We present a numerical study of electromagnetic wave transport in disordered quasi– one-dimensional waveguides at terahertz frequencies. Finite element method calculations of terahertz wave propagation within LiNbO3 waveguides with randomly arranged air-filled circular scatterers exhibit an onset of Anderson localization at experimentally accessible length scales. Results for the average transm...

Spectroscopic techniques combined with chemometrics methods have proven to be effective tools for the discrimination of objects with similar properties. In this work, terahertz time-domain spectroscopy (THz-TDS) combined with discriminate analysis (DA) and principal component analysis (PCA) with derivative pretreatments was performed to differentiate transgenic rice (Hua Hui 1, containing the C...

A novel terahertz plasma-wave photomixer that can improve the conversion gain and terahertz radiation power is proposed and evaluated. The photomixer is based on a high-electron mobility transistor and incorporates doubly interdigitated grating strips for the gate electrodes that periodically localize the 2D plasmons in 100-nm regions with a micron-order interval. A vertical cavity structure is...

The elegant concept of Nanocommunication at terahertz (THz) frequency is proposed with its main focus on investigating electromagnetic material properties of synthesized Dermis layer of the skin via THz-Time Domain Spectroscopy (TDS). The paper highlights the study of human skin and cell culture. Methods are applied to synthesize collagen and measurements are carried out in the THz band ranging...

We report the realization of coherent electro-optical detection of nanosecond terahertz (THz) pulses from an optical parametric oscillator, which is pumped by a Q-switched nanosecond Nd:YVO4 laser at 1064 nm and emits at approximately 1.5 THz. The beam profile and wavefront of the THz beam at focus are electro-optically characterized toward the realization of a real-time THz camera. A peak dyna...

We report the study of femtosecond laser-induced air plasma fluorescence under the illumination of terahertz (THz) pulses. Semiclassical modeling and experimental verification indicate that time-resolved THz radiation-enhanced emission of fluorescence is dominated by the electron kinetics and the electron-impact excitation of gas molecules or ions. We demonstrate that the temporal waveform of t...

We report the measurement of optically rectified terahertz (THz) wave power relative to the optical excitation area. Rectified THz wave power reaches its maximum when radius r of the optical excitation area is comparable to the center wavelength of the rectified THz radiation. When r is smaller than the center wavelength of the rectified THz radiation, an r(2) relationship is demonstrated. A mo...

In recent years, terahertz radiation sources are increasingly being exploited in military and civil applications. However, only a few studies have so far been conducted to examine the biological effects associated with terahertz radiation. In this study, we evaluated the cellular response of mesenchymal mouse stem cells exposed to THz radiation. We apply low-power radiation from both a pulsed b...

The Submillimeter-Wave Technology Laboratory (STL) at the University of Massachusetts Lowell has designed and constructed two high resolution terahertz imaging systems based on 325 GHz and 1.5 THz transceivers. While the systems were originally designed to acquire radar signatures of high fidelity scale models, their high sensitivity and high stability at 325 GHz and 1.5 THz make them novel sys...

The generation of terahertz (THz) transients in photoconductive emitters has been studied by varying the spatial extent and density of the optically excited photocarriers in asymmetrically excited, biased low-temperature-grown GaAs antenna structures. We find a pronounced dependence of the THz pulse intensity and broadband (>6.0 THz) spectral distribution on the pump excitation density and simu...