Abstract
Real-time terahertz (THz) imaging offers remarkable application possibilities, especially in the security and medical fields. However, most THz detectors work with scanners, and a long image acquisition time is required. Some thermal detectors can achieve real-time imaging by using a focal plane array but have the drawbacks of low sensitivity due to a lack of suitable absorbing materials. In this study, we propose a novel photomechanical meta-molecule array by conveniently assembling THz meta-atom absorbers and bi-material cantilevers together, which can couple THz radiation to a mechanical deflection of the meta-molecules with high efficiency. By optically reading out the mechanical deflections of all of the meta-molecules simultaneously, real-time THz imaging can be achieved. A polyimide sacrificial layer technique was developed to fabricate the device on a glass wafer, which facilitates the transmission of a readout light while the THz wave radiates onto the meta-molecule array directly from the front side. THz images and video of various objects as well as infrared images of the human body were captured successfully with the fabricated meta-molecule array. The proposed photomechanical device holds promise in applications in single and broadband THz as well as infrared imaging.
Highlights
Terahertz (THz) imaging has received substantial attention and has become a highly active field over the past two decades, owing to the unique properties of THz waves, leading to promising applications in numerous fields, including security screening, medical imaging, and remote sensing[1,2,3]
Most available THz imaging systems operate in the scan mode by using the above-mentioned photonic or thermal detectors, which may require between tens of seconds and several hours to obtain one image[14,15]
Because the thermomechanical sensitivity presents the relation of ST∝Lb2i × (α1 − α2), where Lbi is the length of the bi-material cantilever and α1 and α2 are the thermal coefficients of expansion (TCE) for the two materials, it can be seen that a large TCE difference and a long bi-material cantilever length would increase the thermomechanical sensitivity
Summary
Terahertz (THz) imaging has received substantial attention and has become a highly active field over the past two decades, owing to the unique properties of THz waves, leading to promising applications in numerous fields, including security screening, medical imaging, and remote sensing[1,2,3]. Despite the high sensitivity and extremely fast response time, the sensible band of most photonic detectors is narrow, and their typical requirement of cryogenic cooling systems causes them to be expensive and bulky[9,10,11]. The thermal detector absorbs the THz radiation as heat, which generates measurable output signals induced by the temperature-related changes in material properties. Most available THz imaging systems operate in the scan mode by using the above-mentioned photonic or thermal detectors, which may require between tens of seconds and several hours to obtain one image[14,15]. A modified infrared microbolometer-based focal plane array has preliminarily been demonstrated in real-time THz imaging applications and requires only tens of microseconds to shoot one THz image[16]; its sensitivity suffers considerably because of the lack of suitable THz-absorbing materials
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
