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Terahertz (THz) time-domain transmission spectroscopy was used to obtain the absorption coefficients and refractive indices of silica, Pyrex, and seven different Schott glasses. The refractive indices were analyzed using the Clausius–Mossotti equation, and the absorption coefficients in terms of the power-law model of far-infrared absorption. Relationships were observed between THz absorption and refractive indices on the one hand, and glass properties on the other. THz transmission data have been shown to provide a useful insight into glass structure. [ABSTRACT FROM AUTHOR]

Analyzes the hypersensitive phosphorus and fluoride transition of praseodymium ion in fluoride glasses. Important concerns in rear-earth doped glasses; Details of the experiment conducted; Emission spectra of hypersensitive transitions.

Presents a fluoroaluminate glasses developed as hosts for neodymium-doped fiber amplifier. Need for optical amplifiers in telecommunications; Experimental details; Viscosity and crystallization in fluoroaluminate glasses.

High optical quality centimeter sized GaS crystals are grown using a modified vertical Bridgman method with heat field rotation of the growth melt. Ordinary and extraordinary wave refractive index dispersions are studied by THz time-domain spectroscopy (THz-TDS). New dispersion equations are designed to be suitable for estimating dispersion properties of solid solution GaSe1-xSx crystals from the near IR through the mid-IR and further into the THz range. [ABSTRACT FROM AUTHOR]

The design and performance of a simple and compact far-infrared Fourier transform spectrometer is described. The spectrometer works as a Michelson interferometer without a beam splitter, and uses a Golay cell or a pyroelectric sensor for detection. A pair of flat lamellar mirrors with a computer-controlled displacement introduces a precisely defined phase difference between two parallel beams of nearly equal radiated power. The interferometer is intended for operation at frequencies between 0.1 and 3 THz with a frequency resolution of 6 GHz, and is used to characterize both continuous-wave and pulsed terahertz emitters, as well as different terahertz detectors. [ABSTRACT FROM PUBLISHER]

Superposition of orbital eigenstates is crucial to quantum technology utilizing atoms, such as atomic clocks and quantum computers, and control over the interaction between atoms and their neighbours is an essential ingredient for both gating and readout. The simplest coherent wavefunction control uses a two-eigenstate admixture, but more control over the spatial distribution of the wavefunction can be obtained by increasing the number of states in the wavepacket. Here we demonstrate THz laser pulse control of Si:P orbitals using multiple orbital state admixtures, observing beat patterns produced by Zeeman splitting. The beats are an observable signature of the ability to control the path of the electron, which implies we can now control the strength and duration of the interaction of the atom with different neighbours. This could simplify surface code networks which require spatially controlled interaction between atoms, and we propose an architecture that might take advantage of this. [ABSTRACT FROM AUTHOR]

The accurate measurement of the permittivity, loss tangent and dielectric anisotropy DC bias dependence for two different liquid crystal (LC) materials in the frequency range 140-165 GHz is described. The electrical characteristics are obtained by curve fitting computed transmission coefficients to the experimental spectral response of a new class of electronically reconfigurable frequency selective surface. The periodic structure is designed to yield bandpass filter characteristics with and without an applied bias control voltage in order to measure the tunability of the LC material which is inserted in a 705 µm-thick cavity. [ABSTRACT FROM AUTHOR]

A method to quantify the linearity and dynamic range of terahertz detectors is reported and used to show that terahertz time-domain-spectrometers exhibit a nonlinear amplitude response at frequencies below 1.5 THz. [ABSTRACT FROM AUTHOR]

A simple scheme for generating continuous-wave (CW) terahertz (THz) radiation from a two-colour laser is reported. A Ti-sapphire laser is forced to oscillate on two modes by placing a Fabry-Perot etalon in the laser cavity. THz radiation is generated by photomixing in a biased photoconverter. The THz frequency is determined by the separation of the etalon plates. [ABSTRACT FROM AUTHOR]