We demonstrate a tomographic imaging modality that uses pulsed terahertz (THz) radiation to probe the optical properties of three-dimensional (3D) structures in the far-infrared. This THz-wave computed tomography (T-ray CT) system provides sectional images of objects in a manner analogous to conventional CT techniques such as x-ray CT. The transmitted amplitude and phase of broadband pulses of ...

Optical antennas interface an object with optical radiation and boost the absorption and emission of light by the objects through the antenna modes. It has been much desired to enhance both excitation and emission processes of the quantum emitters as well as to interface multiwavelength channels for many nano-optical applications. Here we report the experimental implementation of an optical ant...

Background: Similar to the thermoluminescence (TL) spectra, the optical parameters variations can also be used in TL crystals for dosimetry purposes. These optical parameters can include absorption, transmission and reflection coefficients. Materials and Methods: Single crystals of KBr and KCl which have been used in this research were grown from laboratory grade extra pure precursor p...

A novel scheme for the optical generation and coherent detection of tunable narrow-band far-infrared radiation in free space is described. This technique involves the optical heterodyning of two linearly chirped broadband pulses to produce a quasi-sinusoidal intensity modulation at tunable terahertz frequencies. The frequency content of the narrow-band terahertz radiation produced by mixing chi...

A secondary optimization technique was proposed to estimate the temperature-dependent thermal conductivity and absorption coefficient. In the proposed method, the stochastic particle swarm optimization was applied to solve the inverse problem. The coupled radiation and conduction problem was solved in a 1D absorbing, emitting, but non-scattering slab exposed to a pulse laser. It is found that i...

Suitably designed optical fibers are shown to offer a powerful tool for functional brain mapping, facilitating the detection of Cherenkov radiation generated by relativistic positrons from positron-emitting radionuclides. Fiber probes support a low-loss delivery of the high-intensity short-wavelength part of the Cherenkov spectrum, which is strongly absorbed by biotissues, and lower the thresho...

patients receiving diagnostic doses of radiopharmaceuticals become a source of contamination and exposure for those who come in contact with them, such as nuclear medicine technologists, relatives and nurses. therefore, the measurement of external radiation dose from these patients is necessary. in this study, the dose rates at distances of 10, 50 and 100cm from 70 patients who received diagnos...