LISA Pathfinder flight optical bench
The Flight Optical Bench ready for integration into the LISA Pathfinder Technology Package.
The 20cm by 20cm block of Zerodur ceramic glass has the "tombstone" mirrors and beam splitters hydroxide-catalyst bonded to it.
The two optical beams arrive into the optical bench through the fibre injector optical subassemblies (FIOS) - seen with the green connectors. This light is then reflected and/or split by the "tombstones". One beam will reflect off the two mirrors to the left and the right of the optical bench that are being used to represent the free-falling test masses. The other beam stays within the bench.
The photodiodes, with the silver cables connecting them along the edge of the optical bench, are used to measure the beams after their paths through the bench and off the mirrors.