Sum-frequency-generation based terahertz detection using a periodically poled lithium niobate

Optical frequency up-conversion based on sum frequency generation is a promising technique for efficient single-photon detection because of commercially available detectors with high efficiency and low noise. We extended the frequency range of up-conversion detection based on sum frequency generation to far infrared at terahertz frequency using a periodically poled lithium niobate. Terahertz photon detection based on sum frequency generation was demonstrated. The photon conversion realizes terahertz photon detector operating at room temperature.