Fig. 2
From: Security analysis of qutrit quantum secret sharing with linear optical correlation measurement
A schematic diagram for measuring an OAM value of a single photon. The OAM BSs change a direction of propagation of an incoming single photon according to its OAM value. OAM BS consists of a Mach-Zehnder interferometer with Dove prisms. The relative angle between the two Dove prisms in each arm of the Mach-Zehnder interferometer is denoted as \(\alpha /2\). In the setup, value one is added in the OAM value of an incoming photon by using an OAM hologram \((+1)\). Then the first OAM BS (\(\alpha /2=\pi /2\)) splits photons whose OAM value is odd and even, and the second OAM BS (\(\alpha /2=\pi /4\)) does photons whose OAM value is \(l=0\) and \(l=2\). Finally, the incoming photon enters into corresponding single photon detector.
