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We describe a simple experiment which allows unequivocal determination of optical phase change upon reflection of light at the mica-silver interface. While the physical origin of such a phase change at the dielectric-metal interface is well understood to lie in absorption of electromagnetic energy by the metal, inconsistency and ambiguity has persisted as to what its sign and magnitude should be in the field of thin film optics. Most commonly, it has been assigned to be negative for mathematical convenience or just arbitrarily. Our finding shows that with the convention exp(-iωt) for time dependence of the electromagnetic wave, the phase change at the interface between mica and the thin silver film is necessarily positive and its magnitude falls between π and 3π/2 for silver thicknesses down to nanometres. This gives a physically reasonable correspondence to an increased equivalent thickness of the dielectric material, and it clarifies the assignment of interference orders in the harmonic series in a spectrum.

A simple method for determining both the size and the refractive index of spherical transparent particles, being larger in size than the wavelength of illuminating light, is proposed on the theoretical basis of geometrical optics of light scattering. In the theory, the intensity distribution of scattered light at a certain off-axis angle range of a few degrees can be recognized as interference fringes due to two dominant light rays from the particle. The ratio between the interference fringe contrasts of the scattering patterns in parallel and perpendicular polarization components is used to determine the refractive index of particles, whereas the size of particles is evaluated from the fringe pitch. Experiments were performed to confirm the validity of the proposed method. The validity range of the method is also discussed in terms of the light rays scattered into the observation angle. The present method has the advantage that measurements of the absolute intensity are not required to obtain the size and the refractive index of particles.

We present a simplified structure made of periodic metallic layers on a glass substrate, which offers a potentially simpler approach to building photonic crystals. Using microwave experiments and Fresnel formulas, we investigate the refractive index properties of these structures. We make both transmission and reflection measurements and find that the refractive index of a periodic layered media decreases depending on the periodicity of the geometric arrangement, dielectric contrast and filling fraction of metallic layers. It is shown that metallic layers lead to a substantial change of interference pattern which can be interpreted as a result of interference in a uniform medium with a refractive index smaller than 1.

A transmission-mode GaAs photocathode includes four layers of glass, Si3N4, Ga1−xAlxAs and GaAs. A gradient-doping photocathode sample was obtained by molecular beam epitaxy and its transmittance was measured by spectrophotometer from 600 nm to 1100 nm. The theoretical transmittance is derived and simulated based on the matrix formula for thin film optics. The simulation results indicate the influence of the transition layers and the three thin-film layers except glass on the transmittance spectra. In addition, a fitting coefficient needed for error modification enters into the fitted formula. The fitting results show that the relative error in the full spectrum reduces from 19.51% to 4.35% after the formula is modified. The coefficient and the thicknesses are gained corresponding to the minimum relative error, meanwhile each layer and total thin-film thickness deviation in the module can be controlled within 7%. The presence of glass layer roughness, layer interface effects and surface oxides is interpreted on the modification.

An integrated analysis system based on thin film optics, thermal transfer and electromagnetics is developed. Thermal conductivity and generated heat are discussed for mark formation. The simulations of multilayer calorific sources and multibeam heating sources using the finite element method (FEM) are investigated. The readout of nanometer-scaled marks based on computational electromagnetics using the finite-difference time-domain (FDTD) analysis is discussed. The real marks captured with microscopes can be analyzed using this integrated analysis system combined with digital image technology. Material models in the electromagnetic vector method are discussed with reference to different layers of disk. It provides a powerful tool for structure design and failure analysis of phase-change optical disks.

The absorptance spectra of a-Si:H films thinner than 0.5 µm are distorted by the presence of only a few interference fringes, which makes the determination of the Urbach energy (UE) difficult. The interference effect is analyzed by computing the absorptance spectrum as a function of the film's thickness t. The difference between the UE derived by exponential interpolation and the actual UE reaches a maximum of 17 meV for t ≈220 nm, and it can not be neglected even for films thinner than 100 nm. We measured the photothermal deflection spectroscopy spectra for several film thicknesses and corrected the UE by numerically fitting the spectra.

We report far-infrared reflectance spectra of Al x Ga1-x As/GaAs superlattices with various aluminium (Al) mole fractions (0.1

The classical McIntyre formula for p-polarized light incident on a thin film on a substrate is extended in general terms to include a realistic description of the interfaces and the possible excitation of plasma waves in the film. An earlier extension is critized and criteria are given for when the classical result is applicable.