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Two-photon absorption is a third-order process and, as such, displays a quadratic dependence relatively to the incident light intensity. This TPA process has been harnessed in a new generation of ultrafast light intensity correlator setups [1,2]. This quadratic dependence of the photocurrent to the sub-bandgap light intensity has been checked in various semiconductor-based devices, and verified over...
The second-order coherence properties of highly-incoherent cw sources (true blackbody and amplified spontaneous emission) are directly evidenced at femtosecond timescales by use of an interferometric autocorrelator based on a two-photon absorption in a GaAs phototube.
Detection at optical communication wavelength is achieved, for the first time, in GaAs phototube by non degenerate two-photon absorption. Signal photon is supported by a pump field, producing a quantum ldquoleg uprdquo effect.
We show that a guided-wave approach to Fresnel phase-matching is relevant even for thick semiconductor wafers. This approach is implemented to design a bulk GaAs optical parametric oscillator and a terahertz generator by difference-frequency generation.
We describe the concept of fractional quasi-phasematching which is shown to provide efficient nonlinear conversion, close to perfectly phasematched scenarios. The conceptual design in the case of second-harmonic generation is presented, along with predicted performances.
We present a new quasiphase matching scenario based on the Fresnel birefringence occurring at total internal reflection, Thanks to non resonant conditions on the semiconductor plate thickness, ultrawide tunability is made possible (8-13 /spl mu/m).
Tunable midinfrared sources (8-12 /spl mu/m) based on GaAs and ZnSe slabs are presented. Quasi-phase matched difference frequency generation is obtained by total internal reflection. In nanosecond operation, we get up to 0.5 nanojoule of midinfrared light.
Summary form only given. Second-harmonic susceptibility of asymmetric or electrically biased GaAs/AlGaAs quantum wells (QWs) can be exploited to realize frequency-conversion devices in the near-infrared. The calculated /spl xi//sup (2/) values associated with interband transitions are in the range of 10-20 pm/V. In this paper we have measured the /spl xi//sup (2/) in biased symmetric QWs, where the...
Summary form only given. Large nonlinear coefficient, possibility of integration with semiconductor lasers, and excellent control of structures make GaAs waveguides very well suited to nonlinear frequency conversion in the near-infrared. Realization of GaAs waveguide converters has been prevented until now by the problem of phase matching. Phase matching can be achieved by use of artificial birefringence...
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