Parkhurst & Oliff
Light beam separation method
 A method of separating at least two light beams propagating in the substantially same direction but which propagate with making a small angle therebetween is disclosed, which comprises making one of said light beams incident upon an interface between an isotropic first optical medium having a first refractive index and an isotropic second optical medium having a second refractive index lower than said first refractive index at an incident angle substantially equal to the Brewster angle so that the light beam is substantially totally transmitted through said interface; and making the other light beam incident upon said interface at an incident angle greater than the critical angle so that the light beam is totally reflected by said interface. 
Olympus Optical Co., Ltd.
G
G02B
inventional
Tohru Kiichi Kenichi
Musha Kato Ito