Narrow-band tunable optical parametric oscillator with beam-splitter

摘要

The bandwidth of the generated radiation is reduced by a wavelength-selective prism (T) and Littrow or Littmann grating (C) outside the resonator, which is constituted by the mirrors (M3, M4) on either side of the nonlinear optical crystal (C). The beam-splitter (DM1) diverts part (2) of the pumping pulse (1) through a delay line (D) to a dichroic mirror (DM2) which reflects it into the resonator. Broadband radiation is sepd. by a spatial filter (RM) consisting e.g. of two wedge plates in mirror-image relationship. The amplified narrowband radiation is emitted (3) through an iris (B).