Self-pumped phase conjugation in cerium-doped barium titanate crystal using nanosecond pulses from a laser diode (original) (raw)
Related papers
Laser-diode self-pumped phase conjugation in cerium-doped barium titanate crystal
Optik, 2001
The performance of laser-diode (LD) self-pumped phase-conjugation (SPPC) using cerium-doped barium titanate (Ce:BaTiO 3 ) crystal was investigated. The reflectivity of the phase conjugator against the incident angle and the incident position was measured in two configurations, and the reflectivity could reach as high as 74%. According to the optical path patterns appearing in the crystal, it is believed that the LD-SPPC in Ce:BaTiO 3 is established by a stimulated photorefractive backscattering and four-wave mixing mechanism.
Self-pumped phase conjugation with nanosecond pulses in strontium barium niobate
Optics Letters, 1990
We report the observation of self-pumped phase conjugation by means of internal reflection in a photorefractive medium produced by a series of intense nanosecond pulses. Nanosecond pulses from a YAG laser ranging in intensity from 9 X 104 to 9 X 105 W/cm 2 were used. The crystal was rhodium-doped strontium barium niobate.
Time response of a cerium-doped Sr_075Ba_025Nb_2O_6 self-pumped phase-conjugate mirror
Optics Letters, 1987
Self-pumping in cerium-doped strontium barium niobate has been observed with phase-conjugate reflectivities near 6% and a formation time of 8 sec for a 200-mW/cm 2 beam at 442 nm. The time response for asymmetrical selfdefocusing was also measured, and the observed transmissions through the crystal at normal incidence were limited to about 1.5% of the incident radiation.
Mutually pumped phase conjugation in photorefractive strontium barium niobate: theory and experiment
Journal of the Optical Society of America B, 1990
Two mutually incoherent laser beams can generate each other's phase-conjugate replica by sharing holograms in a photorefractive strontium barium niobate (SBN) crystal. The path of each beam inside the SBN crystal uses three internal reflections at the crystal faces. We discuss phase-conjugate imaging, moving gratings induced by an applied electric field, the time response of grating formation, and the dependence of the phaseconjugate reflectivity on the incident-beam ratio. Also, we derive the amplitude coupled-wave solutions for mutually pumped phase conjugators with two coupled gratings, and we compare the theoretical results with our experimental results.
Phase conjugation by stimulated photorefractive scattering using a retroreflected seeding beam
Journal of the Optical Society of America B, 1992
The threshold for self-pumped optical phase conjugation by means of backward stimulated photorefractive scattering has been dramatically lowered by inserting a retroreflecting screen into the path of the beam after the beam leaves a BaTiO 3 crystal. Stable ref lectivities of as much as -60% and good phase-conjugate fidelity have been demonstrated in a crystal that has too low a gain-length product to exhibit unseeded backward stimulated scattering. Precise control of the threshold for stimulated scattering is demonstrated by adjusting the seed intensity. Reflectivity and fidelity are experimentally characterized at 515 nm as a function of the following parameters: pump and seed intensities, crystal angle with respect to the incident beam direction, crystal interaction length, crystal-lens separation, and aberration strength. Operation at 633, 730-800, and 839 nm is demonstrated also. 0740-3224/92/091726-09$05.00
Enhancement of the switched phase conjugate reflectivity in a BaTiO3 crystal
Optical Materials, 2004
We experimentally investigated the response of the photorefractive phase conjugation to a pulsed reading beam in an undoped BaTiO 3 crystal with a four-wave mixing geometry. A single longitudinal-mode Ar þ laser was used as a light source. The reading beam with a pulse width of $1 s was switched on after writing a steady-state grating in the crystal by two recording beams under a suitable condition and the generated phase conjugation was measured. The phase conjugate output was found to be increased by some factors of magnitude over the initial value for a given peak power and period of the reading pulses. A maximum of the enhanced reflectivity can be controlled by adjusting the interacting beam powers. An increase in the diffraction efficiency was also found with the same read-out process, which plays a key role to increase the phase conjugation as our knowledge.
Comparison between continuous-wave and pulsed photorefraction in barium titanate
1994
A numerical model of photorefraction in barium titanate with simultaneous hole and electron photoconductivity and combined deep and secondary photorefractive centers is compared with experimental observations of both continuous-wave (10 mW/cm 2-20 W/cm 2) and pulsed high-peak-intensity (1-40 MW/cm 2) laser illumination. Between 10 mW/cm 2 and 20 W/cm 2 (continuous wave) and below-10 MW/cm 2 (pulsed) the sample is hole dominated and has a sublinear intensity-dependent response time, whereas above-12 MW/cm 2 (pulsed) the crystal displays dominant electron conductivity and has a superlinear intensity-dependent response time.
Applied Optics, 1998
Self-pumped phase conjugation in infrared-sensitive photorefractive rhodium-doped barium titanate ͑Rh:BaTiO 3 ͒ is investigated with a kilohertz-repetition-rate, diode-pumped Nd:YAG laser. We also demonstrate the operation of a diode-pumped Nd:YAG master-oscillator power-amplifier system with such a compact and solid-state phase-conjugate mirror for wave-front restoration. We obtain neardiffraction-limited output pulses of 20-mJ energy at a repetition rate of 200 Hz and a 1-min response time of the phase-conjugate mirror. The performances of the Rh:BaTiO 3 crystal are compared with those obtained with a conventional Brillouin mirror.
Self-pumped phase conjugation in photorefractive crystals: Reflectivity and spatial fidelity
Physical Review A, 1997
A two-dimensional model for the self-pumped phase conjugation in photorefractive crystals is presented. Numerical simulations of the beam path for beam fanning and the self-pumped phase conjugation within the crystals show good agreement with the experimental observations. We numerically study the dependence of the self-pumped phase conjugation reflectivity and spatial fidelity on the incident angle, the position of the incident beam upon the input face, and the input wavelength, which are in good agreement with the published and our experimental results. ͓S1050-2947͑97͒09103-8͔