Tunable up-conversion detector for single photon and bi-photon infrared spectroscopic applications

摘要

A tunable waveguide-based frequency up-conversion detector is used for single photon level near infrared (IR) spectroscopic measurements. Applications include direct spectroscopic measurement of week near IR signals and remote bi-photon spectroscopy. We have demonstrated direct spectroscopy of single photon near IR signals from a greatly attenuated laser and a single photon source. We further applied the up-conversion spectrometer for frequency correlated bi-photon spectroscopy using a single photon source of non-degenerate photon pairs at 1310 ran (near IR) and 895 nm. In correlated bi-photon spectroscopy, the spectral function at one wavelength range of a remote object can be reproduced by locally measuring another (near IR) wavelength range using the up-conversion spectrometer and monitoring the coincidence counts. A near IR single photon detection efficiency of 32 % has been achieved with the up-conversion spectrometer. The spectral resolution of the system is approximately 0.2 nm at 1310 nm based on the acceptance width of the up-conversion chip used. In bi-photon spectroscopy, the spectral resolution for the correlated photons at 895 nm is approximately 0.1 nm. The sensitivity achieved using the up-conversion detector is -126 dBm at 1310 nm.