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We analyse the dispersion relation of a one-dimensional (1D) metal-dielectric (MD) structure for H-polarized light (i.e. the magnetic field is parallel to the interfaces of the layers) and use the transfer matrix method to simulate the subwavelength image effect through the 1D-MD structure. The structure operates in the self-collimation regime, and does not involve negative refraction or amplification of evanescent waves. The Fabry–Perot resonance effect is studied in order to obtain optimum parameters for maximum transmission. A resolution of λ/10 for a single point source is achieved when the thickness of the 1D-MD is about 300 nm. Taking into account the actual values of the dielectric constants of the metal (silver) and the dielectric (HfO2) layers, we find that a silver/HfO2 stack, with suitable parameters, has a resolution of λ/5 at visible wavelengths.

We investigate the Goos–Hanchen effect of a Gaussian light beam reflected by the thin-film Fabry–Perot filter. It is shown that the Goos–Hanchen shift can be either negative or positive. The Gaussian-beam analysis and stationary phase method are introduced to calculate the lateral shift between the incident beam and the reflected beam at different wavelengths and to analyse the Goos-Hanchen effect in the thin-film Fabry-Perot filter. The effect of the incident beam diameter is also discussed.

The new phase grating based on two-dimensional structured thin films is reported. The rigorous coupled-wave analysis (RCWA) is employed to calculate the diffraction efficiency which varies with incident wavelength and angle. According to the result obtained by using RCWA, when the wavelength ranges from 600 to 640 nm, TE mode and TM mode can be diffracted in the transmitted 0th and ±1st orders, respectively, at normal incident angle. For example, at the wavelength of 633 nm, the polarization extinction ratio of 0th order is I0,TE/I0,TM=109.8, and the polarization extinction ratio of ±1st order is I±1,TM/I±1,TE =334.6. This polarizing beam splitting phenomenon is confirmed by theoretical simulation with finite-difference time-domain method, which shows that TE mode and TM mode can be separated by an angle of about 10°in glass substrate. The same simulation method is performed for the diffraction at incident angle of 23° in order to compare with the results from RCWA and grating equation calculation.

Electric field modeling of nodular defects is performed to investigate the interaction between defective multilayer coatings and Gaussian profile laser beam. Light intensity is significantly enhanced as large as 6 times within the nodular defects. Different geometries of defects irradiated by laser beams at 0 to 40 deg incident laser angles are analyzed. Nodules with large but shallow seeds, or irradiation of 40 deg p-polarized laser beam, tends to produce the greatest enhancement effect.

A numerical method to simulate the splitting of the reflected Gaussian beam in the thin-film Febry-Perot filter is described. The splitting can be simply explained by studying the reflection curve. The thin-film Febry-Perot filter has been fabricated by coating TiO2 and SiO2 on glass. The reflected beam splitting phenomenon is observed and measured in practice. The theoretical result is in accord with the experimental result.

The dispersion curve of one-dimensional metal-dielectric structure is calculated, and the finite-difference time-domain (FDTD) method is used to simulate the self-collimation in one-dimensional metal-dielectric structure, to which a Gaussian beam is incident at different angles. The influence of the dissipation of the metal layer on self-collimation is discussed. Subwavelength imaing with the one-dimensional metal-dielectric structure is also analyzed. The resolution of λ/8 is achieved for single point source when the thickness of 1DMD is equal to λ/2. The resolution will gradually degrade as the source moves beyond the near-field domain. Imaging with double slits source is also demonstrated, and a resolution of λ/3 is achieved.

The negative refraction phenomenon in wavy two-dimensional (2D) photonic crystals (PC) is investigated with the iso-frequency surfaces of PC and incident medium. The finite-difference time-domain method is used to simulate the negative refraction of incident Gaussian beam with different wavelengths and incident angles. When the incident angle is set at 45 degrees, the linear relation exists between the negative refraction angle and the wavelength within the range from 1485 to 1530nm, which is suitable for the superprism effect. In order to increase the transmission when negative refraction happened at large incident angles, interface projection method is employed.

The equal-frequency surface of wavy two-dimensional (2D) photonic crystals (PC) is obtained by virtue of plane wave expansion method. From the equal-frequency surface, we find a iso-frequency contour of rectangular form. A flat dispersion relation exists at this frequency, which is suitable for the self-collimation. The finite-difference time-domain (FDTD) method is used to simulate the self-collimation in wavy 2DPC on which a Gaussian beam is incident at different angles. Subwavelength lensing by self-collimation is also available in wavy 2DPC. The resolution of 0.28λ is achieved when single source is employed in simulation. The resolution will gradually degrade as the source moves beyond the near-field domain.

The necessary conditions of all-angle polarization beam splitting effect of photonic crystal is discussed from the aspects of band structure and equal frequency surface. The conservation law of the tangential k-vector component is illustrated in the equal frequency surface. In order to theoretically verify the all-angle polarization beam splitting effect, finite-difference time-domain (FDTD) method is employed to simulate the propagation of Gauss beam in the multi-layered wavy films, getting the transmission coefficients for the TE and TM modes in the angle range from 8° to 89° respectively.

Based on the mechanism of automatic shaping, the corrugated multilayer films of two_dimensional (2D) phtonic crystal is designed.This structure realizes omnidirectional polarization splitting with TM mode passing window between λ＝148 and 152μm, which is the complete band gap of TE mode. The variable rang es of the slope angle of the layers and the width of a-Si single layer are 38° —49° and 014—015μm, respectively. Band structure has been used to expl ain the omnidirectional polarization effect. An arrow-end_like 2D photonic cryst al which is the deformation of the corrugated multilayer films is introduced for comparison. It can only work as a wide-angle polarization splitter not as an o mnidirectional one for wavelength from 128 to 131μm. The comparison of th e band structures of these two different 2D photonic crystals leads to the metho d of extending the incident angle of polarization splitter.