Results 131 to 140 of about 5,729,346 (195)

Increasing the diffraction losses in gyrotron beam tunnels for improved suppression of parasitic oscillations

International Conference on Infrared, Millimeter, and Terahertz Waves, 2019
High-power gyrotrons often suffer from parasitic oscillations in the compression region (beam tunnel) prior to the interaction cavity. A possible way to suppress the parasitic oscillations is to raise their starting currents by increasing the losses of ...
Ioannis G. Chelis, Dimitrios Peponis, G. Latsas, I. Tigelis   +3 more
semanticscholar   +1 more source

VCSEL diffraction-loss theory

IEE Proceedings - Optoelectronics, 1995
Mode matching in the Fourier spectral domain is used to obtain an expression for the reflectivity between the active cavity and the Bragg mirror of a mesa-geometry VCSEL. The variation of incident mode reflectivity with various parameters is discussed.
R.R. Burton, P.N. Robson, P.C. Kendall, M.S. Stern   +3 more
openaire   +1 more source

Low-Loss Open Resonators and Diffraction Formulas

Applied Optics, 1972
Si descrive una procedura basata su un "nucleo iterato n-volte" per valutare numericamente modi e perdite di risonatori aperti con perdite dell'odine di un millesimo o inferiori. Si è applicata la procedura a un risonatore flat-roof con numero di Fresnel N=12.25 e trovato un grande vantaggio nel tempo di elaborazione per esempio con un nucleo iterato ...
A. Consortini, F. Pasqualetti
openaire   +3 more sources

Diffraction loss of confined modes in microcavities

1997 Digest of the IEEE/LEOS Summer Topical Meeting: Vertical-Cavity Lasers/Technologies for a Global Information Infrastructure/WDM Components Technology/Advanced Semiconductor Lasers and Applications/Gallium Nitride Materials, Processing, and Devices (C, 2002
In this paper, the loss of a simplified cavity is studied using an accurate numerical model that solves the scalar Helmholtz Equation at each point in the cavity. The idealized cavity geometry consists of two perfect mirrors. The upper mirror is offset inward at some radius as shown, so that the cavity is laterally index guided.
G.R. Hadley, K.L. Lear
openaire   +1 more source

On the Diffraction Loss of Optical Resonator

Japanese Journal of Applied Physics, 1966
The oscillation characteristics are reported of a helium-neon laser equipped with a resonator which consists of two concave spherical reflectors with non-identical curvatures. Laser oscillations in resonator arrangements of the so-called high loss geometry are studied. The powers and the field patterns of the output beam are shown.
Ryuichi Hioki, Takeomi Suzuki
openaire   +1 more source

Diffractional losses in corner reflectors

Proceedings of LFNM 2005. 7th International Conference on Laser and Fiber-Optical Networks Modeling, 2005., 2005
We present the analysis of fundamental losses of optical power in dielectrical corner reflectors, which are now planned to replace spherical mirrors in the next generation of large-scale Earth-based gravitational wave detectors. The mechanism of losses is diffractional scattering of light beam used in Fabry-Perot resonator on the edge of corner ...
openaire   +1 more source

A Low-Loss Diffraction Grating Frequency Multiplexer

IEEE Transactions on Microwave Theory and Techniques, 1978
A quasi-optical frequency multiplexer based on a blazed diffraction grating is studied. Experimental data, supported by semi-quantitative theoretical considerations, show that the multiplexer is an efficient channel-dropping filter well suited to use in the millimeter wave region.
P.S. Henry, J.T. Ruscio
openaire   +1 more source

Relativistic effects in core-loss electron diffraction

Physical Review B, 2006
We present experimental evidence of relativistic fine structure in inelastic electron diffraction patterns of a crystalline solid at zone-axis orientation. Diffraction patterns formed by 200 keV electrons suffering energy losses within 10 eV of the silicon K-ionization edge at zone axis exhibit excellent agreement with a relativistic theory of atomic
Christian Dwyer, Jonathan S. Barnard
openaire   +1 more source

Quantification of crystallinity using zero‐loss filtered electron diffraction

Microscopy Research and Technique, 2018
AbstractThe quantity of the crystalline phases present in a nanomaterial is an important parameter that governs the correlation between its properties and microstructure. However, quantification of crystallinity in nanoscale‐level applications by conventional methods (Raman spectroscopy and X‐ray diffraction) is difficult because of the spatial ...
Byeong‐Seon An, Yena Kwon, Hyun‐Woo Cha, Min‐Chul Kang, Jin‐Su Oh, Cheol‐Woong Yang   +5 more
openaire   +2 more sources

Experimental investigation of diffraction losses on radio links

IEEE Antennas and Propagation Society International Symposium 1997. Digest, 2002
The requirement for the calculation of microwave link path loss has received considerable attention over time and a number of path loss prediction algorithms have been created. Many of these however are based on theoretical calculations using idealized obstacles so that the actual measured path loss will deviate significantly from calculated values ...
R.G. Mazzolin, J.S. Dahele
openaire   +1 more source