Narrow-band interference filters are classified into three types, laser/optical/visible and near-infrared. The half-peak bandwidths of the laser line interference filter are 1,3 and 10nm for a specific laser wavelength. The spectral line interference filter is a spectral line for an element with a half-peak bandwidth of 10nm. For visible light and near infrared interference filters, the corresponding wavelength is 300-1000nm, the central wavelength interval is 50nm, and the half peak bandwidth is 10 or 40nm.