Generation of broadband spontaneous parametric fluorescence using multiple bulk nonlinear crystals

Abstract

Abstract:We propose a novel method for generating broadband spontaneous parametric fluorescence by using a set of bulk nonlinear crystals (NLCs). We also demonstrate this scheme experimentally. Our method employs a superposition of spontaneous parametric fluorescence spectra generated using multiple bulk NLCs. A typical bandwidth of 160 nm (73 THz) with a degenerate wavelength of 808 nm was achieved using two β -barium-borate (BBO) crystals, whereas a typical bandwidth of 75 nm (34 THz) was realized using a single BBO crystal. We also observed coincidence counts of generated photon pairs in a non-collinear configuration. The bandwidth could be further broadened by increasing the number of NLCs. Our demonstration suggests that a set of four BBO crystals could realize a bandwidth of approximately 215 nm (100 THz). We also discuss the stability of Hong-Ou-Mandel two-photon interference between the parametric fluorescence generated by this scheme. Our simple scheme is easy to implement with conventional NLCs and does not require special devices. power levels using tapered optical fibers in rubidium vapor," Phys.

Quantum interference in the presence of a resonant medium

“…It is on a par with existing high-performance femtosecond laser setups. With readily available methods for generation of broadband biphoton fields, it is feasible to achieve the temporal resolution down to a few femtoseconds or even less 53 – 55 . For example, SPDC generated in chirped crystals 53 yields the spectral width of 300 nm, which corresponds to the temporal resolution of 7 fs.…”

Quantum Spectroscopy of Plasmonic Nanostructures

“…Their pairwise correlation is measured by an electronic coincidence circuit, which produces a signal (coincidence) if APD counts arrive within the fixed time window typically of about several ns. Dedicated techniques, allow obtaining the widths of the SPDC spectra in a given spatial mode in the range of several hundreds of nanometers [25][26][27][28].…”

Broadband biphotons in a single spatial mode

“…On the other hand, our method is limited by the spectral region, where phasematching and grating dispersion curves coincide, whereas other spectral broadening methods, based on utilizing inhomogeneous nonlinear media [26,[30][31][32][33][34], are completely free of this limitation. At the same time, the biphoton field, generated in inhomogeneous nonlinear media, cannot be kept Fourier-limited, and additional compression techniques are required [17,45,46].…”

“…Biphoton generation in inhomogeneous nonlinear media (a set of crystals [30], chirped crystals [5,31], crystals with a spatially modulated refractive index [32][33][34]) leads to inhomogeneous spectral broadening. Up to 154 THz bandwidth of the SPDC spectrum was obtained [34], but such inhomogeneous broadening inevitably leads to a Fourier-unlimited field.…”