Optical parametric oscillator

Patent Pending An optical parametric oscillator (OPO) is a parametric oscillator that oscillates at optical frequencies. It converts an input laser wave (called "pump") with frequency \omega_p into two output waves of lower frequency (\omega_s, \omega_i) by means of second-order nonlinear optical interaction. The sum of the output waves' frequencies is equal to the input wave frequency: \omega_s + \omega_i=\omega_p. For historic reasons, the two output waves are called "signal" and "idler", where the output wave with higher frequency is called signal. A special case is the degenerate OPO, when the output frequency is one-half the pump frequency, \omega_s=\omega_i=\omega_p/2.