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The generation of coherent, high power TERA-MIR radiation with compact steady state sources operating at room temperature is one of the main technological challenges of the early 21st century. In this talk, I will review the most recent results on different types of sources and than focus on predictive simulations of Quantum Cascade Lasers, which are the best candidate sources for this spectral range.
Physics of plasma oscillations and basic principles of plasmonic detection of THz radiation in FET structures with 2D electron channels are discussed. Plasmonic devices are practically attractive because they are extremely fast and electrically tunable through the entire THz frequency band by changing electric potentials at metal contacts of the device.
Analytical and numerical solutions to the problem of diffractive emission of the difference-frequency radiation transmitted by a grating at the surface or on the substrate of a dual-wavelength heterolaser with the intracavity nonlinear mixing of two optical or near-infrared modes are given. The ways of increasing the THz and far-infrared emission efficiency of these Surface-Emitting Grating-Outcoupled...
Terahertz-range intracenter silicon lasers have demonstrated significant progress over past decade in expanding the frequency operation range, in manipulation of a silicon matrix as well as in lowering of optical pump threshold. While terahertz gain realized in silicon lasers has been already defined, optical losses in the active media have not been yet measured experimentally. We applied continuous...
Nonlinear dynamics of free-carriers in direct bandgap semiconductors at terahertz (THz) frequencies is studied using high power, few-cycle pulses. Techniques as Z-scan and THz-pump/THz-probe are employed to explore nonlinear interactions in both n-doped and photoexcited systems. The physical mechanism that gives rise to such interactions will be discussed in details.
We report of a easy-to-use terahertz radiation source, which combines a QCL operating at 3.1 THz with a compact, low-input-power Stirling cooler. The QCL, which is based on a two-miniband design, has been developed for high output powers and low electrical pump power. The whole system weighs less than 15 kg including cooler, power supplies etc. The peak output power is 8 mW at 3.1 THz. The applicability...
In this work, new approach to gain spectra tuning have been developed for quantum-cascade structures. The spectral tuning is based on the phase space filling effect evoked by optical driving signals inducing interband electron transitions and populating of conduction lasing subbands. For three-well THz GaAs/AlGaAs quantum-cascade structure, mathematical modeling show that gain spectra can be shifted...
Terahertz stimulated emission (4-6 THz) from optically excited group-V donors (phosphor P, antimony Sb, arsenic As, bismuth Bi) in axially compressed silicon crystal has been studied. As shown CW laser operation of P, Sb, As donors become reachable due to the laser threshold decrease induced by the stress.
We accumulated here the technique for measuring the electrodynamic constitutive parameters (the effective permittivity and permeability) for some 1D (one dimensional) metamaterials formed by the natural materials. The question of transfer form the radiofrequency band up to optical frequencies is under discussion.
THz spectroscopy was used to investigate bovine serum albumin (BSA) flexibility in conditions ranging from lyophilised BSA to dilute 10% w/w BSA solution and highly concentrated 50% w/w BSA solutions. The simulated THz spectra of dry and hydrated BSA are in good agreement with the experiments.
Terahertz anomalous dispersion and material physical properties leads to form the region with negative dielectric permittivity (DP) that is created around the polar frequency oscillations in three crystalline modifications of boron nitride will be analyzed in our report. Our analysis based on the simple quantitative criterion of existence the negative DP bands. Seven vibrations in different crystalline...
The results of development of multifunctional quasi-optical measuring system, designed to demonstrate the basic radio-measuring techniques in quasi-optical waveguide transmission line THz range It can be used as a training laboratory installation in high-school educational process for training of university students working on a degree in electronics and radio-physics method to the measurements in...
Two-dimensional model of a photoconducting emitter for the terahertz radiation excited by a femptosecond laser pulse is considered. Short-wave asymptotic formulas for electric fields of the emitter are presented. The contributions of both geometrical optics rays and effects of edges diffraction are taken into account.
A novel MEMS thermopile structure is presented, in which the thermopairs act as dipole antennas. The induced current heats the hot point of the thermopairs. The thermoelectric output voltage is proportional to the absorbed radiation power. The antenna-like feature of the device is demonstrated by the dependence of the sensitivity on the polarization. 5.58 V/W responsivity was achieved at 0.1 THz without...
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