Jean-Jacques Zondy

We analyze the dynamics, two-mode squeezing as well as Einstein–Podolsky–Rozen (EPR) correlations of the signal–idler beams in a cavity with two resonant cascaded nonlinear crystals. The subharmonic system is trifurcated and self-phase-locked, and enables the existence of stable steady bright-beam/dark-beam solutions, leading to different properties of squeezing and EPR correlations. Compared with conventional nondegenerate optical parametric oscillators, our results can be helpful to quantum information processing as well metrology.

We report on the first BaGa₄Se₇ nanosecond optical parametric oscillator pumped by Q-switched Nd:YLiF₄ laser at 1053nm. Mid-infrared idler wave tuning from 2.2 mm to 10.4 mm is demonstrated with an angle-tuned type-I (o-ee) y-cut sample.

We report on the first characterization of orientation-patterned gallium phosphide (OP-GaP) crystals used to generate narrow-linewidth, coherent mid-infrared (MIR) radiation at 5.85 μm by difference frequency generation (DFG) of continuous-wave (cw) Nd:YAG laser at 1064nm and diode-laser at 1301nm. By comparison of the experimental absolute MIR efficiency versus focusing to Gaussian beam DFG theory, we derive an effective nonlinear coefficient for first-order quasi-phase-matched OP-GaP at the generated DFG wavelength. Using d = (2/π)d ₁₄ and taking into account Miller's delta rule, we retrieve an absolute value of the d ₁₄ quadratic nonlinear susceptibility coefficient of GaP of d ₁₄ = 27.2(3) pm/V at 5.85 μm, in good agreement with the latest absolute measurement of this nonlinear coefficient from non-phase-matched second-harmonic generation (1.32 μm → 0.66 μm) taking into account multiple reflection effects [Shoji et al 1997 J. Opt. Soc. Am. B 14 2268]. The temperature and signal-wave tuning curves are also in qualitative agreement with a recently proposed temperature-dependent Sellmeier equation for OP-GaP when focusing effects are taken into account.

Optical parametric oscillation is demonstrated for the first time with the chalcogenide nonlinear crystal LiGaSe ₂ pumped by a nanosecond Nd:YAG laser. Angle tuning provides coverage of the 4.8–9.9 µ m spectral range in the mid-IR by idler pulses.

Linestrengths, and nitrogen-collision-induced broadening and pressure shift coefficients of methane’s ν3-band singlet lines near 3.3μm have been measured from direct absorption spectroscopy using a tunable cw OPO spectrometer.