Polymer passive Q switch

A study was made of polymer passive Qswitches made of polyurethane acrylate colored with a dithiobenzyl complex of nickel. These switches were designed for the use in YAG:Nd³⁺ lasers. The polymer employed in these switches was elastic in a wide range of temperatures (beginning from –30°C), it adhered well to glass surfaces of the optical grade, and had a high optical strength. The layer structure of these switches improved the transfer of heat from the polymer to the substrate, the thermal conductivity of which was higher, so that the switches could operate stably at radiation intensities up to 16 W/cm² without any need to move the switch. The photochemical stability of the dye in polyurethane acrylate was 10⁶ pulses at a given point. When the resonator length was reduced to 6 cm and the active element was YAG:Nd³⁺ , the duration of the single pulses generated using a passive Q switch of this type was ~0.5 nsec and the divergence did not exceed 1 mrad (the corresponding half-width of the beam in the near-field zone was 1.5 mm).