Parametric down-conversion luminescence: a fertile ground in quantum optics

Radek Machulka, Karel Lemr, Ondřej Haderka +3 more

Single-photon sources based on the process of spontaneous parametric down-conversion play a key role in various applied disciplines of quantum optics. We characterize intrinsic luminescence of BBO crystals as a source of non-removable noise in quantum-optics experiments. By analysing its spectral and temporal properties together with its intensity, we evaluate the impact of luminescence on single-photon state preparation using spontaneous parametric down-conversion.

T. B. Pittman, B. C. Jacobs, J. D. Franson

Ramarao Inguva

Geraldo Alexandre Barbosa

An optical device that utilizes a semiconductor switch and parametric luminescence from a non-inversion symmetric crystal is proposed to generate a light beam with sub-Poissonian number variance. Numerical estimates based on a simplified model indicate qualitative features of the optical switch and the signal intensity achieving sub-Poissonian variance. The calculation is exemplified with parameters from a GaAs–AlGaAs multiple-quantum well structure (MQW) within a Fabri-Perot cavity. Conjugated beams (for example, λ 1 =8322 Å and λ 2 =8230 Å) from the down-conversion luminescence in a KDP crystal are selected by a pinhole system and directed to the MQW. Non-linear refractive index changes are induced by fluctuations in the pump beam (λ 2 ) matched to an excitonic level ( N =1) of the bi-dimensional GaAs and modulates the cavity compensating for identical fluctuations in the signal beam (λ 1 ).

Yen-Ju Chen, Chun-Yuan Cheng, Tien-Dat Pham +4 more

Quantum fluctuation plays a key role in the parametric down-conversion in the Langevin regime. In this paper, we report the experimental realization of optical parametric down-conversion in the Langevin regime on a chip. By precisely controlling the loss inherently tied to fluctuation, we observe the asymmetric Hong-Ou-Mandel dip - a hallmark of quantum fluctuation in the fluctuation-driven PDC, and the fluctuation-induced compression of single photons by nearly one order of magnitude. These findings pave the way for the manipulation of quantum fluctuation, quantum states, and system-reservoir interaction.

Klaus M. Gheri, Daniel F. Walls