thz imaging
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AbstractWe discuss the progress in the field of THz imaging based on time-domain spectroscopy during the last 20 years emphasizing several highlights. These include 3D mapping of the water distribution of plants, THz reflection imaging of samples with arbitrary shape, burn wound imaging and the early diagnosis of diabetic foot disease. These applications greatly benefit from the introduction of fibre-coupled THz time-domain system operated by rugged and portable femtosecond fibre-lasers. THz imaging is a versatile measurement method that has a plethora of practical applications and great promise for the future.

Terahertz (THz) radiation is one of the new, intensively studied interdisciplinary fi elds of scientifi c knowledge, including medicine, in the fi rst decades of the 21st century. At the beginning of this article (review), in a brief form, the basic statements on THz radiation, the main parameters and properties are presented; the modern THz biophtonics technologies used in biology and medicine are considered – THz refl ectometry, THz spectroscopy methods. Then a number of directions and examples of possible use of THz technologies in biology and medicine, including pharmaceuticals, are given. The main part of the review presents the progress of experimental research and the prospects for the clinical application of medical technologies of THz spectroscopy, THz imaging, in ophthalmology in the study of the morphological and functional state of the ocular surface structures, diagnosis, medical testing, and treatment of ophthalmopathology of the ocular surface. The article concludes with a review of experimental studies on the safety of using THz waves for medical diagnostics and treatment of ophthalmopathology. In the fi nal part, the main problems and prospects of introducing medical THz technologies into the clinical practice of an ophthalmologist are considered.

As technology advances, notable scientific research accomplishments have been made. Terahertz (THz) waves have been seen to have endless potential applications that could further improve the current limitations of other frequency bands for imaging applications. Currently, THz waves display great potential in various applications due to their noninvasive and nonionizing features. However, the THz band has not been technically well established. This paper focuses on a comparative survey of the current methods applied in THz imaging in the field of medical and industrial security applications. Different types of methods, findings, advantages, and challenges of surveys ranging from 2016 to 2021 were discussed for both medical and industrial security applications to deepen the understanding of the latest trends, research, and technologies to have efficient THz imaging systems.

Abstract Recently there has been an increasing demand for terahertz technology especially in imaging. In the past few decades, the applications of terahertz (THz) imaging technology have seen significant developments in the fields of biology, medical diagnosis, food safety, and nondestructive testing. The medical and semiconductor industry has always attracted significant attention worldwide. In particular, the importance of real and perfect inspection technologies has been growing due to an increasing demand for improving the quality of life and developing industries. This paper presents the research of THz technology with super-resolution THz imaging in transmission mode on four types of different samples. We have reported transmission measurement at different THz frequency of each sample. The butterfly sample used super-resolution THz imaging. The THz super-resolution is obtained excellent at 1.8 THz, it is near about 1 micrometer. A good resolution images have been obtained. This new THz super-resolution techniques can apply in medical and security purposes. Further applications will be reported in coming papers.

this article, a multi-band polarization-insensitive metamaterial absorber is designed for THz imaging and EMI shielding. A unique oval-shaped structure with three circular ring-shaped resonators is proposed with a unit cell dimension of36×36×19.6μm3. The absorbance of the proposed multiband MMA is 98.57%, 90%and 99.85% at 5.58, 7.98-8.84, 11.45THz frequency respectively. Return loss is nearly the same for the changing incident and polarization angle. Therefore, this metamaterial absorber with a wide range of polarization insensitivity is found and it is also suitable for quantum RADAR Imaging, energy harvesting, and optoelectronic devices.

Abstract Terahertz (THz) technology is particularly suitable for non-destructive detection of porcelain sherd due to the unique properties of non-ionizing, high penetration, and broad-spectrum. In this paper, we investigated the reflection characteristics of the pigments and sediments for red and green porcelain sherd of Bayi kiln made in Shanxi province during the Jin Dynasty by terahertz time-domain spectroscopy (THz-TDS), obtaining the spectral responses of different components. Furthermore, Raman spectroscopy was used as a complementary technique to complete the qualitative analysis of the pigments and sediments. In addition, the reflective THz imaging was performed to visualize the pigments and sediments in different regions of the porcelain sherd, realizing the visual detection of the pattern on the surface of porcelain sherd. These results show that THz-TDS and THz-imaging can serve as effective tools for the detection and analysis of ancient Chinese porcelain.

In this study, we demonstrate an Nb5N6 terahertz (THz) detector with radio frequency (RF) choke-enhanced dipole antenna structure for 0.3 THz detection. The maximum electric field intensity of 218 V/m is obtained by optimizing the parameters of the dipole antenna with RF choke. Compared to a dipole antenna without RF choke, the electric field intensity of that with RF choke is improved by 2.6 times. The RF choke-enhanced dipole antenna-coupled Nb5N6 THz detector is fabricated and characterized. The measured maximum responsivity of the detector is 1100 V/W at 0.308 THz, and the corresponding noise equivalent power (NEP) is 6.4 × 10–12 W/Hz1/2. The measured response time of the Nb5N6 THz detector is as low as 8.46 μs. Furthermore, the Nb5N6 THz detector is applied to a homemade THz transmission imaging system for demonstrating its performance. The THz imaging results of a blade and access card show that the contrast of the blade image is sharp and the components hidden within the access card are clearly visible. This indicates that the Nb5N6 THz detector can be used in THz imaging, particularly in THz active imaging, which will have greater application prospects.