I know when you interfere two beams you get an interference pattern with a fringe pattern of λ/(2*sin(θ/2)) in physical space. It seems that there must also be modulation of the spectrum. Is this true, and if so, how do you calculate what it looks like?
As a follow-up if there is spectral interference fringes to observe, would the spectral modulation be observable at any location in the physical pattern, or would it present itself as a change in wavelength across the interference pattern? Practically, would you want to collect a large amount of the physically overlapped beam and send it through a spectrometer to observe the pattern in the spectrum, or perhaps a small probe that would scan across the pattern in physical space?