“Fast” amplifying optical Kerr gate using stimulated emission of organic non-linear dyes

Abstract

We describe a “fast” optical Kerr gate (OKG) which can act at the same time as light amplifier. As a Kerr medium we used different laser dyes (Cresyl violet, Nile blue, Rhodamine 640). The most efficient at available wavelengths (595 nm and 297 nm) was Cresyl violet dissolved in methanol. With a classical OKG arrangement we obtained a maximum transmission of 4000% at 650 nm (strong amplification of the tramsmitted signal), this wavelength corresponding to a gain maximum of Cresyl violet. The opening time of the OKG was 15 ps limited by the reorientation time of the dye molecule in methanol solvent. With a special OKG arrangement based on the use of two delayed opening pulses, we obtained 240% transmission at the same wavelength with an opening time of 2.5 ps. Possible improvements of the method are described.