Integrated quantum optics

Nondegenerate two-photon absorption in GaAs/AlGaAs multiple quantum well waveguides

We present femtosecond pump-probe measurements of the nondegenerate (1960nm excitation and 1176–1326nm probe) two-photon absorption spectra quantum well waveguides. Experiments were performed with light pulses copolarized normal and tangential to the quantum well plane. The results are compared to perturbative calculations of transition rates between states determined by the k.p method with an 8- or 14-band basis. We find excellent agreement between theory and experiment for normal polarization, then use the model to support predictions of orders-of-magnitude enhancement of nondegenerate two-photon absorption as one constituent photon energy nears an intersubband resonance.

N. Cox, J. Wei, H. Pattanaik, T. Tabbakh, S.-P. Gorza, D. Hagan, and E. W. Van Stryland, Phys. Rev. Research 2, 013376 (2020). DOI

Integrated quantum optics

Strong Nonlinear Coupling in a Si3N4 Ring Resonator

We report a nonlinear strong coupling between to weak fields containing a few photons inside a cavity. This strong coupling is the result of an effective second order nonlinearity induced by strong pump field in a Kerr cavity. The strong coupling regime is evidenced by Rabi splitting of the cavity resonance.

REFERENCE: Ramelow, S, Farsi, A, Verno, Z, S. Clemmen, Ji, X, Sipe, J, Liscidini, M, Lipson, M, Gaeta, A, Strong Nonlinear Coupling in a Si3N4 Ring Resonator, Physical Review Letters, 122, p.153906 (2019) DOI