Ultimate-fast all-optical switching of a microcavity

In this thesis we study ultrafast all-optical switching of microcavities. We employ the electronic Kerr effect to switch the resonance frequency of microcavities operating at telecom wavelengths. We observe the fastest possible switching of a microcavity resonance within 300 fs. The switching speed is only determined by the cavity storage time; only limited by the speed of light and not by material related relaxation properties. For the first time, we derive and measure the non-degenerate three-photon absorption coefficient of GaAs. Using the measured nondegenerate two- and three-photon absorption coefficients we estimate that the trigger laser only lose 22 aJ/µm2 at each switch event, which is a record level of minimum energy loss per switch event. We achieve repeated switching of microcavities within 700 fs, corresponding to THz rates. Therefore to best of our knowledge, we have broken the THz clock rate barrier experimentally using semiconductor cavities for the first time. The THz clock rate that we achieve can be a solution for information technology that is exploring ways to meet the growth rate of the computational demand. The color of light is a main visual perception of light for humans. Indeed, a simple measure for the color of light is given by its frequency since frequency of light is invariant from one medium to another. Although the propagation of light is strongly modified using nanostructures such as photonic crystals and microcavities, the frequency of light stays constant in these structures as well. The color of light can be changed in a nonlinear process or by absorption and re-emission. Using microcavities light is conveniently confined in space and then by dynamical control the medium can be changed to act as a nonlinear medium for light. Remarkably, we show that during the switching of cavities we achieve both up and down frequency conversion of light. The frequency conversion that we observe is a result of the instantaneous refractive index change achieved using the electronic Kerr effect. We achieve repeated frequency conversion at THz rates and generate blue- and red-shifted light pulses at this rate.