Cellophane as a half-wave plate

The last post on cheap optics reminded me of this 2003 paper where they showed that kitchen grade cellophane acts as a half-wave plate.

It was experimentally verified that an ordinary 25-????m-thick cellophane sheet possesses properties of a wide wavelength spectrum half-wave plate. Moreover, cellophane displayed superior performance when used for rotating the direction of polarization of white light than a commercially available half-wave plate with a specified wavelength. The retardance of the cellophane was measured to be 170°.

It may be added that the price per square cm2 of the cellophane half-wave plate is about 1/3500 of that of a commercially available half-wave plate.

Iizuka K (2003) Cellophane as a half-wave plate and its use for converting a laptop computer screen into a three-dimensional display. Rev Sci Instr 74(8):3636-3639. (link)