Second-harmonic generation of a tunable continuous-wave CO_2laser in orientation-patterned GaAs

Abstract

Tunable, mid-infrared radiation was obtained by frequency doubling of a continuous-wave CO(2) laser in orientation-patterned GaAs crystal. Active cooling of the crystal minimized pump-induced thermal effects, allowing generation of output powers exceeding 300 mW across the wavelength range of 4.63-4.78 μm.

Coupling-length phase matching for nonlinear optical frequency conversion in parallel waveguides

“…(14) [ξ DF (z) of Eq. (20)] tending to the propagation distance z multiplied by the values given in the third and fifth columns. The quantities η SF max and η DF max give the maximum photon-conversion efficiencies in the depleted regime for each CLPM condition.…”

“…The black dotted curve in (c) corresponds to the analytical solution in the undepleted regime according to Eqs. (19) and (20). For these plotsà ≡ |A (a) 3,0 A (a) 2,0 | 1/2 , kL = κ 1 L = 200, κ 2 L = κ 3 L = 60, and Ldà = 2.…”

“…As an example we mention gallium arsenide (GaAs), which has a large nonlinearity and a wide transparency range, making it very attractive for mid-IR coherent sources (e.g., with generated wavelengths in the atmospheric transmission windows). While relevant efforts to engineer quasi-phasematching in GaAs have been ongoing-starting from diffusion bonding of periodically orientation-reversed thin wafers [15] and more recently followed by directly grown orientationpatterned crystals [16][17][18][19][20]-the use of the CLPM processes discussed in this work represents a valid alternative that can be easily realized by simply creating two parallel waveguides using well-established methods. CLPM would then enable, e.g., difference-frequency generation between wavelengths of 1.5 and 2.1 μm to deliver radiation near 5.25 μm, while a source at ∼10 μm could be built by difference-frequency generation between 2.5 μm and 2 μm.…”

Mixing of polarization states in zincblende nonlinear optical crystals

“…Epitaxial methods of growing crystals with periodically alternating domain orientations have been developed in GaAs [2–4] and GaP [5, 6]. These quasi-phasematched zincblende materials have been used to demonstrate second-harmonic generation (SHG) [7–9], optical parametric oscillation [10–15], difference frequency generation (DFG) [16–20] and optical parametric generation [21].…”

CO2 laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements

“…The harmful effect on SHG efficiency in OP-GaAs due to high average power was also observed by Guha and coworkers. 23 They were able to mitigate these effects by using more aggressive active cooling than was used in the present work, with heat removal provided by a thermoelectric cooler rather than a fan. As a consequence, they generated 300 mW of cw power at the second-harmonic wavelength of 4.8 μm with an input power of 30 W at the fundamental wavelength of 9.6 μm.…”