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We proposed a novel planar meta-atom structure supporting higher order Fano resonances. The unit cell consists of a plasmonic defective corrugated metallic disk (CMD). The numerical and experimental results reveal that higher order Fano resonances can be generated at terahertz frequencies when symmetric CMD is broken with small defective angle. Such higher order Fano resonances result from the coupling...
We present a novel photoconductive terahertz source that can generate high power and broadband terahertz radiation with high optical-to-terahertz conversion efficiency. The high optical-to-terahertz conversion efficiency is achieved by confining the optical pump photons very tightly around the radiating elements of the photoconductive source. A distributed Bragg reflector and plasmonic nanostructures...
We report on large-area photoconductive THz emitters and detectors with an LT-GaAs active region fabricated on quartz substrates using a lift-off transfer process. These devices are compared to the same LT-GaAs emitters when fabricated on the growth substrate. We find that the transferred devices show higher optical-to-THz conversion efficiencies and significantly larger breakdown fields.
We report on a new design of room-temperature terahertz quantum cascade lasers (THz QCLs) based on ZnMgSe/ZnSe material systems employing two-well design schemes with alternating quantum barrier heights and n-type delta-doping of the injector well. Our calculations show that this new THz QCLs achieves high optical gain at the emission frequency of 1.33 THz at room-temperature.
A WR-3 waveguide band dynamic organic lens has been designed and its performance analysed using the CST Studio Suite software. In order to determine the dynamic behaviour of the lens, the patterned distribution of the electron-hole pairs in the photo-active region of the organic lens was input to the software, as a change in the complex permittivity. The dielectric response of the organic polymer...
A number of silicon diffractive optical elements, which enabled transforming NovoFEL Gaussian beam into the Laguerre-Gaussian and Hermite-Gaussian ones, have been designed and fabricated. Other elements transformed the NovoFEL beam into determined volumes (i. e., a pencil-like beam), or areas (i. e., a uniformly illuminated square). A problem of strong Fresnel reflection was solved by the use of anti-reflection...
We have demonstrated a monolithically integrated optical phase lock loop based on a foundry fabricated photonic integrated circuit. The InP chip contains PIN photodiodes integrated with a 1.5 μm DBR laser which can be phase stabilised with respect to an external optical reference tone at all wavelengths throughout its 1 THz (8 nm) tuning range. The frequency offset between the two lasers can be set...
The knowledge of the optical properties of cryogenic detectors at operational conditions is crucial for metrological applications. An analytical model to calculate the transmittance, reflectance and absorbance for a microstructured metal mesh is proposed. The model is based on resistance measurements and geometrical dimensions. The model agrees well with numerical calculations and measurement results.
We present a method for tailoring emission field profiles through engineering of double-metal (DM) emitters. A device with a circular DM pattern is characterized and shown to emit a radial electric field profile, ideal for coupling to coaxial waveguides.
We present, evaluate and discuss the viability of commercial 3D printer filaments for use in terahertz 3D printing applications. This is achieved in a combined approach, analysing optical and mechanical properties in conjunction with the filaments' overall printability. We analyse 18 common and exotic filaments including: acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), nylon, polyethylene...
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