TY - JOUR
T1 - Optomechanical System Design for Dual-Mode Stand-Off Submillimeter Wavelength Imagers
AU - Gandini, Erio
AU - Svedin, Jan
AU - Bryllert, Thomas
AU - Llombart Juan, Nuria
PY - 2017/5/16
Y1 - 2017/5/16
N2 - In this paper, the practical tradeoffs for designing submillimeter wavelength imagers based on optomechanical systems combined with focal plane arrays (FPAs) are presented. The architecture of these systems differs for operation at short and long ranges. General formulas to derive the effective field of view of diffraction limited quasi-optical systems in these two scenarios are shown. These formulas can be used to evaluate the performance of a specific optical system implementation. As an application example, we present the design of an optomechanical system that can operate at both ranges in a modular approach. The presented implementation achieves an effective field of view, which is 70% of the canonical one. The proposed solution consists of a linear FPA of eight active transceivers combined with a raster scan technique. The system for short-range scenario is a side-fed dual-reflector Dragonian architecture because of its good scanning performance when illuminated by an FPA. Thanks to the system's small aperture, the scanner is arranged after the primary mirror, without causing additional scan loss. The Dragonian system is then used to illuminate a confocal dual-reflector architecture to magnify its aperture, and can be used in the long-range scenario. The scanner in this case is before the main aperture and it has to be considered in the performance optimization of the optical system since it adds phase aberration loss.
AB - In this paper, the practical tradeoffs for designing submillimeter wavelength imagers based on optomechanical systems combined with focal plane arrays (FPAs) are presented. The architecture of these systems differs for operation at short and long ranges. General formulas to derive the effective field of view of diffraction limited quasi-optical systems in these two scenarios are shown. These formulas can be used to evaluate the performance of a specific optical system implementation. As an application example, we present the design of an optomechanical system that can operate at both ranges in a modular approach. The presented implementation achieves an effective field of view, which is 70% of the canonical one. The proposed solution consists of a linear FPA of eight active transceivers combined with a raster scan technique. The system for short-range scenario is a side-fed dual-reflector Dragonian architecture because of its good scanning performance when illuminated by an FPA. Thanks to the system's small aperture, the scanner is arranged after the primary mirror, without causing additional scan loss. The Dragonian system is then used to illuminate a confocal dual-reflector architecture to magnify its aperture, and can be used in the long-range scenario. The scanner in this case is before the main aperture and it has to be considered in the performance optimization of the optical system since it adds phase aberration loss.
KW - Concealed object detection
KW - imaging system
KW - optomechanical system
KW - quasi-optical system
KW - security
KW - stand-off detection
KW - submillimeter wavelength
UR - http://www.scopus.com/inward/record.url?scp=85019923623&partnerID=8YFLogxK
UR - http://resolver.tudelft.nl/uuid:ed6cfdc9-d69d-4fef-97d5-fb56ce5374c5
U2 - 10.1109/TTHZ.2017.2700759
DO - 10.1109/TTHZ.2017.2700759
M3 - Article
AN - SCOPUS:85019923623
SN - 2156-342X
VL - 7
SP - 393
EP - 403
JO - IEEE Transactions on Terahertz Science and Technology
JF - IEEE Transactions on Terahertz Science and Technology
IS - 4
M1 - 7929367
ER -