Ultimate fast optical switching of a planar microcavity in the telecom wavelength range

Applied Physics Letters (Impact Factor: 3.52). 02/2011; 98. DOI: 10.1063/1.3580615
Source: arXiv

ABSTRACT We have studied a GaAs-AlAs planar microcavity with a resonance near 1300 nm
in the telecom range by ultrafast pump-probe reflectivity. By the judicious
choice of pump frequency, we observe a ultimate fast and reversible decrease of
the resonance frequency by more than half a linewidth due to the instantaneous
electronic Kerr eff?ect. The switch-on and switch-off? of the cavity is only
limited by the cavity storage time of ?tcav = 0.3ps and not by intrinsic
material parameters. Our results pave the way to supra-THz switching rates for
on-chip data modulation and real-time cavity quantum electrodynamics.

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    ABSTRACT: We have performed ultrafast pump–probe experiments on a GaAs–AlAs microcavity with a resonance near 1300 nm in the "Original" telecom band. We concentrate on ultimate-fast optical switching of the cavity resonance that is measured as a function of pump-pulse energy. We observe that, at low pump-pulse energies, the switching of the cavity resonance is governed by the instantaneous electronic Kerr effect and is achieved within 300 fs. At high pump-pulse energies, the index change induced by free carriers generated in the GaAs start to compete with the electronic Kerr effect and reduce the resonance frequency shift. We have developed an analytic model that pre-dicts this competition in agreement with the experimental data. To this end, we derive the nondegenerate two-and three-photon absorption coefficients for GaAs. Our model includes a new term in the intensity-dependent refractive index that considers the effect of the probe-pulse intensity, which is resonantly enhanced by the cavity. We calculate the effect of the resonantly enhanced probe light on the refractive index change induced by the electronic Kerr effect for cavities with different quality factors. By exploiting the linear regime where only the electronic Kerr effect is observed, we manage to retrieve the nondegenerate third-order nonlinear susceptibility χ …3† for GaAs from the cavity resonance shift as a function of pump-pulse energy.
    Journal of the Optical Society of America B 01/2012; 29(9):2630-2642. · 2.21 Impact Factor

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