Development of high-spectral-purity tunable lasers using an auxiliary selected generation

Abstract

We have developed and investigated a simple solution of tunable laser with strongly decreased background emission (max pick-to-pick power ratio ≤ 10-8) by generation at additional wavelengths, except the selected. The cavity scheme permits to obtain easily laser output only at the selected wavelength, using a simple system with interference wedges. The spectral position and the losses at both generations are easily and independently controlled to needed optimal values. The theoretical treatment based on the rate equation system, shows that for the appropriate chosen conditions the technique developed permits to reduce by approximately two orders of magnitude the intensity of the background emission about the selected line (pick power to be less than 10-8). The investigation is on the example of pulsed dye lasers. The results are applicable for other tunable lasers with homogeneously broadened active medium such as Ti:sapphire, diode, etc. The lasers of considered type (with high spectral purity) are of essential interest for application in biomedical investigations of tissue luminescence spectrum, in Raman spectroscopic investigation, in isotope separation.