Enhancing resolution of terahertz imaging systems below the diffraction limit

[EN]We report on resolution enhancement of sub-terahertz (THz) images by using the terajet effect. A mesoscale cuboid dielectric particle, used to establish the terajet, was placed in front of an object located at the focus of the THz beam. The object under study was based on a printed circuit board...

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Detalles Bibliográficos
Autores: Calvo Gallego, Jaime, Delgado Notario, Juan Antonio, Minin, Oleg V., Abidi, El Hadj, Ferrando-Bataller, Miguel, Fobelets, Kristel, Velázquez Pérez, Jesús Enrique, Minin, Igor V., Meziani, Yahya Moubarak
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2023
País:España
Institución:Universidad de Salamanca (USAL)
Repositorio:GREDOS. Repositorio Institucional de la Universidad de Salamanca
OAI Identifier:oai:gredos.usal.es:10366/160570
Acceso en línea:http://hdl.handle.net/10366/160570
Access Level:acceso abierto
Palabra clave:Diffraction limit
Image contrast
Terahertz detectors
Terajet effect
Terahertz imaging systems
1203 Ciencia de los ordenadores
3325 Tecnología de las Telecomunicaciones
Descripción
Sumario:[EN]We report on resolution enhancement of sub-terahertz (THz) images by using the terajet effect. A mesoscale cuboid dielectric particle, used to establish the terajet, was placed in front of an object located at the focus of the THz beam. The object under study was based on a printed circuit board (PCB) perforated with different holes with diameters ranging from 1.8 to 3.0 mm and separated from each other by a distance that varies from 0.25 to 4 mm. The sample was illuminated by a continuous wave source at a frequency of 0.3 THz and the image was obtained using a sensor based on a strained-Si Field-Effect Transistor. The image was formed pixel-by-pixel in a transmission mode configuration. A clearer image with enhanced resolution was obtained when the mesoscale cube was introduced in the optical path. The terajet effect made possible to resolve a separation between holes of around 0.5 mm (lower than the wavelength, 1mm), that is, below the diffraction limit. The method described is easy to implement, cost effective and could be used to improve the resolution of any real imaging system.