One-kilojoule pulsed-power generator for laboratory space sciences.

This paper reports on the assembly of a compact, low-cost, pulsed-power facility used for plasma studies. The construction uses two modules placed on opposite sides of the test chamber to minimize the system impedance and improve access to test samples. The stored energy is 1  kJ with a peak current of 135  kA and a 1592  ns quarter-period time. Up until now, an imploding conical-wire array has been studied by using time-integrated (visible) imaging, and time-resolved laser imaging, providing a measure of the plasma jet speed in the range of 170  km/s. Our future plans will continue to investigate high-energy-density plasmas that are relevant to the space environment, fusion, and spectroscopy.

Gain-guided index-antiguided fiber with a Fabry-Perot layer for large mode area laser amplifiers.

We propose a modified gain-guided index-antiguided (GGIAG) fiber structure for large mode area laser amplifiers, in which a thin dielectric layer is placed between the low-index core and the high-index cladding. The introduced dielectric layer functions as a Fabry-Perot etalon. By letting the resonant wavelength of the Fabry-Perot layer coincide with the signal wavelength, the signal is gain-guided in the fiber core. Moreover, the pump is confined in the low-index core owing to the antiresonant reflection originated from the Fabry-Perot layer. Numerical results indicate that the leakage loss of the pump can be minified over two orders of magnitude in the proposed structure, and thus the end-pumping efficiency could be enhanced significantly.

Arbitrary-order interface conditions for slab structures and their applications in waveguide analysis.

We extend the continuity relations of field derivatives across an abrupt interface to arbitrary orders for transverse electric and magnetic waves in slab structures. Higher-order finite-difference formulation is then obtained by combining the systematically-obtained interface conditions with Taylor series expansion. Generalized Douglas scheme is also adopted to further enhance the convergence of truncation errors by two orders. We apply the derived finite-difference formulation, up to nine-points in this paper, to solve the guided modes in simple a slab waveguide and multiple quantum well waveguides. The results shows the truncation error is much higher, up to tenth order, as expected. Using those higher-order schemes, accurate results are obtained with much fewer sampled points, and hence with tremendously less computation time and memory.