Share Email Print
cover

Proceedings Paper

Developments in quasi-optical design for THz
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Optical design in the terahertz (THz) waveband suffers from a lack of dedicated software tools for modelling the range of electromagnetic and quasi-optical propagation conditions encountered in typical systems. Optical engineers are forced to use packages written for very different wavelength systems and there is often a lack of confidence in the results because of possible inappropriate underlying physical models. In this paper we describe the analytical techniques and dedicated CAD software tools (MODAL) that we are developing for long-wavelength design and analysis in the THz waveband. Our basic approach to modelling long-wavelength propagation is the application of modal analysis appropriate to the problem under investigation. We have extended this to include the efficient description of common off-axis (tilted) components such as simple curved reflectors. In earlier research we have investigated the conditions under which approximate methods (ray tracing, paraxial modes) can provide extremely efficient and accurate solutions and situations where a more rigorous approach is required. As a rigorous model of electromagnetic wave propagation, physical optics can be used to characterize complete systems to high accuracy. However, the straightforward approach is computationally intensive and, therefore, not suitable for the initial design or preliminary analysis of large multi-element optical systems. In order to improve the computational efficiency of the usual PO approach we have developed fast physical optics software, initially for the analysis of the ESA PLANCK system. The MODAL code is modular and multi-platform, and different propagation models can be used within the same framework. Distributed parallel computing enables significant reduction of the time needed to perform the calculations. We present the new software and analyses of the QuaD and Herschel (HIFI) telescope systems.

Paper Details

Date Published: 8 October 2004
PDF: 12 pages
Proc. SPIE 5498, Millimeter and Submillimeter Detectors for Astronomy II, (8 October 2004); doi: 10.1117/12.551660
Show Author Affiliations
Creidhe O'Sullivan, National Univ. of Ireland/Maynooth (Ireland)
J. Anthony Murphy, National Univ. of Ireland/Maynooth (Ireland)
Gary Cahill, National Univ. of Ireland/Maynooth (Ireland)
Marcin Lukasz Gradziel, National Univ. of Ireland/Maynooth (Ireland)
Neil Trappe, National Univ. of Ireland/Maynooth (Ireland)
David White, National Univ. of Ireland/Maynooth (Ireland)
Institute of Technology Tallaght (Ireland)
Vladimir Yurchenko, National Univ. of Ireland/Maynooth (Ireland)
Stafford Withington, Univ. of Cambridge (United Kingdom)
Willem Jellema, Space Research Organization of the Netherlands (Netherlands)


Published in SPIE Proceedings Vol. 5498:
Millimeter and Submillimeter Detectors for Astronomy II
Jonas Zmuidzinas; Wayne S. Holland; Stafford Withington, Editor(s)

© SPIE. Terms of Use
Back to Top