Dye Laser Action by Two-Photon Excitation

Since dye lasers are very widely tunable from near ultra-violet to near infrared, they have been used in high resolution spectroscopy and many other tunable laser applications. Usually, dye lasers are pumped by onephoton excitation process with shorter wavelength light source compared with laser output wavelength. In this paper, we propose a new excitation method of dye by two-photon process, and also would like to report a numerical calculation of two-photon absorption cross section, as well as a demonstration of laser oscillation by two-photon excitation.