Modeling of enhanced spontaneous parametric down-conversion in plasmonic and dielectric structures with realistic waves

Abstract

A numerical study of the enhancement of the spontaneous parametric down-conversion in plasmonic and dielectric structures is considered. The modeling is done using a nonlinear transfer-matrix method which is extended to include vacuum fluctuations and realistic waves (e.g. Gaussian beam). The results indicate that in the case of short-range surface plasmon polaritons, the main limiting factor of the enhancement is the short length of the coherent buildup. In the case of long-range surface plasmon polaritons or dielectric guided waves, the very narrow resonances are the main limiting factor instead.

Steps toward the experimental realization of surface plasmon polariton enhanced spontaneous parametric down-conversion

“…The main limitation is the short coherent buildup length (≈ 64 µm) caused by the losses. However, the process of SPDC requires a long coherent buildup distance (several millimeters) for the yield 10 −12 and 64 µm long coherent buildup distance only permits yield 10 −20 -the yield is still small (10 −16 ) after the predicted enhancement by SPPs and below the detection limit of our setup [12]. Despite it, the SPP-enhanced SPDC has still high potential in miniature sources: the short coherent buildup is not a problem and the enhancement factor up to four orders of magnitude is still available.…”

Photon superbunching from a generic tunnel junction

“…Even bunching from coordinated electron tunneling is unlikely because this process is quadratic in the current ( 27 ). We speculate that photon pair creation may be possible due to spontaneous parametric down-conversion of plasmon polaritons ( 28 ), which is enabled by the optical nonlinearity of the nanometer tunnel junction between the metals ( 29 ), with the small tip extension alleviating phase-matching conditions. The presence of optical resonances in the junction at energies corresponding to about half the high tunneling electron energies available (Fig.…”

Nanoscale nonlinear plasmonics in photonic waveguides and circuits

“…Experiments that rely on nonlinear plasmonics processes to generate quantum states are rare: guiding entangeld multi-photon states through the lossy media too easily destroys them. Recent efforts have attempted to use guided surface plasmon polaritons to enhance spontaneous parametric downconversion [272], and some initial steps have Coherence requires that the spontaneous emission time t sp be shorter than dephasing events with characteristic time scale t deph . Dielectrics optain long t deph by cooling; plasmonics achieve short t sp via a fast spontaneous emission rate (i.e., large Purcell factor).…”