Self-pumped Phase Conjugation Reflectivity Research Articles

Preparation and photorefractive properties of barium strontium titanate (Ba 1−xSr xTiO 3)

Single crystals of Ba 1− x Sr x TiO 3 with 0.015 ⩽ x ⩽ 0.05 have been grown by Czochralski technique. The optical transmission spectrum and the photorefractive experimental results of a single-domain Ba 0.952Sr 0.048TiO 3 sample are reported. The effective density of empty traps N E, a lumped parameter n 3 o r eff and the response time at the total optical intensity of 1 W/cm 2 were measured by two-beam coupling experiments to be 4.7 × 10 16cm -3, 190 pm/V and 0.8 s, respectively. Self-pumped phase conjugation has been observed at nine wavelengths ranging from 457.9 nm to 632.8 nm. Self-pumped phase-conjugate reflectivities higher than 35% were obtained for all of the wavelengths used. The highest value is 55% reached at 514.5 nm.

High-reflectivity self-pumped phase conjugator using total internal reflection in KNbNO3:Fe

A self-pumped phase conjugate reflectivity of 74.8% is obtained with a suitably cut KNbO3:Fe crystal in a polygonal shape. The design and operation of this self-pumped phase conjugator is described. The build-up time is observed to be dependent on the input power. The phase conjugate nature of the retroreflected beam has been further confirmed by a significant decrease in the specular reflectivity of the input surface of the crystal.

Self-pumped and double phase conjugation in GaAs with applied dc electric field

Self-pumped and double phase conjugation are first demonstrated in undoped GaAs with applied dc electric field at 1.06 μm wavelength. Phase-conjugate reflectivities of up to 3% and 0.5% respectively, are obtained and other dependences are reported. Reported values of the self-pumped phase-conjugate reflectivity are compared with those of InP.

Self-pumped optical phase conjugation and light oscillation in Fe doped KNbO 3

We report different experiments on self-pumped phase conjugation in iron doped KNbO 3 crystals at room temperature. Self-pumped phase conjugate reflectivities of a linear cavity, an external ring mirror and a configuration where no external optical elements are required have been measured. Using the passive ring resonator a reflectivity of 30% of a self-pumped phase conjugate mirror has been measured at room temperature. In the configuration requiring no external optical elements besides the KNbO 3 crystal a reflectivity of 12% has been measured. In degenerate four-wave mixing phase conjugate reflectivities of up to 270% have been observed in the diffusion recording mode.

Control of self-pumped phase-conjugate reflectivity using incoherent erasure

We use an incoherent erase beam to control optical chaos and to increase the phase-conjugate reflectivity in a self-pumped phase-conjugate mirror. Focused and large-area incoherent illumination was used to modify or eliminate selected gratings in the crystal.

Optical feedback, wavelength response, and interference effects of self-pumped phase conjugation in BaTiO_3

It is shown that even slight optical feedback of a self-pumped phase-conjugate signal into dye or argon-ion lasers causes laser wavelength and conjugator reflectivity changes. The wavelength dependence of the self-pumped phase-conjugate reflectivity in barium titanate is examined over most of the visible spectrum. It is also demonstrated that interference between two collinear beams incident upon the conjugator affects the behavior of the phase-conjugate mirror.