Snapping single flying photons based on tunneling assisted multiphoton absorption

Multi-photon absorption (MPA) can be used to measure the temporal correlation of flying photons at a much shorter timescale within a maximum delay (about 1$^{\mathrm{\thinspace }}$fs) given by the Heisenberg principle. We first measure the 2PA and 3PA of GaAsP material by using a mode locked laser (Mira 900) with pulse width less than 100 fs (76 MHz), and obtain pronounced 2PA and 3PA at 60 mW and 130 mW respectively (wavelength: 900 nm). We further strengthen the absorption process by using an extra electrical field through photon assisted tunneling, and double the MPA coefficient by a bias voltage of 5 V. Then, we demonstrate the tunneling assisted MPA in GaAsP by a pump-probe scheme, and successfully snap flying single photons in 1550-nm telecom band by using a synchronous 900-nm fs sampling pulse train, which scanning the flying photons through a motorizing translation stage. Experimental results show that the time-domain width of the single photon is around 250 fs, and further statistical investigations demonstrate that the single photons follow subPoisson distribution with Mandel Q parameter of about -0.2, which means the photons are antibunching definitely.