J.M. Hendricks

High-phase-conjugate reflectivity (<800%) obtained by degenerate four-wave mixing in a continuous-wave diode-side-pumped Nd:YVO(4) amplifier.

High-phase-conjugate reflectivities of >800% have been achieved through degenerate four-wave mixing in a cw diode-side-pumped Nd:YVO(4) amplifier. Reflectivity curves are shown as a function of input pump-beam intensity for three values of small-signal amplifier gain, and comparison is made with a numerical simulation.

Multiwatt continuous-wave adaptive laser resonator

We present, for what we believe is the first time, results of continuous-wave diode-pumping of a Nd:YVO (4) laser with an adaptive gain-grating resonator. The system is shown to produce more than a 7-W output in a TEM>(00) single longitudinal mode with a laser beam propagation parameter M(2) of <1.3 and <1.1 in the x and y axes, respectively. We demonstrate the self-adaptive abilities of the resonator by spatial correction of an intracavity aberrator for both injected and self-starting versions of the cavity.

Electro-optically controlled beam switching via total internal reflection at a domain-engineered interface in LiNbO3

We report a novel switching method that occurs due to the electro-optic effect under applied field when a beam incident on an interface between anti-parallel domains in a sample of LiNbO3 subtends an angle greater than that required for total internal reflection (TIR). We present data obtained for wavelengths of 0.543 and 1.52µm and compare this with a theoretical model. This switch has many attractive properties, as TIR is a 100% efficient process leading to the possibility of high contrast ratios; current data shows contrast ratios greater than 100:1 (20 dB). Other properties include relatively simple fabrication procedure, low drive voltages and a wavelength dependence that is less than other electro-optic devices such as Pockels cells.

Power scaling of continuous-wave adaptive gain-grating laser resonators

We demonstrate a power-scaling strategy in a continuous-wave adaptive phase-conjugate oscillator power amplifier (PCO-PA) system that actively corrects, via phase-conjugation, for thermally induced phase-distortions introduced by a power-amplifier (PA) placed in the output arm of the phase conjugate oscillator (PCO). Phase-conjugation is achieved by saturable gain four-wave mixing in a PCO Nd:YVO4 amplifier. Single-longitudinal mode phase-conjugate (PC) outputs of almost 11.5 W with an Mx2=1.4, My2=1.2 have so far been achieved with a PCO operating at 6 W PC output, a power gain of two through the PA. The saturable gain four-wave mixing that takes place in the PCO-PA system has been modelled and the results can be used to predict how best to proceed with further increasing the PC output power from such a system.

Non-reciprocal transmission via phase conjugation in multimode optical fibres

Abstract We demonstrate phase conjugate correction of modal distortion of a single mode beam on double-passing a passive highly multimode fibre. Phase conjugation is achieved in a self-pumped photorefractive BaTiO 3 crystal which conjugates only the e-polarised input component. We show that only a small fraction of the multimode fibre output is required to faithfully conjugate the single mode input beam. This technique enables the demonstration of a novel non-reciprocal transmission device, which for example has immediate application in gain-grating holographic resonator designs with multimode fibres as the active gain medium.

Power-scaling continuous-wave adaptive laser resonators

Summary from only given. Self-adaptive gain grating lasers have previously been demonstrated that can actively correct for thermally induced phase distortions. Here we discuss the power-scaling of such a resonator which operates at 6 W in its basic form. Our first attempts using a power amplifier in the output arm have lead to almost 12 W of single longitudinal mode output with a beam quality of M/sup 2/ = 1.3.

Efficient adaptive self-starting Nd:YVO/sub 4/ gain grating laser oscillator

Summary from only given. Self adaptive laser resonators based on laser induced gain gratings have successfully demonstrated correction of thermally induced aberrations in solid-state lasers. This technique has recently been shown to produce distortion corrected beams in a diode pumped, injected seeded system in Nd:YVO/sub 4/. This paper describes the first characterization of a fully self-starting, high power Nd:YVO/sub 4/ self adaptive laser without the requirement of an external seed source.

Multi-watt continuous-wave diode-pumped Nd:YVO/sub 4/ adaptive laser resonator

Summary form only given.Self-adaptive laser resonator architectures based on dynamic gain gratings have been demonstrated to correct for thermally-induced problems in pulse-pumped solid-state lasers. Phase conjugation and efficient gain grating formation have also been demonstrated in a cw amplifier. In this paper we present, for the first time to our knowledge, operation of a self-adaptive diode-pumped solid-state laser system capable of producing high-power cw laser radiation with good beam quality. Both an injected and a self-starting version of the system will be presented.

Distortion-correcting holographic resonators

High phase conjugate reflectivities (R > 10,000%) have been achieved through degenerate four-wave mixing in a cw diode-side-pumped Nd:YVO4 amplifier and the interactions have been successfully modelled. This four-wave mixing geometry has subsequently been used in the design of a phase-conjugate resonator operating with a single- longitudinal mode TEMoo near-diffraction limited output of > 7 W, which is capable of correcting for severe intra-cavity phase distortions.

High-reflectivity continuous-wave phase conjugation by four-wave mixing in a diode-pumped Nd:YVO/sub 4/ amplifier

Summary form only given. Self-adaptive laser resonators formed by diffraction from a gain grating have shown considerable promise for correction of distortions in high average power laser systems as well as for spectral and temporal control of the laser radiation. We have shown that high gain and high diffraction efficiency gain gratings are possible in a continuous-wave mode of operation from a diode-pumped solid-state (DPSS) laser amplifier, and this is the first such demonstration of a continuous-wave diode pumped solid-state (DPSS) laser amplifier as a four-wave mixing medium. This result is of considerable importance since it now makes possible the operation of continuous-wave self-adaptive solid-state lasers and the compensation of thermal lensing when operating at high powers.