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In the THz spectral region quantum detectors are intrinsically limited by the small energy of the electronic transition involved in photon absorption. To overcome this problem and improve detector performances, we propose novel approaches in which concepts borrowed from high frequency electronics and metamaterials are exploited to realize THz detectors. In particular, we have investigated sub-wavelength...
In this work we demonstrate a technique for all-optical pulse-shaping in a parallel-plate waveguide (PPWG). Using a spatially-patterned 1.05 μm fs pump pulse, the dielectric function of the silicon-filled PPWG is periodically modulated, changing the dispersion of a THz pulse propagating along the modulation axis by local injection of charge carriers. The structure shows resonant transmission and reflection...
We discuss the numerical simulation of high current density InGaAs/AlAs/InP resonant tunneling diodes with a view to their optimisation as THz emitters. We introduce a figure of merit based upon the ratio of maximum extractable THz power and the electrical power developed in the chip. The aim being to develop high efficiency emitters as output power is presently limited by catastrophic failure. A...
One major hurdle for antennas created from metallic resonators is their low radiation efficiencies due to increasing Ohmic loss at terahertz frequencies. A potential solution to overcome this is to substitute metal with dielectric materials in designing resonators. Dielectric resonator antennas (DRAs) resonate based on the confinement of displacement current, at specific resonance frequencies. Hence,...
Here we report the results of terahertz photonic elements frequency analysis by the ac Josephson effect. We considered planar resonators. There were observed excitation of fundamental and dipole resonance modes in photonic elements by Josephson oscillations of YBa2Cu3O7−x bicrystal junction. Spectral characteristics of electrodynamic structures were restored with the usage of equivalent circuit. Regimes...
We demonstrate ultrastrong light-matter coupling between less than 80 electrons located in the last occupied Landau level of an high mobility 2 dimensional electron gas and a LC resonator with an extremely small effective mode volume Veff /λ3 = 4 × 10−10. The unperturbed frequency is 300 GHz and the measured normalized coupling ratio is Ω/ω = 0.35.
We present a study on a dolmen structure, where a bright resonator couples to a dark resonator, to investigate near-field signatures of electromagnetically induced transparency. We demonstrate an enhancement of the near-fields in the spectral vicinity of the transparency, and observe mode hybridization resulting from the coupling between the two resonant structures.
We have proposed a novel design for a contact grating setup with an incorporated Fabry-Perot resonator for intense terahertz (THz) light generation. This setup is scalable and extremely compact as compared with the conventional LiNbO3 prism setup. We evaluated the THz generation process in the device by experimental and calculated studies, and optimized the device to obtain maximum THz output.
We present modified circular patch resonators and discuss their potential for coupling to semiconductor heterostructures. We theoretically investigated these structures in combination with asymmetric QWs for second-harmonic generation (SHG) and parametric conversion (PC). The Q-factor of modes of the bare (empty) circular plasmonic resonator is proved to be at least 40 and a mode overlap factor of...
Terahertz (THz) magnetic field directly interacts with spin systems through Zeeman torque, enabling selective excitation of magnetic order dynamics. Here we demonstrate coherent THz-control of macroscopic magnetization in ErFeO3 using metamaterial-enhanced magnetic nearfields. We fluctuated initial process of laser-induced spin reorientation transition to modify the coherent path of phase transition,...
A THz laser source based on stimulated polariton scattering (SPS) in an intracavity RbTiOPO4 (RTP) crystal is reported, with frequency-tunable output from 3.10 to 3.16 THz and from 3.50 to 4.15 THz. The gap exhibited from 3.17 to 3.49 THz is located in the vicinity of the 104 cm−1 absorbing mode in RTP. A maximum average output power of 16.2 μW was measured at 3.80 THz.
We use photo-conductive micro-probe tips to demonstrate full vectorial mapping of the complex electric near-field in the vicinity of resonant structures at THz frequencies. We further show that characterization of these structures based on far-field spectroscopy can be indeterministic. Hence, there is a necessity to use near-field techniques for the accurate characterization of THz resonators.
We demonstrate a 0.55 THz near-field sensor implemented in 0.13 μm SiGe HBT technology from IHP Microelectronics. The sensor utilizes a differential split-ring resonator for evanescent field sensing and on-chip illumination and detection circuitry to enable future large scale sensor array implementations. It provides a dielectric permitivity dependent image contrast and a lateral resolution of 8 μm...
We propose a room temperature, all electrical driving and detecting, very sensitive bolometer using a doubly clamped microelectromechanical (MEMS) resonator, which can be excited and detected by using piezoelectric effect. The device detects the shift in the resonance frequency caused by heating and works as a very sensitive bolometer. The preliminary device showed a frequency responsivity about 100...
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