lasers
Wavelength tuning and linę narrowing in
s stack of birefringent plates (quartz) inserted in the cavity s in Brewster’s angle (no loss for vertical polarization) s thicknesses, e.g., in ratios 1:2:4 s optical axis in the piane of the plates s wavelength tuned by rotaing the stack about the surface normal
Freguency
s in rotation, all curves move in concert