MIR and NIR nonlinear optical processing using intersubband χ(3) in triple quantum well structures

Abstract

We have calculated the resonant and nonresonant third-order nonlinearity χ(3) for third harmonic generation (THG) and four wave mixing (FWM) in two triple quantum well structures. The first structure is designed to access both THG (χ(3)(3ω)) and FWM (χ(3)(ω4)) at mid-infrared wavelengths in a single device. It is found that χ(3)(3ω) = 1.8 × 10−14 (m V−1)2 at a wavelength near 9.6 µm and χ(3)(ω4) = 1.5 × 10−14 (m V−1)2 at 3.8 µm. In the second structure near infrared FWM and nonresonant THG can be obtained using strain-compensated InGaAs-InAlAs material. In the latter structure χ(3)(ω4) exhibits a peak as a function of biasing corresponding to the energy levels being made equally spaced due to the triply resonant four wave mixing phenomenon. Also, it has been shown that high conversion efficiency can be obtained at the above condition. A nonresonant χ(3)(3ω) of 1.6 × 10−15 (m V−1)2 is calculated at 5 µm and shown to have appreciable values at near infrared wavelengths for increased bias.