Highly efficient passive Q switches for a neodymium laser based on thiopyrylotricarbocyanine dyes

The spectral, photochemical and nonlinear optical properties of a group of thiopyrylotricarbocyanine dyes in a polyurethane matrix are studied and compared with well-known materials for passive Q-switching such as nickel BDN and BDNII complexes. Passive laser Q switches based on these dyes feature the high modulation efficiency (up to 76%) in neodymium lasers and high photochemical stability. It is shown that the service life of Q switches can be considerably increased by removing oxygen from a polymer matrix.