A tightly stretched, extremely thin polymer film mounted on a frame. In laser setups, pellicles are used as beam splitters because they are so thin that they eliminate ghosting and chromatic dispersion that occur with thick glass plates. They are also used in lithography to seal photomasks from dust without distorting the imaging light.
Don't sneeze near the setup, you'll rupture the pellicle on the beam splitter.
Pellicles are incredibly fragile; never touch the membrane or attempt to clean it with compressed air.
Also heard as
- pellicle beam splitter
Related terms
Beamsplitting
The process of dividing a single beam of light into two or more separate paths.
Ghost
A weak stray beam from a back-surface reflection that travels off in an unexpected direction or focuses somewhere it should not.
Thin-film interference
The optical phenomenon where light waves reflecting off the top and bottom boundaries of a thin coating interfere with each other.