The electric field intensity of the THz radiation from YBCO thin films excited by ultrashort laser pulses has been enhanced by a factor of 3 using a-axis oriented films instead of c-axis oriented ones used previously under the same excitation conditions. This corresponds to the enhancement of a factor of 10 for the radiation power. From the transmittance measurements of the millimeter wave for a-and c-axis oriented films, the origin of the enhancement is attributed to the increased fraction of the THz electromagnetic wave power transmitted from the YBCO film to free space. This result indicates that the utilization of the anisotropic properties of high-Tc superconductors is effective to enhance the radiation power.

A new type of guided-wave polarization splitter is proposed for the operation at optical frequencies. The basic structure of the device is a bifurcating waveguide fabricated in a uniaxial crystalline material such as LiNbO3. The splitting behavior of optical waves into two waves with mutually perpendicular directions of polarization by an optically anisotropic material is utilized in the branching section of the present polarization splitter. Once of the conspicuous features of the device is free of any electrical control via the electro-optic effects. Some numerical results obtained with the finite difference beam propagation method indicate that extinction ratios better than 20dB are possible of realization for both TE and TM modes.

In order to investigate the characteristics of the superconducting gap structures of BSCCO oxide superconductor, tunneling spectrum measurements were carried out with several junctions on the bulk single crystal surfaces. Point contact tunneling studies by means of the M/I/S and S/(I)/S junctions have shown the reproducible gap values, 2Δ (//c-axis) of 402 meV, at the cleaved crystal surfaces, and the ratio of 2Δ(//)/kBTc5.50.3 indicates the strong coupling superconductor of this material. Somewhat larger gap values, 2Δmax(c-axis)701 meV, have been also observed at the lateral surface, and these various gap values observed on each surface of the same crystal indicate the characteristic of the large gap anisotropy, Δ()/Δ(//)1.8, of this material.

In this paper, scattering waves by a strip grating with an anisotropic substrate for the incidence of inclined polarization are analyzed, and polarization characteristics of scatterd waves are calculated. For simplicity, the analysis is limitted to the case of normal incidence and a perfectly conducting strip grating is assumed.