1,721,026 research outputs found
Method and system for characterizing short and ultrashort laser pulses emitted with a high repetition rate
No full textUltrafast plasma mirrors in the microwave range
Full text linkAn experimental and numerical study of a laser-driven semiconductor mirror is detailed, which addresses two questions: whether a laser-induced semiconductor mirror is as good as a metal mirror in the microwave range and if
so, at which value of photoconductivity such a metallic behavior sets in. A novel time-frequency analysis is used to investigate the properties of the mirror, based on
measurements of average power transmitted through a microwave resonator. We demonstrate that a good macroscopic reflector can be realized through a semiconductor plasma, whose conductivity is orders of magnitude smaller than the one of a good metal. This non-trivial result is relevant for applications in which the mirror is requested to be switched on and off at a frequency of several gigahertz
Generation of microwave radiation by nonlinear interaction of a high-power, high-repetition rate, 1064 nm laser in KTiOPO_4 crystals
No full textWe report measurements of microwave (RF) generation in the centimeter band accomplished by irradiating a nonlinear KTiOPO4 crystal with a home-made, infrared laser at 1064 nm as a result of optical rectification. The laser delivers pulse trains of duration up to 1 μs. Each train consists of several high-intensity pulses at an adjustable repetition rate of approximately 4.6 GHz. The duration of the generated RF pulses is determined by that of the pulse trains. We have investigated both microwave- and second harmonic generation as a function of the laser intensity and of the orientation of the laser polarization with respect to the crystallographic axes of KT
Microwave emission by nonlinear crystals irradiated with a high-intensity, mode-locked laser
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Massive silicon or germanium detectors at cryogenic temperature
No full textSeveral massive silicon and germanium home-made detectors, working at cryogenic temperature, have been studied. They are the benchmarking schemes to check the possibility of realizing a semiconductor time projection chamber that could have various interesting applications in weak interaction problems. Reported here are the first results on investigations of charge collection efficiency and metal–semiconductor contact hardness. The leakage current, total depletion voltage and alpha or gamma spectroscopy are presented
Multi-GHz tunable-repetition-rate mode-locked Nd : GdVO4 laser
No full textWe report on a simple design for a multi-GHz tunable- repetition-rate diode-pumped picosecond laser. Using a plano-Brewster Nd:GdVO4 crystal in a V-folded cavity employing only readily available commercial components, we achieved passive mode-locking with 4.4-ps pulses tunable in the range 2.5-2.7 GHz. This laser is meant to be employed in the MIR experiment that aims at the detection of the Schwinger radiation (dynamical Casimir effect)
One-cm-thick Si detector at LHe temperature
No full textA silicon p-i-n diode of thickness 1 cm has been studied experimentally at liquid helium temperature. This preliminary study is aimed at the construction of a much bigger detector to detect low energy neutrino events
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