Single wall carbon nanotubes (SWCNTs) can be metallic, depending on their chirality. For their nanoscale geometric
dimension, SWCNTs can be used as antennas to convert high-frequency electromagnetic radiation such as optical
radiation into localized energy and vice versa. However, at optical frequencies, traditional antenna design theory fails for
metals behave as strongly coupled plasmas. As a matter of fact, an optical antenna responds to a shorter effective
wavelength which depends on the material properties and geometric parameters. In this letter, we derived the
relationship of effective wavelength with the wavelength of incident radiation for SWCNTs optical antenna, assuming
that the SWCNTs can be described by a free electron gas according to the Drude model. SWCNTs optical antenna holds
great promise for increasing solar energy conversion efficiency.
Photoacoustic spectroscopy (PAS) is a powerful tool for the study of the absorption spectra of solid samples. Scattered light, which used to be a main error source in conventional absorption spectroscopy, is not a problem for PAS, and furthermore, in this paper it is helpful for photoacoustic spectroscopy measurement. In this work, the photoacoustic spectra of an olanzapine tablet and its powder have been investigated. Differential analysis was used to eliminate the background signal generated by the photoacoustic cell. It is found that the photoacoustic spectrum of olanzapine in the powdered olanzapine tablet has the same spectral features as that of the pure olanzapine powder, while the photoacoustic spectrum of the olanzapine tablet does not have, although the ingredients in both are completely the same. This phenomenon can be interpreted as the light scattering effects in the powdered olanzapine tablet. The light scattering effects in a solid mixture amplify the photoacoustic spectral features of the main light-absorbing ingredient in the mixture, rather than enhance the measured photoacoustic signal over the whole measured wavelength range, which is different from the influence of light scattering effects on a single-ingredient solid powder. Based on this work, a method is proposed to preliminarily fast identify the light-absorbing ingredient in a solid mixture. Using the method, a drug tablet can be measured directly in solid state and hardly need sample preprocessing, and thus the time for composition analyses will be reduced significantly.
Multi-spectral Guidance is most important in the development of modern Optical Guidance System. This paper advances
a scheme of spectrum-dividing system used in the multi-spectral guidance optical system. The scheme introduces
prismatic technology into the design of optical system of the Guidance System. Combining characters of optical
thin-films and prisms and optimizing filmy parameters by Simulated annealing algorithm so that it can divide the
multi-spectrum into available spectrums completely. Consequently, a miniature, lightweight spectrum-dividing
construction, suitable for different wavelengths, has achieved. It satisfies the requirements of a multi-spectral optical
guidance system. And the spectrum-dividing system designed in this paper can divide a wide spectrum ranged from 0.4
to 5.0μm into three spectra, which are visible, short-infrared and medium-wave infrared separately. Compared with the
traditional guidance system, it can improve the detecting capability effectively.
The study on the scattering characters of the targets scattered by the polarized light, is a very important approach to study
the characters of the targets. Based on the scattered model of the non-spherical particles, the Mueller matrix can be
calculated using the vector radiative equation. The change of the polarization degree vs. parameters of the scattered
medium will be discussed in this article.
A binary optics method has been adopted to improve upon a conventional optical system in guidance and control, and a
hybrid broadband imaging system that includes a binary surface is analyzed and evaluated by optical design software
ZEMAX. The practical design shows that the introduction of binary optics can simplify the structure of the imaging
system and reduce the size and weight of the broadband guidance and control system. Moreover, it can help to acquire
images of radiation of different wavelengths from targets; hence it will result in improved overall performance of
missiles in wars.
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