuration in Fig.l presents two natural advantages by which the proposed cavity differs from the traditionally used selective schemes: i) absence of the non-selective reinjection of the emitted light for both outputs of the active medium; ii) for a single round-trip the light crosses the interferometer four times which increases essentially the contrast of the selection. The noted differences are the base for a high spectral purity narrowline emission.

© 1996 IEEE