Pierre Sillard

Gain-grating analysis of a self-starting self-pumped phase-conjugate Nd:YAG loop resonator

We investigate both experimentally and theoretically the contribution of the different gain gratings in a self-starting self-pumped phase-conjugate Nd:YAG loop resonator. Thanks to a transient model, we show that the transmission-grating configuration is more efficient than the reflection-grating configuration, and that their temporal dynamics are different, in agreement with the experiment. Maximum extraction is obtained for the four-grating configuration. The output beam is a high-quality diffraction-limited TEM/sub 00/ mode, even with severe intracavity phase aberrations, and has a single-longitudinal-mode pulse shape of /spl sim/13 ns, with maximum energy of /spl sim/130 mJ up to 30 Hz. We also investigate the role of the output coupler reflectivity on the output pulse energy and formation. Finally, the influence of the different gratings on the ability of such a self-starting loop resonator to correct for polarization distorsions is studied.

Self-pumped phase-conjugate diode-pumped Nd:YAG loop resonator

We demonstrate a self-pumped phase-conjugate diode-pumped Nd:YAG loop resonator. In the injected configuration a maximum phase-conjugate reflectivity of 32 is obtained. The output beam has a pulse shape of ~30 ns , which shows the self- Q -switching ability of the resonator. By use of a low-refractive-output coupler, a self-starting version was produced. The resonator operated in a stable diffraction-limited TEM(00) mode, even with severe intracavity phase aberrations. A maximum energy of 5.5 mJ (2.4% of the energy of the high-brightness stacks that was incident upon the Nd:YAG crystals) in a 20-ns single-longitudinal-mode pulse was measured.

Nd:YAG loop resonator with a Cr/sup 4+/:YAG self-pumped phase-conjugate mirror

We demonstrate a Nd:YAG loop resonator with a self-pumped phase conjugate, mirror in a Cr/sup 4+/:YAG crystal, in the nanosecond regime. A maximum extraction of 29 mJ and a maximum reflectivity of 3.3 are obtained. The output beam is a high-quality diffraction-limited TEM/sub 00/ mode and has a pulse shape of /spl sim/20-ns duration, showing the self Q-switching ability of the resonator. In addition, we demonstrate an original and specific configuration of the anisotropic Cr/sup 4+/:YAG crystal that compensates not only for phase aberrations but also for polarization aberrations induced into the loop resonator.

Self-pumped phase-conjugate resonator with two-pass four-wave mixing in a diode-pumped Nd:YAG amplifier

We investigate both theoretically and experimentally a self-pumped phase-conjugate resonator with two-pass four-wave mixing in a diode-pumped Nd:YAG amplifier. A transient model is presented to fit the energy and temporal results of the experiment. The influence of the input energy in the injected configuration and the influence of the output coupler reflectivity and diode pump energy in the self-starting configuration are analyzed. In the injected case a maximum phase-conjugate reflectivity of 32 is obtained. In the self-starting case a TEM00 mode of 5.5 mJ in a 20-ns single-longitudinal-mode pulse is produced with a 10% reflectivity output coupler.

In-line Nd:YAG resonator using self-pumped phase conjugation in Cr(4+):YAG.

We report the operation of an in-line Nd:YAG resonator using self-pumped phase conjugation in Cr(4+): YAG at lambda=1.064microm in the nanosecond regime. The output beam has a high-quality diffraction-limited TEM(00) mode and a pulse shape of ~15ns , showing the self- Q -switching ability of the resonator. A maximum extraction of 18mJ and a maximum reflectivity of 2.0 are measured. A transient model provides insight into the energy characteristics and the dynamics of such an in-line resonator.

Self-pumped phase-conjugate resonators with four-wave mixing in diode-pumped amplifiers

Experimental and theoretical investigations of self-pumped phase-conjugate (SPPC) resonators with four-wave mixing (FWM) in diode-pumped amplifiers are presented. A model that uses a transient treatment of FWM (in one-pass or two-pass geometries) allows us to analyze the temporal dynamics and the energy characteristics of these resonators in both injected and self-starting configurations. The influence of the input energy in the injected case, and the influence of the output coupler reflectivity and diode pump energy in the self-starting case are analyzed. In the self-starting case, the SPPC resonators demonstrate self-adaptive compensation of phase distortions and produce a TEM00 mode in a single-longitudinal-mode pulse by dynamic gain-grating formation with a reasonable optical-optical efficiency.

Self-pumped phase-conjugate loop resonators using four-wave mixing in solid state gain media

Self-pumped phase-conjugate (SPPC) loop resonators using four-wave mixing (FWM) in solid-state gain media are investigated in both injected and self-starting configurations. A model, using a transient treatment of FWM with the appropriate boundary conditions imposed by the loop geometry, allows us to analyze the threshold condition for oscillation, the temporal dynamics and the energy characteristics of such resonators. The influence of the input energy in the injected configuration, and the influence of the different gain gratings and output coupler reflectivity in the self-starting configuration are also analyzed. A SPPC loop resonator using FWM in a flash-lamp- pumped Nd:YAG amplifier is experimentally investigated. In the injected case, a maximum phase-conjugate reflectivity of 42, and a maximum extraction of 47 mJ are obtained. In the self-starting case, a TEM00 mode output of approximately 130 mJ in a 13 ns single-longitudinal-mode pulse is produced up to 30 Hz. Experimental and theoretical results are in good agreement.