Simultaneous multiple wavelength CW operation of LD pumped composite Nd:(YAG,YLF) laser rod

Abstract

Simultaneous lasing at multiple wavelength of solid-state lasers has been reported by a number of researchers, which may be used in double wavelength lidar, nonlinear optical study and laser medical treatment. One way to achieve multiple wavelength lasing is through utilizing the different energy levels of the active ion. Another way is by doping more that one active ions into one single host crystal. In addition, combining different laser crystals together should also be able to achieve multiple wavelength lasing and may provide a broader flexibility in choosing different wavelength combinations. One thing should be noticed is that the absorption spectrum of lasers with multiple active ions or multiple host materials will become a multiple absorption spectrum. This will be a problem when using laser diodes (LD) as a pumping source because of the narrow bandwidth of LD emission which can only match well with one absorption peak. We used two of the frequently used laser crystals: Nd/sup 3+/ doped YAG and YLF and mounted them together using two bonding methods within a single cavity. By using a LD pumping source which is a off-resonant absorption or wind-pumping system, we achieved simultaneous CW output at wavelength of 1064 nm and 1047 nm, among which output at wavelength of 1047 nm is about 25 % out of the total 30 W under 150 W LD input power. Different bonding methods are compared which shows that the use of a simple optical adhesive is effective at low and middle power presenting no deterioration.