ABSTRACT
We report, for the first time to our knowledge, on picosecondpulse optical phase conjugation using photorefractive Sn(2)P(2)S(6) crystals. For 7.2-ps pulses at 1.06 mum, we have achieved phase-conjugate reflectivities of up to 45% with very fast build-up times, about 15 ms at an intensity of 23 W/cm(2) using Te-doped Sn(2)P(2)S(6). We furthermore demonstrate aberration-free 5 W optical output of 8-ps pulses at 1.06 mum from a side pumped Nd:YVO(4) amplifier using the Sn(2)P(2)S(6)-based phase-conjugate feedback.
Subject(s)
Amplifiers, Electronic , Lasers , Optical Devices , Refractometry/instrumentation , Signal Processing, Computer-Assisted/instrumentation , Equipment Design , Equipment Failure AnalysisABSTRACT
We demonstrate double phase-conjugation in pure and Te-doped Sn(2)P(2)S(6), a semiconducting ferroelectric material, at the wavelength of 685 nm. We observe a phase conjugate reflectivity of more than 800% at an intensity ratio of the pump beams of 44 for Te-doped Sn(2)P(2)S(6). Using a laser diode bar emitting at 685 nm, we demonstrate double phase conjugation of three independent emitters of the laser diode bar with a single mode master laser. By adjusting the center wavelength of the master laser to the center wavelength of an emitter with an accuracy of less than 0.1 nm, locking of any emitter of the laser diode bar is demonstrated. We improve the spectral width of the emitter from 0.5 nm to below 2.5 x 10(-4) nm.
ABSTRACT
We demonstrated for what is the first time to our knowledge photorefractive two-wave mixing in a bulk ferroelectric crystal using cw light at the telecommunication wavelength 1.55 microm. In the Te-doped ferroelectric semiconductor Sn2P2S6 with absorption constant <0.1 cm(-1) at 1.55 microm, grating recording times of 10 ms and a two-beam coupling gain of 2.8 cm(-1) have been measured at 350 mW power (intensity 440 W/cm(2)) without a necessity to apply an external electric field. With a moving grating technique, a maximal gain of 6.0 cm(-1) has been obtained.
ABSTRACT
We demonstrate self-pumped optical phase conjugation in Te-doped Sn2P2S6, a semiconducting ferroelectric crystal, using a 1.06 microm wavelength cw Nd:YAG laser. The photorefractive gain of this crystal has been increased to Gamma = (3.9+/- 0.4) cm-1 by Te doping. We observed self-pumped optical phase conjugation in a ring cavity scheme with phase conjugate reflectivities of more than 40 percent and a very fast phase conjugate rise time below 100ms at a light intensity of 20 W/cm2. This is more than two orders of magnitude faster than in any other photorefractive crystal, as e.g. in Rh-doped BaTiO3.
