ABSTRACT
Dye lasers and optical parametric oscillators offer alternative means of obtaining tunable, coherent radiation throughout the near infrared, visible and near ultraviolet regions of the spectrum. Until recently dye lasers fulfilled this role more satisfactorily, particularly in the visible region of the spectrum, and the use of parametric oscillators was more or less confined to regions of the spectrum inaccessible to dye lasers, such as the near infrared. This chapter considers the use of an etalon with an optical thickness of 9 mm and a finesse of 20. The resonator geometries may be regarded as the conventional geometries for the line narrowing of dye lasers. Optical parametric oscillation is a process which depends critically on the temporal and spatial coherence of the pump laser. This is not the case in dye lasers where the creation of a real population inversion in the gain medium decouples the generation process for the coherent radiation from the properties of the pump radiation.
