Entangled Two-Photon Absorption in Commercial Fluorophores

Abstract

Our study addresses the applicability of simple and common fluorophores for entangled two-photon fluorescence microscopy. Using CW-pumped SPDC waveguides, we can measure linear absorption rates of entangled photons in standard fluorophores in life science.

Visible and near-IR entangled photon generation and UV second harmonic generation with lithium niobate nanophotonic waveguides for on-chip spectroscopy

“…Even with the limitations of the pump laser used here, the nanophotonic device presented in this work exhibits substantially improved brightness and efficiency compared to the state of the art for visible photon pair sources. 25,26 Our visible-near-IR device demonstrates improved efficiency and brightness even over other TFLN sources at the better-explored telecom band 12,58,59 and has comparable performance to the most efficient telecom TFLN source (Ref. 6 ) to date.…”

“…The device produces an on-chip efficiency of (2.3 ± 0.5) × 10 11 pairs/s/mW, which corresponds to a per-photon conversion efficiency of more than 1 photon pair converted in every 10,000 pump photons ((1.1 ± 0.2) × 10 −4 pairs/s/photon). This efficiency is nearly two orders of magnitude better than visible-light diffused waveguide SPDC sources 25 and is on par with the leading TFLN sources in the better-explored telecom regime. 6 The SPDC from this device exhibits a broad spectrum centered at 811 nm with a degenerate FWHM bandwidth of 117 nm and an average brightness of (1.6±0.3)×10 9 pairs/s/mW/nm, a number limited by at least an order of magnitude by the pump laser linewidth (0.8 nm).…”

“…22 To date, there have been relatively few UV, visible, and near-infrared (NIR) TFLN devices compared to IR and telecom devices. For entangled photon pair production, the best visible and NIR photon pair sources are still large-area waveguides [23][24][25][26] and bulk periodically poled crystals. 23,[27][28][29][30][31][32] Similarly for UV generation, the few reported devices have been limited to large-area waveguides, 33,34 nanoparticles, 35 and metasurfaces.…”