Upconversion detection near 2 μm at the single photon level

Opt Lett. 2013 Dec 1;38(23):4985-7. doi: 10.1364/OL.38.004985.

Abstract

We have demonstrated upconversion detection at the single photon level in the 2 μm spectral window using a pump wavelength near 1550 nm, a periodically poled lithium niobate (PPLN) waveguide, and a volume Bragg grating (VBG) to reduce noise. We achieve a system photon detection efficiency of 10%, with a noise count rate of 24,500 counts per second, competitive with other 2 μm single photon detection technologies. This detector has potential applications in environmental gas monitoring, life science, and classical and quantum communication.