Planar corner-cut square microcavities: ray optics and FDTD analysis.

We analyze corner-cut square microcavities as alternative planar microcavities. Ray tracing shows open-ray orbits that are 90-degree-rotated can oscillate between each other upon reflections at the 45-degree corner-cut facets, and have the same sense of circulation. Our two-dimensional finite-difference time-domain simulations suggest that a waveguide-coupled corner-cut square microcavity with an optimum cut size supports traveling-wave resonances with desirable add-drop filter responses. The mode-field pattern evolutions confirm the concept of modal oscillations. By applying Fourier transform on the mode-field patterns, we analyze the modal composition in k-space. The add-drop filter responses can be optimized by fine-tuning the waveguide width.

Mode field patterns and preferential mode coupling in planar waveguide-coupled square microcavities.

We report a numerical and analytical study of mode field patterns and mode coupling in planar waveguide-coupled square microcavities, using two-dimensional (2-D) finite-difference time-domain (FDTD) method and k-space representation. Simulated mode field patterns can be identified by k-space modes. We observe that different mode number parities permit distinctly different mode field patterns and spectral characteristics. Simulation results suggest that k-space modes that nearly match the waveguide propagation mode have a relatively high coupling efficiency. Such preferential mode coupling can be modified by the mode number parity.

Public awareness, attitude, and understanding of epilepsy in Hong Kong Special Administrative Region, China.

PURPOSE: Because of the nature of the epileptic seizure, the social stigma attached to epilepsy is a major handicap to persons with epilepsy compared with the disability associated with seizures or the side effects from medications. Measuring the awareness, attitude, and understanding of epilepsy is the first step in alleviating discrimination. METHODS: We conducted a face-to-face questionnaire interview survey in five different locations (HKSAR) that represented the population structure, administrative function, and occupations of inhabitants. Subjects with epilepsy or with relatives who had epilepsy were excluded. RESULTS: We interviewed 1,128 subjects; 58.2% had heard about epilepsy before. Of these, 55% had witnessed one or more epileptic seizure, and 18.9% knew one or more persons with epilepsy; 52.7% would put an object into a patient's mouth during an epileptic seizure to prevent injury of the tongue (32.2% learned this from a local television program), and 94.1% agreed that persons with epilepsy could be married. However, only 72.5% considered pregnancy to be appropriate; 11.2% would not let their children play with others with epilepsy; 32.2% would not allow their children to marry persons with epilepsy. Employers (22.5%) would terminate the employment contract after an epileptic seizure in an employee with unreported epilepsy. CONCLUSIONS: This study documented the public attitude toward epilepsy in HKSAR; although it was more negative than that in Western societies, it was more positive than that of the Chinese in China or Taiwan. We suggest that more effort be made to improve public awareness of, attitude toward, and understanding of epilepsy through school education and epilepsy-related organizations in HKSAR.