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The ferroelectric cathode is a cold cathode based on surface plasma, that is not widely known to the gyrotron community. It was assembled and operated is several setups of gyrotrons. Radiation was obtained in the Ka band and the W band. Power in the range of 1–30 kW with interaction efficiency of 10–15% were measured. Experiential results and the potential exploitation of the cathode will be presented.
Manufacturing tolerances at the emitter ring region of a high power gyrotron cathode structure can have a dramatic effect on the electron beam quality, and, finally, are determining the gyrotron performance which will be achieved. A sensitivity analysis of manufacturing imperfections of the emitter ring in the gyrotron cathode structure on the electron beam quality has been performed. It has been...
A high power 300 GHz band pulse gyrotron has been developed based on the design concept for stable and single mode oscillation verified with a prototype gyrotron. The oscillation frequency is 303.3 GHz and the power target is 300 kW. Oscillation test has been carried out and a maximum single mode oscillation power higher than 320 kW was attained. No competing mode was observed during the turn on and...
We demonstrate electron tunneling-induced colossal nonlinear response of vertically oriented angstrom-metallic gaps by irradiation with intense terahertz pulses. We also investigate the sub-picosecond time evolution of the induced tunneling current extracted from the transmission measurement of light passing through the metallic gap. Our technology of angstrom gap lithography enlarges the boundary...
Commercially available neon indicator lamps (also known as Glow Discharge Detectors) are low-cost, sensitive detectors operating at room temperature for mm-wave/Terahertz detection. Furthermore, their high speed operation make them attractive from the stand-point of applications in the far-infrared region of the spectrum, however questions still remain regarding the mechanisms involved in the detection...
Heterostructure low barrier diode (HLBD) based on AlGaInAs has been designed, fabricated and characterized for zero-bias millimetre-wave detection. Detectors with different heterostructures and various active areas have been tested in order to optimize their characteristics for low-level radiometric detection. We have measured the microwave performances of HLBD from DC to 220 GHz. A responsivity of...
We will report our latest achievements with ultrathin NbN films for the development of conventional antenna coupled hot-electron-bolometer (AC-HEB) and of active metadevices, i.e. a frequency selective metamaterial with an integrated bolometer.
This paper presents a terahertz (THz) spectrometer based on high temperature superconducting Josephson junction. The YBa2Cu3O7 (YBCO) bi-crystal Josephson junctions (JJS) with log-periodic antennas are used as detectors. In the low temperature, with the signal measurement, data acquisition and human-computer interactive system, the automatic measurement system of THz spectrometer is finally accomplished...
Continuous-wave (CW) terahertz (THz) photomixers are fabricated using 1-D nanocontacts on low-temperature-grown (LTG) GaAs and InGaAs, for operation wavelengths of 850 nm and 1550 nm, respectively. Silver (Ag) nanowire (NW) used as the nanocontact is aligned between the antennas patterned onto these photoconductive material by dielectrophoresis (DEP) technique. Reliable photocurrent measurements for...
Field emitters are attractive for use in diagnostic gyrotrons destined for the DNP/NMR spectroscopy. They should provide durable work of the gyrotrons at currents more than 20–30 mA. The paper demonstrates prospects of the use of the developed by the authors multi-tip silicon emitters with metal — fullerene coatings for this application.
A distributed-feedback (DFB) dual-gate graphene-channel field-effect transistor was fabricated as a current-injection terahertz laser. A single mode emission at 5.2 THz was observed at 100K beyond the threshold carrier injection level. Spectral narrowing with increasing the carrier injection around the threshold was also observed. The result is still preliminary level but the linewidth fairly agrees...
This paper presents we presents a development of the structure of the pinned photodiode terahertz rectifier, in which the metal whisker of the antenna is separated from the semiconductor by a silane oxide layer, in order to reduce the surface defectiveness. The rectifies is the basic component of an image detection system based on the structure of actual CMOS image detectors. The structure combines...
This paper reports on direct detection of electromagnetic radiation at 300GHz by using low cost commercially available GaAs high electron mobility field effect transistors (FETs) without any specially attached antennas. The effect of gate voltage bias on the photovoltaic response of the transistor was investigated. Measurements show that conventional RF FETs can be used as broadband THz detectors...
DNA semiconductor terahertz detection is considered to be the most promising approach for future genome and proteome research which is dependent on the challenges faced by semiconductor nanotechnologies.
A focal plane array of 24×24 elements for imaging applications in the 0.6–1.2 THz range was fabricated in a SOI-CMOS process and post-processed with MEMS technology. The pixels are fully released antenna-coupled CMOS microbolometers, where the sensing element is a lateral diode. The chip includes a column-multiplexed readout circuit with digital calibration and analog output. The pixel responsivity...
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