Researchers at NIST have developed a new method for ultra-sensitive infrared spectrometry using single photons. The technique, based on frequency up-conversion technology, allows for highly sensitive spectral measurements in the near-infrared region (1,300-1,320 nm) with signals as weak as -126 dBm. This represents a three orders of magnitude improvement over existing commercial systems.
The key innovation is a periodically poled lithium niobate (PPLN) waveguide that converts near-infrared photons to visible light using a strong pump beam at 1550 nm. This allows efficient detection with silicon-based avalanche photodiodes (Si-APDs), which are not typically used in the near-infrared region.
The new spectrometry method offers several advantages over conventional systems, including reduced insertion loss, increased throughput efficiency, and the ability to operate in both polarization-sensitive and non-polarization-sensitive modes. The compact system is expected to find applications in various fields beyond quantum key distribution.
Keywords: Spectroscopy, Photon, Detection, Infrared, Spectrometer
