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Based on the theoretical analysis of biaxial birefringent thin films with characteristic matrix method, we investigate the phase shift on transmission of a tilted columnar biaxial film at normal and oblique incidence over 300-1200nm for s- and p-polarized waves. Compared with the simplified calculation method, the interference effects of the birefringent thin film are considered to yield more accurate results. The quarter wavelength phase shift calculated with the characteristic matrix method is consistent with that monitored with in situ measurement by two-angle ellipsometry, which validates our complied program for the calculation of the phase shift of the biaxial anisotropic thin film. Furthermore, the characteristic matrix method can be easily used to obtain continuous adjustable phase retardation at oblique incidence, whereas the simplified calculation method is valid for the case of normal incidence. A greater generality and superiority of the characteristic matrix method is presented. [ABSTRACT FROM AUTHOR]

Abstract: Polarizers respectively with broad polarizing region bandwidth, large layer thickness error tolerance and high extinction ratio are designed and prepared. Transmittance spectra of the prepared samples are measured at Brewster''s angle, and the results show that different requirements can be fulfilled by optimized designs. Spectral performance of designs with higher layer thickness error tolerance coincides better with the theoretical spectra. Laser induced damage threshold of the prepared samples are evaluated. Electric field distribution, defect, film absorption, and damage morphology are investigated, and the results indicate that electric field distribution in high index layers is the main reason that causes the difference of laser induced damage threshold. For both p polarized and s polarized light, the lower the electric field peak value and the farther the layer, which has the strongest electric field away from air, the higher the laser induced damage threshold. [Copyright &y& Elsevier]

A broadband, polarization-independent, and wide angle metamaterial absorber (MA) with tapered cylinder structures is investigated with finite difference time domain simulations. The titanium nitride (TiN) and indium tin oxide (ITO) thin film are introduced as the tapered cylinder structures. The unit cell structure is mainly composed of two pairs of TiN/ITO layers and one TiN base layer. The absorption is higher than 99% between the wavelength 700 nm and 1000 nm. The broadband, polarization independent average absorption remains above 95% between 400 nm and 1200 nm with a wide range of incident angles from 0° to 40°. The electrical field intensity distributions are studied to disclose the broadband absorption mechanism. This designed broadband absorber appears to be very promising applications in the plasmonic sensing and photovoltaic devices. [ABSTRACT FROM AUTHOR]

Abstract: Wave propagation of symmetry incidence on the biaxial birefringent film is discussed in this paper based on the characteristic matrix method. Furthermore, based on the refractive index surface, the refractive indices and effective optical admittances of the forward and backward propagating extraordinary waves (p-polarized wave) are analyzed in detail. With regard to the symmetry incidence, optical properties, such as the input optical admittance, transmittance and reflectance, are not identical for an extraordinary wave under common condition, i.e., angular selectivity. Based on an analysis of refractive index surface, the effective optical admittances of the forward and backward propagating extraordinary waves are equal in this particular case; transmittance and reflectance under the symmetry incidence are completely overlapped, similar to findings in the isotropic thin film. We validate our analysis using the developed software package. Based on the novel theory analysis, we can gain a new perspective of symmetry incidence about angular selectivity for the biaxial birefringent film. [Copyright &y& Elsevier]

Highlights: [•] Under the nanosecond laser irradiation, concentric ring structures filled with the periodic ripples are appeared on the exit surface of fused silica. [•] The effect of the incident energy on the damage sites and ripples has been investigated. [•] The dependence of ripple properties on the laser polarization and the incident angle has been systematically analyzed. [Copyright &y& Elsevier]

Abstract: Traditional periodic multilayer reflector working in the soft X-ray region should be placed at the designed incidence angle and wavelength, which is extremely difficult and complicate in practice especially for “near water window region” (4.43–6.50nm). In this region, Ni-like-Ta laser working at the wavelength 4.48nm provides a possible source which has caught a lot attention. In this paper, to overcome the shortcoming of the periodic structure, top-flat broad band (normal incidence) and broad angular (around quasi-Brewster angle) Cr/C non-periodic multilayer reflector have been designed for the 4.48nm soft X-ray optical system. In the wavelength region 4.473–4.488nm, 4.455–4.496nm and 4.435–4.529nm, mean theoretical normal-incidence reflectivity can get 35.0%, 24.2% and 12.6%, respectively, by the top-flat broad band reflectors. In the grazing incidence angle region 44.85–45.16°, 44.54–45.46° and 44.02–45.98°, mean s-component theoretical reflectivity at 4.48nm can get 39.7%, 23.1% and 13.0%, respectively, by the top-flat broad angular reflectors. [Copyright &y& Elsevier]