Topic
Pulse duration
About: Pulse duration is a research topic. Over the lifetime, 19429 publications have been published within this topic receiving 286507 citations.
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TL;DR: In this paper, the propagation and distortion of a 100 fs long pulse in a silica lens was described using wave optical theory and a fifty-fold increase of the pulse duration was calculated.
96 citations
TL;DR: In this article, a CMOS ultra wideband (UWB) pulse generator with low energy dissipation and high peak amplitude is presented for 6-10 GHz applications, which consists of a glitch generator, a pulsed oscillator, and a pulse shaping filter.
Abstract: A CMOS ultra wideband (UWB) pulse generator with low energy dissipation and high peak amplitude is presented for 6-10 GHz applications. The pulse generator complies with the FCC spectral mask for indoor UWB systems. It consists of a glitch generator, a pulsed oscillator, and a pulse shaping filter. The pulsed oscillator is switched on by the glitch signal only for a short duration, so as to make a UWB pulse. For sub-nanosecond pulse generation, a pulsed oscillator with fast transient response is proposed. A pulse shaping filter makes the oscillator output fall into the FCC spectral mask. The pulse generator is fabricated using a 0.18 mum CMOS process. The core chip has a size of 0.11 mm2. It shows pulse duration of about 500 ps with -10 dB bandwidth of 4.5 GHz from 5.9 to 10.4 GHz. The energy consumption is 27.6 pJ per pulse with a peak-to-peak amplitude of 673 mV on a 50 Omega output load. The generated pulses are very coherent with 1.8 ps RMS jitter.
96 citations
Patent•
15 Dec 2014TL;DR: In this article, a method for slope control of ion energy is described, which includes determining power levels and timings for achieving the pulse slope and sending the power levels to an RF generator to generate the RF pulse signal.
Abstract: A method for slope control of ion energy is described. The method includes receiving a setting indicating that an etch operation is to be performed using a radio frequency (RF) pulse signal. The RF pulse signal includes a first state and a second state. The first state has a higher power level than the second state. The method further includes receiving a pulse slope associated with the RF pulse signal. The pulse slope provides a transition between the first state and the second state. Also, the pulse slope is other than substantially infinite for reducing an amount of ion energy during the etch operation. The method includes determining power levels and timings for achieving the pulse slope and sending the power levels and the timings to an RF generator to generate the RF pulse signal.
96 citations
TL;DR: In this paper, a Thomson backscatter was used for the measurement of the electron temperature and density in a magnetically confined fusion plasma, which was realized for the first time on the JET tokamak.
Abstract: By combining the time‐of‐flight or LIDAR principle with a Thomson backscatter diagnostic, spatial profiles of the electron temperature and density are measured in a magnetically confined fusion plasma. This technique was realized for the first time on the JET tokamak. A ruby laser (3‐J pulse energy, 300‐ps pulse duration, 0.5‐Hz repetition rate) together with a 700‐MHz bandwidth detection and registration system yields a spatial resolution of about 12 cm. A spectrometer with six channels in the wavelength range 400–800 nm gives a dynamic range of the temperature measurements of 0.3–20 keV. The stray light problem in the backscatter geometry is overcome by spectral discrimination and gating of the photomultipliers. A ruby filter in the spectral channel containing the laser wavelength allows calibration of the vignetting along the line of sight by means of Raman scattering, enabling the measurement of density profiles. The low level of background signal due to the short integration time for a single spatial...
96 citations
TL;DR: In this article, the role of the pulse duration and laser fluence on the dynamics of the phase change and the degree of amorphization was discussed, and several advantageous features of femtosecond compared to nanosecond laser-induced amorphisation were identified.
Abstract: Phase transformations of crystalline Ge2Sb2Te5 films upon pulsed laser irradiation have been studied using in situ reflectivity measurements with temporal resolution. Two different configurations allowed point probing with nanosecond temporal resolution and imaging with subpicosecond temporal and micrometer spatial resolution. The role of the pulse duration and laser fluence on the dynamics of the phase change and the degree of amorphization is discussed. Several advantageous features of femtosecond compared to nanosecond laser-induced amorphization are identified. Moreover, a high-resolution study of the amorphization dynamics reveals the onset of amorphization at moderate fluences to occur within ∼100 ps after arrival of the laser pulse. At high fluences, amorphization occurs after ∼430 ps and the molten phase is characterized by an anomalously low reflectivity value, indicative of a state of extreme supercooling.
96 citations