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We present technological bricks and concepts under study which could permit build up of future THz remote sensing systems. Critical issues regarding such systems mainly rely on the availability of sensitive and compact detectors together with powerful and versatile sources. Potential use of plasma waves in nano-transistor is presented which can be exploited for the realization of an efficient mixer...
In the last few years, the interaction of terahertz (THz) radiation with many-electron systems in semiconductors, metals, graphene, or other materials has attracted significant attention worldwide. After our original suggestion to used THz radiation to identify excitonic populations in semiconductors, our group proceeded to developed a microscopic many-body approach that allows us to quantitatively...
Designing an automatic phase matching device for a surface emitted terahertz-wave (THz) parametric oscillator and a THz-wave detection unit using parametric up-conversion in MgO:LiNbO3, we realized a frequency-agile, monochromatic THz-wave generation and detection system.
We present results on the generation of tunable continuous-wave THz radiation via photomixing on a PCA using a dual mode external cavity diode laser (2??-ECDL). The tuning range reaches from 250 GHz up to several THz.
Wave-mixing at 370-GHz in a SOA and FP semiconductor laser is investigated by using a FROG-system. A comparison of the optical time-fluctuations measured at their output stresses the importance of a resonant cavity in THz-signals generation from semiconductor optical devices.
We present a scheme for dual-wavelength operation of a diode-pumped Cr3+:LiCaAlF6 (Cr3+:LiCAF) laser with tunable frequency difference based on external optical feedback from a Littman-mounted diffraction grating. The maximum spectral separation achieved allows a frequency separation from 0 to 9 THz in the 785 nm region.
The authors demonstrate a novel tuning mechanism based on the unique feature of an unusual device termed "wire laser", which is defined as a laser whose dimension in the transverse direction w is much smaller than ??. As such, a large fraction of the mode propagates outside the solid core. Placing a movable object close to the wire laser allows direct manipulation of the evanescent laser...
In recent years, considerable effort has been made to enhance the overall performance of quantum cascade lasers (QCLs). One of the main is their room temperature operation. With the increase of the Boltzmann Energy k.T, processes like thermal backfilling of the lower laser states become more likely. Furthermore scattering processes like roughness scattering or stimulated LO phonon emission increase...
Terahertz quantum cascade lasers (THz QCLs) are currently the most advanced semiconductor lasers in the spectral range 1–5 THz. However, their operation is still limited to cryogenic temperatures with the highest operating temperature (Tmax) of 186K demonstrated for devices based on the single-resonant-phonon design [1]. The factors that may be limiting the temperature performance of these devices...
We present the design and realization of active photonic crystal (PhC) terahertz quantum-cascade lasers. The PhC consists of isolated pillars which are fabricated from the laser gain region. A stable single mode operation under all driving conditions is achieved.
Development and application of real-time (> 5Hz) first-surface and bulk reflection measurements using the mini-Z THz time-domain-spectrometer (TDS) are presented for standoff detection and identification of organic, pharmaceutical and energetic compounds. A non-iterative baseline correction for scattering is applied to real-time data to expand THz sensing across a wider range of sample preparation...
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