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Showing 1 to 11 of 11 for “"THz QCL"”.
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Towards terahertz dual-comb spectroscopy based on quantum cascade lasers
In this thesis, terahertz (THz) laser frequency combs are improved and THz dual-comb spectroscopy method is demonstrated. To achieve better performance of THz quantum cascade laser (QCL) frequency combs, several broadband homogeneous and heterogeneous gain media are characterized, and corresponding …
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Novel Applications of Terahertz Quantum Cascade Lasers: Gas Spectroscopy, Active Control & Nearfield Imaging
Since the advent of Terahertz (THz) quantum cascade lasers (QCLs) in 2002, they have seen significant improvement in output power, operating temperature, and spectral coverage as well as having been widely applied to astronomical applications, imaging, and spectroscopy because of their high output …
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Towards room-temperature Terahertz Quantum Cascade Lasers : directions and design
Terahertz Quantum Cascade Lasers (THz QCLs) are arguably the most promising technology today for the compact, efficient generation of THz radiation. Their main limitation is that they require cryogenic cooling, which dominates their ownership cost. Therefore, achieving room-temperature operation is …
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n-type silicon-germanium based terahertz quantum cascade lasers
Terahertz quantum cascade lasers (THz QCLs) have many potential applications, including detection of skin tumours, and of illicit drugs and explosives. To date, all THz QCLs use III–V compound semiconductors, but silicon (Si)-based devices could offer significant benefits. The high thermal …
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New frontiers in THz quantum cascade lasers
Terahertz (THz) frequencies (0.5-10 THz) are among the most underdeveloped electromagnetic spectra, even though their application potentials are great in imaging, sensing, and communications. This underdevelopment is primarily due to the lack of compact and powerful THz sources. The invention of …
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Novel waveguides for terahertz quantum cascade lasers
… their first demonstration in 2002, terahertz (THz) quantum cascade lasers (QCLs) have proven to be one of the most reliable sources of this type of radiation. Advances have been made in increasing maximum operating temperature, shaping the beam and tuning the frequency and bandwidth. Waveguide …
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Laterally confined THz sources and graphene based THz optics
… in the electromagnetic spectrum, the Terahertz (THz) gap, provides an exciting opportunity for future wireless communications as this band has been under utilised. This doctoral work takes a two-pronged approach into closing the THz gap with low-dimensional materials. The first attempt addresses …
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Optically detected terahertz resonance spectroscopy of semiconductor nanostructures
… system, using quantum cascade lasers (QCLs). This system can be used for investigating various terahertz (THz) resonances in semiconductors. We use a THz QCL, of an appropriate frequency, operating in the close vicinity of the sample. Due to the small size of the QCLs, we can mount them …
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Electrically tunable terahertz quantum cascade lasers
… tunable terahertz quantum cascade lasers (THz QCLs) are designed and demonstrated. Two MEMS tuner devices are proposed to achieve electrically tunable THz QCLs. One is the electrostatic comb drive actuated tuner design and the other one is a two-stage flexure design that is actuated by an …
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Terahertz imaging and quantum cascade laser based devices
The terahertz (THz) frequency range (f=0.3-10 THz, [lambda]=30-1000 lam) is much less technologically developed that the adjacent microwave and infrared frequency ranges, but offers several advantages for imaging applications: THz wavelengths offer better spatial resolutions than microwave …