Quasiresonant excitation of InP/InGaP quantum dots using second harmonic generated in a photonic crystal cavity.

Indistinguishable single photons are necessary for quantum information processing applications. Resonant or quasiresonant excitation of single quantum dots provides greater single photon indistinguishability than incoherent pumping, but is also more challenging experimentally. Here, we demonstrate high signal to noise quasiresonant excitation of InP/InGaP quantum dots. The excitation is provided via second harmonic generated from a telecommunications wavelength laser resonant with the fundamental mode of a photonic crystal cavity, fabricated at twice the quantum dot transition wavelength. The second harmonic is generated using the χ⁽²⁾ nonlinearity of the InGaP material matrix. [ABSTRACT FROM AUTHOR]