Azimuthal eigenmodes at strongly non-degenerate parametric down-conversion

Abstract

Quantum-optical technologies based on the effect of parametric light downconversion are not yet applied in the terahertz frequency range. This is owing to the absence of terahertz single-photon detectors and the strong entanglement of modes of optical-terahertz biphotons. This study investigates the angular structure of scattered radiation generated by strongly non-degenerate parametric down-conversion. It demonstrates that under certain approximations, it is possible to obtain azimuthal eigenmodes for the nonlinear-interaction operator. The solution of the evolution equations for the field operators in these eigenmodes has the form of the Bogolyubov transformation, which allows a scattering matrix to be obtained for arbitrary values of the parametric gain. This scattering matrix can describe both the production of biphoton pairs and the generation of intense fluxes of correlated optical-terahertz fields that form a macroscopic quantum state of radiation in two spectral ranges.

Two-Colour Spectrally Multimode Integrated SU(1,1) Interferometer

“…In addition, proper spectral engineering of PDC sources allows the creation of correlated photons of different colours. During the last decade, the realisation of such non-degenerate PDC sources with specific spectral features has become widespread [30][31][32][33], while their application in interference systems such as Hong-Ou-Mandel [34] and nonlinear Mach-Zehnder interferometers [33] seems to be very promising.…”

Two-colour spectrally multimode integrated SU(1,1) interferometer

“…In addition, proper spectral engineering of PDC sources allows the creation of correlated photons of different colours. During the last decade, the realization of such non-degenerate PDC sources with specific spectral features has become widespread [27][28][29], while their application in interference systems such as Hong-Ou-Mandel [30] and nonlinear Mach-Zehnder interferometers [19] seems to be very promising.…”