Attenuate a laser line, blocking more than 99.9% (OD 3) of light in a 15–40nm band width. The average transmission outside the stopband is 75%, with the exception of those spectral regions where higher and lower harmonics result in high reflectivity. These rejection regions recur at wavelengths that are approximately 0.8 times (on the short wavelength side) and 1.25 times (on the long wavelength side) the principal rejection wavelength. RB filters can be designed to reflect up to three distinct bands and to operate at non-normal angles of incidence.