View Single Post
Nov13-12, 05:29 PM
Sci Advisor
PF Gold
sophiecentaur's Avatar
P: 12,170
Wouldn't the main beam (main maximum) be the same for a plane mirror as for a plane reflection grating? The path differences for all wavelengths would surely all be zero in the direction of the classical main beam (isn't that all about Fermat's Principle?).