Simulation and Analysis of a High Power Diode-End-Pumped Nd:YVO4 Solid- State Laser

Abstract
Nd:YVO4 is widely and commercially available laser material for diode-pumped lasers. Compared
to Nd:YAG, Nd:YVO4 has a larger stimulated emission cross-section, larger absorption coefficient and
broader absorption bandwidth. It has lower threshold and its output power is less sensitive to the
drifting of the diode pump wavelength. In this paper a Nd:YVO4 crystal at 1064nm pumped with a high
power diode laser at 808nm is modeled and simulated using LasCAD software tool package. These
models investigate the optimum cavity design parameters (length of the cavity, output coupler
reflectivity, the beam overlap key parameter and crystal dimensions). The geometry of the cavity is
optimized to produce maximum TEM00 laser output, taking into consideration the thermal gradient on
the rod structure. The cavity optimum configuration neglecting the insignificant effect of changing rod
length was; 66mm in length, 90% of output coupler reflectivity. The pumping beam spot size affects
on the laser output and the final optical conversion efficiency. Controlling the pumped spot size ( ) to
be equal the mode spot size ( ) the maximum beam overlap efficiency and consequently the
maximum optical slope efficiency with the highest laser output were achieved. The Nd:YVO4 Crystal
with dimension of (1-3mm) diameter and (7-10mm) length with 1% doping concentration (1at.%) is
the suitable choice for the DEPSS (Diode End Pumped Solid State ) laser configuration. A final optical
conversion efficiency of 52% and a maximum slope efficiency of 54% were obtained. These results
can be improved by rescaling the transfer efficiency to become around 90%.