parametric oscillator [¦par·ǝ¦me·trik `äs·ǝ´lād·ǝr] ELECTRONICS An oscillator in which the reactance parameter of an energy-storage device is varied to obtain oscillation. OPTICS A device consisting of an optically nonlinear crystal surrounded by a pair of mirrors to which is applied a relatively high-frequency laser beam and a relatively low-frequency signal, resulting in a low-frequency output whose frequency can be varied, usually by varying the indices of refraction. |