[Analysis of reflective IR transmittance spectra at oblique incidence of micrometer SiO2 films on c-Si substrate].

The reflective infrared transmittance spectra at oblique incidence of SiO2 films deposited on c-Si wafer have been measured. The thickness of the films was micrometer quantity. The spectra showed many differences from the common transmittance (or absorption) spectra in the range of 900-1 250 cm(-1). The reflectivity peak at 1100 cm(-1) was found and its position was essentially fixed. With the thickness increased, the drop of peak at 1100 cm(-1) and hollow at 1200 cm(-1) became gradually slow. As the thickness increased to be over 2 micrometers, the shape of the spectra in 1075-1250 cm(-1) did not change obviously. The analysis showed that the measured spectrum was composed of reflectivity spectrum and absorption spectrum of the SiO2 film, which occurred at Air/SiO2 interface and SiQ2 layer respectively. When the thickness was over one micrometer and the film had considerable absorption, the contribution from reflectivity spectrum became very obvious. So the absorption is not the only factor in the analysis of these spectra.

[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.

[Study on spectral properties of Chinese herbal medicines additives in cosmetic].

Chinese herbal medicines as additives in cosmetic can both keep the properties of cosmetic and have maintaining, health protection and remedial effect. Some of the Chinese herbal medicines can absorb ultraviolet and cure sunburn. This article mainly studies the spectral properties of several kinds of Chinese herbal medicine additives in cosmetic by ultraviolet and visible spectrophotometer, and analyses the ultraviolet absorption of the Chinese herbal medicine additives. It was shown that gynostemma pentaphyllum can absorb ultraviolet very well. It can be a promising natural additive in the health protection cosmetic. Codonopsis pilosula, floss chrysanthemum indicum, radix scutellariae and radix glycyrrhizae can absorb ultraviolet. They can also be the additives, while ligusticum wallichii can't absorb ultraviolet, so it can not be used as the sunburn protection additive.