Investigations on Practical Issues in Solid Immersion Lens Based Sub-Wavelength Terahertz Imaging Technique: System Stability Verification and Interference Pattern Removal

Terahertz (THz) imaging techniques are attractive for a wide range of applications, such as non-destructive testing, biological sensing, and security imaging. We investigate practical issues in THz imaging systems based on a solid immersion lens (SIL). The system stability in terms of longitudinal m...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Da-Hye Choi, Jun-Hwan Shin, Il-Min Lee, Kyung Hyun Park
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	terahertz sub-wavelength imaging interference pattern removal contact-free measurement non-destructive testing Chemical technology TP1-1185
Acceso en línea:	https://doaj.org/article/8896efcd310540cbaab266b62310b35c
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:8896efcd310540cbaab266b62310b35c
record_format	dspace
spelling	oai:doaj.org-article:8896efcd310540cbaab266b62310b35c2021-11-11T19:01:58ZInvestigations on Practical Issues in Solid Immersion Lens Based Sub-Wavelength Terahertz Imaging Technique: System Stability Verification and Interference Pattern Removal10.3390/s212169901424-8220https://doaj.org/article/8896efcd310540cbaab266b62310b35c2021-10-01T00:00:00Zhttps://www.mdpi.com/1424-8220/21/21/6990https://doaj.org/toc/1424-8220Terahertz (THz) imaging techniques are attractive for a wide range of applications, such as non-destructive testing, biological sensing, and security imaging. We investigate practical issues in THz imaging systems based on a solid immersion lens (SIL). The system stability in terms of longitudinal misalignment of the SIL is experimentally verified by showing that the diffraction-limited sub-wavelength beam size (0.7 λ) is maintained as long as the SIL is axially located within the depth-of-focus (~13 λ) of the objective lens. The origin of the fringe patterns, which are undesirable but inevitable in THz imaging systems that use continuous waves, is analytically studied, and a method for minimizing the interference patterns is proposed. By combining two THz images obtained at different axial positions of the object and separated by λ/4, the interference patterns are significantly reduced, and the information hidden under the interference patterns is unveiled. The broad applicability of the proposed method is demonstrated by imaging objects with different surface profiles. Our work proves that the resolution of conventional THz imaging systems can easily be enhanced by simply inserting a SIL in front of the object with high tolerance in the longitudinal misalignment and provides a method enabling THz imaging for objects with different surface profiles.Da-Hye ChoiJun-Hwan ShinIl-Min LeeKyung Hyun ParkMDPI AGarticleterahertzsub-wavelength imaginginterference pattern removalcontact-free measurementnon-destructive testingChemical technologyTP1-1185ENSensors, Vol 21, Iss 6990, p 6990 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	terahertz sub-wavelength imaging interference pattern removal contact-free measurement non-destructive testing Chemical technology TP1-1185
spellingShingle	terahertz sub-wavelength imaging interference pattern removal contact-free measurement non-destructive testing Chemical technology TP1-1185 Da-Hye Choi Jun-Hwan Shin Il-Min Lee Kyung Hyun Park Investigations on Practical Issues in Solid Immersion Lens Based Sub-Wavelength Terahertz Imaging Technique: System Stability Verification and Interference Pattern Removal
description	Terahertz (THz) imaging techniques are attractive for a wide range of applications, such as non-destructive testing, biological sensing, and security imaging. We investigate practical issues in THz imaging systems based on a solid immersion lens (SIL). The system stability in terms of longitudinal misalignment of the SIL is experimentally verified by showing that the diffraction-limited sub-wavelength beam size (0.7 λ) is maintained as long as the SIL is axially located within the depth-of-focus (~13 λ) of the objective lens. The origin of the fringe patterns, which are undesirable but inevitable in THz imaging systems that use continuous waves, is analytically studied, and a method for minimizing the interference patterns is proposed. By combining two THz images obtained at different axial positions of the object and separated by λ/4, the interference patterns are significantly reduced, and the information hidden under the interference patterns is unveiled. The broad applicability of the proposed method is demonstrated by imaging objects with different surface profiles. Our work proves that the resolution of conventional THz imaging systems can easily be enhanced by simply inserting a SIL in front of the object with high tolerance in the longitudinal misalignment and provides a method enabling THz imaging for objects with different surface profiles.
format	article
author	Da-Hye Choi Jun-Hwan Shin Il-Min Lee Kyung Hyun Park
author_facet	Da-Hye Choi Jun-Hwan Shin Il-Min Lee Kyung Hyun Park
author_sort	Da-Hye Choi
title	Investigations on Practical Issues in Solid Immersion Lens Based Sub-Wavelength Terahertz Imaging Technique: System Stability Verification and Interference Pattern Removal
title_short	Investigations on Practical Issues in Solid Immersion Lens Based Sub-Wavelength Terahertz Imaging Technique: System Stability Verification and Interference Pattern Removal
title_full	Investigations on Practical Issues in Solid Immersion Lens Based Sub-Wavelength Terahertz Imaging Technique: System Stability Verification and Interference Pattern Removal
title_fullStr	Investigations on Practical Issues in Solid Immersion Lens Based Sub-Wavelength Terahertz Imaging Technique: System Stability Verification and Interference Pattern Removal
title_full_unstemmed	Investigations on Practical Issues in Solid Immersion Lens Based Sub-Wavelength Terahertz Imaging Technique: System Stability Verification and Interference Pattern Removal
title_sort	investigations on practical issues in solid immersion lens based sub-wavelength terahertz imaging technique: system stability verification and interference pattern removal
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/8896efcd310540cbaab266b62310b35c
work_keys_str_mv	AT dahyechoi investigationsonpracticalissuesinsolidimmersionlensbasedsubwavelengthterahertzimagingtechniquesystemstabilityverificationandinterferencepatternremoval AT junhwanshin investigationsonpracticalissuesinsolidimmersionlensbasedsubwavelengthterahertzimagingtechniquesystemstabilityverificationandinterferencepatternremoval AT ilminlee investigationsonpracticalissuesinsolidimmersionlensbasedsubwavelengthterahertzimagingtechniquesystemstabilityverificationandinterferencepatternremoval AT kyunghyunpark investigationsonpracticalissuesinsolidimmersionlensbasedsubwavelengthterahertzimagingtechniquesystemstabilityverificationandinterferencepatternremoval
_version_	1718431657508208640

Investigations on Practical Issues in Solid Immersion Lens Based Sub-Wavelength Terahertz Imaging Technique: System Stability Verification and Interference Pattern Removal

Ejemplares similares