Mechanical delay line
Adds an adjustable optical path to delay pulses, keeping the outgoing beam on its axis.
Open in the canvas →In the real world
A mechanical optical delay line changes the distance traveled by light using a translation stage and folding mirrors or a retroreflector. Time-resolved experiments use this change to vary the arrival of one pulse relative to another. The path multiplier depends on the number of passes through the moving section[1].
In OpticalSetup
Extra optical path specifies the added path directly, in millimetres. Do not multiply it by two again. Static mode holds one value; periodic sweep moves between the configured path limits. The outgoing beam keeps its axis while downstream pulse timing includes the added path.
The example adds 100 mm, corresponding to about 334 ps in vacuum. Compare the beam probes before and after the element, then change the path to see the timing offset change.
The folded path is represented by a compact element, not individually traced moving mirrors. It does not calculate carriage vibration, alignment drift, or stage acceleration. It delays pulses; it does not compensate their dispersion.