Laser with an adaptive loop cavity

A laser with an adaptive loop cavity is proposed. During the growth of lasing an additional phase-conjugate cavity, representing a loop system with parametric feedback, is formed. It is reported that a single-mode neodymium laser with an adaptive loop cavity has been built. It operates on the basis of frequency-degenerate four-wave mixing in a Cr⁴⁺ : YSGG crystal. It is shown that the additional phase-conjugate cavity can influence significantly the lasing efficiency.