a triangular prism with an apex angle slightly less than 180°: when illuminated by a point source of light it produces two overlapping beams that form an interference pattern on a screen.
Origin of biprism
Also called Fresnel biprism.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for biprism
Historical Examples of biprism
In lieu of the biprism, reflectors may be invoked to double the original source of light.
a prism having a highly obtuse angle to facilitate beam splitting
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012