Hyperthermal neutral beam sources for material processing.

Hyperthermal neutral beams have a great potential for material processes, especially for etching and thin film deposition for semiconductor and display fabrication as well as deposition for various thin film applications. Plasma-induced damage during plasma etching is a serious problem for manufacturing deep submicron semiconductor devices and is expected to be a problem for future nanoscale devices. Thermal and plasma-induced damage is also problematic for thin film depositions such as transparent conductive oxide films on organic light emitting diodes or flexible displays due to high temperature processes in plasma environments. These problems can be overcome by damage-free and low-temperature processes with hyperthermal neutral beams. We will present the status of the hyperthermal neutral beam development and the applications, especially, in semiconductor and display fabrication and introduce potential applications of thin film growing for optoelectronic devices such as light emitting diodes.

High-power, low-noise, Yb-doped, cladding-pumped, three-level fiber sources at 980 nm.

We present results on a high-power, cladding-pumped, Yb-doped fiber emitting at 977 nm in laser and ampllified-spontaneous-emission source configurations. We obtained up to 1.4 W of fiber-coupled, single-mode output power and slope efficiency as high as 68%. To our knowledge these are the highest powers efficiencies achieved from a single-mode fiber laser at approximately 980 nm and the first demonstrated results on a high-power amplified-spontaneous-emission source in this wavelength range. High power and high slope efficiency are achieved by using a high numerical aperture (> 0.7), a jacketed air-clad fiber, and a high-brightness pump source. Both types of sources exhibit relative intensity noise below -130 dB/Hz and are thus suitable for a wide range of applications.

Displacements of the resonant peaks of a long-period fiber grating induced by a change of ambient refractive index.

We present a graphic method of analyzing the spectral displacements of a long-period fiber grating as a function of ambient index. Mode dependence of the maximum displacement, disappearance of a particular resonance peak, and spectral behavior when the ambient index is larger than that of the cladding material are investigated and compared with experimental results.

Spectroscopic analysis of Tm(3+) in PbO-Bi(2)O(3)-Ga(2)O(3) glass.

Tm(3+)-doped heavy metal oxide glasses in the PbO-Bi(2)O(3)-Ga(2)O(3) system were prepared, and their emission characteristics were examined. Three emission bands at the infrared wavelength region were observed, at 1.46, 1.79, and 2.36 µm, which are associated with the (3)H(4) ? (3)F(4), (3)F(4) ? (3)H(6), and (3)H(4) ? (3)H(5), transitions, respectively. Measured fluorescence lifetimes for the first two transitions were 0.160 and 1.035 ms, respectively. Oscillator strengths and intensity parameters suggest that the ionicity of Tm-Obonds in the glass is higher when compared with those in other oxide glass hosts. Higher radiative transition probabilities of the three infrared emissions than those calculated for other glasses appear to provide potentials for future laser applications.