Multiple Beams of Equal Intensity Monochromatic Light From a Single Source
Original Publication Date: 1985-Sep-01
Included in the Prior Art Database: 2005-Feb-19
By means of a totally reflecting mirror and a multilayer, partially reflective and partially transmissive dielectric filter placed at an angle to one another (as shown in the figure), a single beam of monochromatic light can be split into multiple beams having equal intensity. A method is described for selecting 1) the characteristics of the filter, 2) the angle (a) between the two mirror surfaces, and 3) the angle of incidence (r) of the input beam to produce output beams of equal intensity. As shown in the figure, the input beam strikes the filter at an angle and a part of the beam is transmitted while a larger part is reflected. The reflected beam is again reflected by the mirror and strikes the filter again, this time at a different angle. Again, part is transmitted and part reflected.