Laser saturation grating phenomena

Vladilen S Letokhov, V. P. Chebotaev

V V Tumorin, Nikolai N Il'ichev

The production of the temperature grating of the refractive-index variation upon recording a gain grating in solid laser media is considered. The dependence between the amplitudes of the temperature grating and saturated-gain grating is found. Based on the dependence obtained, the phase component of the inverse-population grating in a Nd:YAlO 3 crystal is determined.

V. M. Kenkre

B. Jaskorzyńska, Evgeny V. Vanin, Sten Helmfrid

Gain-saturation gratings, induced by the interaction between the active medium and standing waves in laser cavities, influence the performance of lasers. The modulation depth of the grating is reduced by diffusion of the excitation energy in most host materials, but gain saturation has been modeled only in the limit of strong or weak diffusion. We present an analytical solution of the diffusion equation for two-level systems at an arbitrary diffusion rate. It is shown that for many rare-earth dopants the migration process is not well described by either the weak- or the strong-diffusion approximation.

V. I. Lvov, A. A. Stepanov, Vladimir A. Shcheglov

D. D. Krylova, G. Kramer

Two new schemes for achieving optical Ramsey resonance by use of gratings are suggested. They do not need a coincidence of the gratings’ period with the laser wavelength and permit the same gratings to be used for arbitrary optical transition. A theoretical description for the Gaussian shapes of laser beams and for arbitrary saturation is given.