Efficient passive laser Q-switches based on dye-doped polyurethane for high-energy neodymium lasers

This paper studies energy and time operation characteristics of a laser on a Nd3+:YAG crystal with passive Q-switches based on a dye-activated aliphatic polyurethane matrix with high radiation strength. A high efficiency of laser generation both in a free mode and at single pulse generation in the Q-switched regime is obtained using a samarium diffuse reflector with a BaSO4 filler. A single pulse energy and duration for the lasers with passive Q-switches based on organo-nickel complex BDN and polymethine dye IR-1061 in an aliphatic polyurethane matrix polymerized by the polycondensation method from 1.6-diisocyanatohexane, poly[di(ethylene glycol) adipate] and trimethylolpropane as starting components were compared. A powerful single pulse with an energy of ~1 J was obtained in the Q-switching mode using polymethine thiopyrylo-4-tricarbocyanine dye (IR-1061). The highly efficient Q-switching caused by the use of passive laser Q-switch based on the IR-1061 dye is shown to be due to its specific linear and nonlinear spectral properties.