Abstract

Experimental and theoretical studies have shown that gain gratings in inverted media can exhibit greater-than-unity diffraction efficiency due the stored energy and in four-wave mixing (FWM) can produce very high phase conjugate reflectivities. Such experiments have been performed with laser-pumped Ti:sapphire resulting in reflectivities of nearly 400% at 780nm [1]. It has also been demonstrated that spontaneous gain grating formation can lead to a novel type of laser resonator [2], where the resonator is formed between a conventional mirror and a 'holographic' mirror. The holographic mirror contains the phase information of distortions in the loop and can adapt to cancel out aberrations, as well as provide spectral narrowing.

© 1996 IEEE