Fig. 1

Experimental setup for temperature sensor through beating of frequency entanglement. LD laser diode, HWP half wave plate, WP wave plate, ppKTP type-II periodically poled potassium titanyl phosphate crystal, TEC temperature controller, LP long pass filter, PBS polarizing beam splitter, Oven computer-controlled heating device, PC polarization controller, BS beam splitter, Detectors single photon detectors