User talk:Stone pp

I reversed your change to Fabry-Pérot interferometer. The formula was right as it was. Yes, it looks like the cosine should be in the denominator, but there is more going on than is immediately obvious. Because the reflected beams exit the etalon at an angle, there is an additional contribution to the phase difference due to the propagation outside the etalon. --Srleffler (talk) 01:04, 1 July 2009 (UTC)