Eyesafe laser transmitter with brewster angle q-switch in single resonator cavity for both pump laser and optical parametric oscillator

摘要

A laser comprising: a resonator cavity (16) having an optical axis and an outcoupler reflective surface (18) at least one end of the optical axis for at least partially reflecting light of first and second wavelengths within the resonator cavity and for at least partially transmitting light of the second wavelength out from the resonator caity; a pump laser (24) disposed within the resonator cavity and aligned with the optical axis for supplying light at said first wavelength to the laser cavity; an optical parametric oscillator (22) disposed within the resonator cavity and aligned with the optical axis for converting light at said wavelength having a predetermined linear polarization to light of said second wavelength also having said 3040 י' בכסלו התשס" ב - November 25, 2001 predetermined linear polarization, and a saturable absorber Q-switch (26) disposed between the pump laser and the optical parametric oscillator and intersecting said optical axis, wherein the Q-switch has an associated Brewster angle and has a surface aligned at the Brewster angle with respect to the optical axis such that only light having said predetermined linear polarization is transmitted through the Q-switch in a direction parallel to the optical axis; once the light of the first wavelength has reached a predetermined saturation intensity, the Q-switch is substantially transparent to both said first and said second wavelengths, at least when said Q-switch is in its substantially transparent condition, substantially all of the light of the first wavelength that is transmitted aling the optical axis with said predetermined polarization and that has not yet been converted to said second wavelength is reflected back and forth along the entire length of the resonator cavity with said predetermined linear polarization, and substantially all of the light of the second wavelength that is output from the optical oscillator retains said predetermined polarization and is refelected back and forth along the entire length of the resonator cavity until it is eventually transmitted through the partially transmissive outcoupler surface.