P. N. Ilinykh

Phase shift in nondegenerate coupling of waves in the photorefractive crystal

Abstract The phase between the interference pattern and the photorefractive holographic grating and also between the signal beam intensity oscillations and the external ac field applied to the crystal have been investigated under coupling of the two waves with different frequency.

Nondegenerate photorefractive four-wave mixing without feedback in Bi12TiO20

Abstract A new scheme of four-wave mixing is proposed and experimentally realized in a photorefractive crystal Bi 12 TiO 20 . Copropagating signal and pump waves have a frequency difference Ω and record static grating in an ac external field with the same frequency Ω. Counterpropagating waves have equal frequencies and do not record gratings in an external ac field. The theory is developed in the undepleted pump approximation.

Photorefractive hologram recording by beams with frequency difference multiple to that of external AC field

The mechanism of the recording of a static hologram by a rapidly moving interference pattern in a photorefractive crystal is investigated theoretically and experimentally. The difference between the frequencies of the writing beams strongly exceeds the inverse response time of the hologram and is equal or multiple to the frequency of the external ac field applied to the crystal. The experiment was performed in Bi12TiO20 crystal.

Higher spatial harmonics of photorefractive gratings written by phase-locked detection

The higher spatial harmonics of the photorefractive response have been studied theoretically and experimentally for gratings written by phase-locked detection in an alternating external field. The conditions for writing higher spatial harmonics are derived analytically. The amplitude of the second spatial harmonic has been found experimentally as a function of the spatial frequency in two Bi12TiO20 crystals.

Recording of higher spatial harmonics of a photorefractive grating through the phase-locked detection mechanism

Abstract The peculiarities of higher harmonics in the photorefractive response are considered theoretically for a grating recorded through the mechanism of phase-locked detection by an external ac field. The conditions for higher harmonic grating recording is found analytically. The dependence of second spatial harmonics on spatial frequency is measured in two different samples of Bi 12 TiO 20 .