Fig. 1
From: Room-temperature ultrasensitive photon-level detection in the subterahertz frequency regime
Experimental setup of sub-THz wave detection. The red and blue lines indicate the paths of the generation pump beam and injection seeding, respectively. The pink path directs the other split pump beam toward a second PPLN crystal. The green path redirects the sub-THz wave into the rear side of the PPLNd crystal.
