[Transmission efficiency analysis of near-field fiber probe using FDTD simulation].

A fiber probe is the key component of near-field optical technology which is widely used in high resolution imaging, spectroscopy detection and nano processing. How to improve the transmission efficiency of the fiber probe is a very important problem in the application of near-field optical technology. Based on the results of 3D-FDTD computation, the dependence of the transmission efficiency on the cone angle, the aperture diameter, the wavelength and the thickness of metal cladding is revealed. The authors have also made a comparison between naked probe and the probe with metal cladding in terms of transmission efficiency and spatial resolution. In addition, the authors have discovered the fluctuation phenomena of transmission efficiency as the wavelength of incident laser increases.

[Compatible low target feature coatings].

Indium tin oxide (ITO) film has low reflectance in near infrared band while high reflectance in infrared band, and its dielectric constant can be described by Drude free-electron model. SiO film has very strong absorption at certain infrared wavelength By combining them, certain spectral selectivity can be realized. In the present paper, the authors investigated SiO/ITO films in terms of spectrum selectivity, and discussed the influence of film structure on reflection spectrum. By means of the computation of reflection spectrum with characteristic matrix, the authors found that SiO/ITO film can be used as a compatible infrared low target feature coating by properly adjusting film arrangement and selecting suitable film parameters.

[A novel material with low infrared target features].

As the working mode of modem detecting system is changing from single mode to compound one, materials with certain spectral characteristics are required to meet low observable demands. In the present paper, the authors designed a novel material with low target features in infrared band based on one dimensional doped photonic crystal, and investigated the influence of the composite structure on reflection spectrum. It was found that under certain conditions, a local narrow low-reflectivity region can be formed within a wide high-reflectivity band in reflection spectrum, providing a reference for the development of a new type of infrared functional materials.