Temporal coherence in mirrorless optical parametric oscillators

• One of the unique features of mirrorless optical parametric oscillators based on counterpropagating three-wave interactions is the narrow spectral width of the wave generated in the backward direction. In this work, we investigate experimentally and numerically the influence that a strong phase modulation in the pump has on the spectral bandwidths of the parametric waves and on the efficiency of the nonlinear interaction. The effects of group-velocity mismatch and group-velocity dispersion are elucidated. In particular, it is shown that the substantial increase in temporal coherence of the backward-generated wave can be obtained even for pumping with a temporally incoherent pump. A configuration of a mirrorless optical parametric oscillator is proposed where this gain in spectral coherence is maximized without a penalty in conversion efficiency by employing group-velocity matching of the pump and the forward-generated parametric wave.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

Counterpropagating

Group velocities

Group-velocity mismatch

Incoherent pump

Nonlinear interactions

Parametric waves

Spectral bandwidth

Spectral coherence

Spectral widths

Temporal coherence

Three-wave interactions

Unique features

Conversion efficiency

Phase modulation

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