Fig. 4
From: Simultaneous entanglement swapping of multiple orbital angular momentum states of light
A detailed schematic of the experimental setup. L1000: lens of focal length 1000 mm. L75: lens of focal length 75 mm. BBO0: 0.5-mm-thick β-barium borate crystal. L100: lens of focal length 100 mm. BF1: two consecutive bandpass filters at 405 ± 5 nm. SF: 100-μm circular aperture. L50: lens of focal length 50 mm. BBO1: 1-mm-thick β-barium borate crystal. DM: dichroic mirror. BBO2: 1-mm-thick β-barium borate crystal. LF: longpass filter, cutoff wavelength 750 nm. L150: lens of focal length 150 mm. L300: lens of focal length 300 mm. SLM: spatial light modulator. L400: lens of focal length 400 mm. BF2: bandpass filter at 808 ± 1.5 nm. BF3: bandpass filter at 810 ± 10 nm. L200: lens of focal length 200 mm. TS: translation stage. BS: non-polarising beamsplitter. L2: lens of focal length 2 mm. SMF: single-mode fibre. MMF: multi-mode fibre. SPAD: single-photon avalanche diode
