Fourth-harmonic generation of a continuous-wave CO_2 laser by use of an AgGaSe_2/ZnGeP_2 doubly resonant device

Abstract

We report a doubly resonant continuous-wave CO(2) laser frequency-quadrupling device that generates 200nW of 2.55-mum (4?) and as much as 2mW of 5.1-mum (2?) radiation out of 1.7-W fundamental radiation at 10.2 mum (?). The quadrupling process results from two resonant cascading second-harmonic generations by use of a walk-off-compensated twin AgGaSe(2) device (??2?) and a ZnGeP(2)nonlinear crystal (2??4?).

Optical, vibrational, thermal, electrical, damage, and phase-matching properties of lithium thioindate

“…The performance of devices based on mid-IR chalcogenides is often limited by deleterious thermal effects (lensing, expansion) [4,7,24]. The thermal figure of merit of a material can be defined by the quantity η = (dn/dT )/K where dn/dT is the thermo-optic index variation and K is the thermal conductivity.…”

“…The thermally-related properties of a new nonlinear material are crucial in assessing its potential in real nonlinear conversion devices pumped by high power cw or pulsed lasers. The performance of devices based on mid-IR chalcogenides is often limited by deleterious thermal effects (lensing, expansion) [4,7,24]. The thermal figure of merit of a material can be defined by the quantity η = (dn/dT )/K where dn/dT is the thermo-optic index variation and K is the thermal conductivity.…”

“…ZGP has a high nonlinearity (72 pm/V) and thermal conductivity but requires pump wavelength above 2 µm due to its residual absorption in the near-IR. The noble metal compounds (AGS, AGSe) have the lowest residual absorption, but their poor thermal conductivity due to lowenergy phonon spectrum limits their performance, especially in cw applications [4,5,6,7]. Furthermore, their thermal expansion is anisotropic along the direction parallel and perpendicular to the optic axis, which is a source of thermo-mechanical stresses.…”

Solid state molecular sensor for detection of chemical and biological agents

“…In this case, integration is less important, and the key technological task is the development of high-intensity lasers operating at wavelengths in the mid-(3 − 5µm) and far-IR (8 − 12µm). [2][3][4][5][6] The limitations imposed by the transparency windows of the earth's atmosphere in such high power applications do not apply to the highly-localized SSMS systems, which generally provides for a wider range of detection.…”