[Analysis of spectral properties of novel holographic transmission notch filter]

Optical filter has extremely important applications in spectroscopy, optical measurement and laser physics. Holographic filter, especially the transmission volume holographic notch filters using dichromate gelatin (DCG), is a new kind of filter with the main characteristic of a very narrow bandwidth. In this paper, measurements were carried out on the spectral properties of this transmission volume holographic notch DCG filter using an ultraviolet-visible transmittance spectrometer. The experimental results show that the relative transmittance of main spectrum of this filter is less than 2% in the visible region between 400 and 800 nm, and the relative transmittance of other spectra are more than 85%. Moreover, the filter has a narrow bandwidth with a half-bandwidth less than 12 nm, and a 1/10 width of the bandwidth less than 15 nm. These results indicate that this new kind of filter has an excellent filter characteristic to the main spectrum of Ar+ laser at the wavelength of 514.5 nm.