Figure 2: Experimental setups.
From: Photon extrabunching in ultrabright twin beams measured by two-photon counting in a semiconductor
(a) The source is based on a non-linear crystal (χ(2)) pumped at 780 nm by a mode-locked Ti:sapphire laser delivering 10 ps pulses at 80-MHz repetition rate. The dispersion of the twin beams is compensated by a backward and forward propagation in a SF14 glass prism pair. The collimated beam then passes through the Michelson or modified Mach–Zehnder interferometer before being focused by a 26-mm aspheric lens (Asph. L) on a two-photon counter (TPC). Estimated focal spot on the detector is 5 μm. (b) The Michelson interferometer consists of two arms that are common for both signal and idler: BS is a 50/50 beam splitter, M and Mτ are golden mirrors and the time delay τ is adjusted by translating Mτ. (c) The modified Mach–Zehnder interferometer consists of two separate paths for signal and idler, which are split towards the two individual paths by a dichroic mirror (Ms,i) reflecting signal and transmitting idler wavelength. The time delay τ is explored on the signal path.
