Rugate coatings are usually defined as optical coatings that present a continuous variation of refractive index in the
direction perpendicular to the film plane. Such kind of optical coating has optical and mechanical properties that differ
from those of conventional high-low-index stacks. Especially, the broad angle range and the low optical scatter level
make them superior to traditional stacks. Antireflective (AR) coatings have found increasing applications. In this paper,
the principal aspects of rugate coatings theory are discussed and the emphasis is focused on polarization effect of the
incident light. The reason accounting for difference of the transmissivity was analyzed in the case of polarization and
board angle incidence. To eliminate polarization effect, a method of designing antireflection coatings using rugate
coatings was demonstrated. Antireflection coatings for the ultraviolet spectral region in the wavelength range 300-400
nm and incidence angle from 0 to 80 degree were designed. Then the implementation of optimization recurred to optimac
and conjugate gradient. It shows that the result of optimization is ideal. For AR coatings, this design method can enhance
the ratio of utilization of optical energy.
The detection of explosive agents is becoming more important and receiving much greater emphasis for homeland
defense. Raman spectroscopy is a well established tool for vibration spectroscopic analysis and can be applied to the
field of explosives identification and detection. The major bands of the Raman spectroscopy of industrial TNT
(Trinitrotoluene, CH3C6H2(NO2)3) are analyzed and seven prominent peaks, that is 1616.9cm-1 (C=C aromatic
stretching vibration), 1533.9cm-1 (NO2 asymmetric stretching vibration), 1360.1cm-1 (NO2 symmetric stretching
vibration ), 1210.5cm-1 (C6H2-C vibration), 822.9cm-1 (nitro-group scissoring mode), 792.3cm-1 (C-H out-of-plane bend),
and 326.7cm-1 (framework distortion mode) are used to identify the TNT. The Raman spectroscopes of TNT solved in
acetone at different mass ratios are studied, and the TNT in the solution can be detected correctly according the relative
distance, intensity, and peak area of the seven peaks. The TNT prominent peaks appear clearly in high level solution (the
mass ration of TNT and acetone is more than 1:10). With the decrease of TNT concentration in solution, the signature of
TNT becomes more and more weak. The low detection limit of TNT is limited by the noise of the instrument (NXR
FT-Raman accessory module with Nicolet 5700 FT-IR spectrometer is used for our experiments. The low detection limit
in our experiments is mass ratio 1:200, which is about 4mg/mL). The prominent peak heights are discussed in
consideration of the TNT concentration. Taking one of the acetone's peaks (1716.9cm-1) as the internal standard line, the
relative height of the prominent TNT peaks is almost proportional to the concentration of the TNT in the solution. A
fitting curve for the relations of prominent peak height according to the concentration is proposed with multinomial
fitting method, which can be used to analyze the concentration of TNT more accurately.
Solar blind ultraviolet communication systems can provide short to medium range non line-of-sight and line-of-sight
links which are covert and insensitive to meteorological conditions. These unique properties endow solar blind
ultraviolet communication systems increasing applications. While optical filters are key components of these solar blind
ultraviolet communication systems. Although filters can be designed in different forms, thin-film interference narrow-band
filters are widely adopted. In this paper, we make use of NCNBIF, which was so-called nonconventional narrow-band
interference filters proposed by Jerzy Ciosek firstly, to design ultraviolet narrow-band interference filters.
Generally, classical narrow-band interference dielectric filters, such as Fabry-Pérot filters, have a half-wave-thickness
spacer layer. In contrast with a classical interference filter, the NCNBIF does not have a half-wave-thickness spacer
layer. This spacer layer of NCNBIF consists of two different materials. This new kind of film system (NCNBIF) is
synthesized by using needle optimization technique, and possesses desired spectral characteristics.
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