Research on exploring millimeter waves and/or terahertz (THz) waves, which cover the frequency range from 30 GHz to 10 THz, has lately increased since the nature of these electromagnetic waves is suited to spectroscopic sensing as well as to ultra-broadband wireless communications. One of the obstacles to developing applications of millimeter waves and terahertz waves is a lack of solid-state s...

A freely tunable polarization rotator for broadband terahertz waves is demonstrated using a three-rotating-layer metallic grating structure, which can conveniently rotate the polarization of a linearly polarized terahertz wave to any desired direction with nearly perfect conversion efficiency. This low-cost, high-efficiency, and freely tunable device has potential applications as material analy...

The terahertz (THz) band of the electromagnetic spectrum, with frequencies ranging from 300 GHz to 3 THz, has attracted wide interest in recent years owing to its potential applications in numerous areas. Significant progress has been made toward the development of devices capable of actively controlling terahertz waves; nonetheless, further advances in device functionality are necessary for em...

A new electro-optic (EO) sampling scheme, which we refer to as "heterodyne EO sampling", for detection of pulsed terahertz (THz) waves is proposed and experimentally demonstrated. In this heterodyne EO sampling scheme, the intensity change in the optical probe pulse induced by a THz field in a nonlinear crystal is measured without any polarization optics. Applied in combination with the non-col...

The paper presents the initial results of the epoxy-glass composite samples analyses carried out with the use of terahertz spectroscopy. Firstly, the standard specimens made of epoxy resin and glass fibers were researched. The first sample consisted of one layer of glass fiber, the second one had two such layers. To compare the results the results of the composite material sample shut with the ...

It is crucial to understand the various biological effects induced by terahertz (THz) electromagnetic waves with the rapid development of electronic and photonic devices operating in the THz frequency region. The presence of sweat glands plays an important role in THz wave interactions with human skin. We investigated the morphological features of sweat ducts using optical coherence tomography ...

3D printing opens up an inexpensive, rapid, and versatile path to the fabrication of optical elements suited to the terahertz regime. The transmission of the plastics used in 3D printers, while generally decreasing with frequency, is usable over the range 0.1-2 THz. We have designed, fabricated, and tested regular and blazed gratings and aspherical lenses for operation at terahertz frequencies....

A system of two probes is designed for terahertz (THz) time-domain spectroscopy of sub-wavelength size objects. A twin-needle probe confines broadband THz pulses spatially by means of surface plasmon waves to a sub-wavelength spot smaller than 10 microns. The confined pulses are detected within the near-field zone of the twin-needle probe by a sub-wavelength aperture probe. The system allows TH...

Osteoarthritis (OA) is a common form of arthritis caused by cartilage degeneration. In this paper, we investigate the potential use of terahertz (THz) pulsed imaging to quantitatively measure the early symptoms of OA in an animal model. THz images of excised rabbit femoral condyles were taken. We observe THz waves reflected off different layers within samples and demonstrate that the optical de...

Terahertz (THz) and metamaterials are both hot topics in electromagnetics research. The THz band (0.1-10 THz) lies in the ‘gap’ between microwave and far infrared regions. Research is currently underway to characterize how these waves interact with matter, with potential applications including security screening, medical imaging, and non-destructive evaluation. Metamaterials are artificial mate...