Pulse-shortening and pulse broadening effects in passively mode-locked lasers are analysed. A steady-state pulse duration limit is calculated and compared with round-trip simulations. The numerical calculations apply to a picosecond N d : glass laser. Methods of short-pulse generation are discussed. PACS: 42.55R, 42.60D, 42.65 In passively mode-locked pulsed lasers the statistical spontaneous e...

This paper derives Cramer-Rao bounds on estimates of the Doppler-shifted frequency of a coherent pulse-train intercepted at a single moving antenna. Such estimates are used to locate the emitter that transmitted the pulse train. Coherency from pulse to pulse allows much better frequency accuracy and is considered to be necessary to support accurate emitter location. Although algorithms for esti...

One of the emerging trends in new accelerator techniques is the laser based acceleration of particles, known as laser – plasma acceleration. Interaction of intense ultra short laser pulse with matter generates oscillations in hot plasma and the subsequent acceleration of electrons in a wakefield .Electrons can be accelerated to around 100 MeV within 1 mm distance. Ion beams can also be produced...

A novel method of extracting heart rate and oxygen saturation from a video-based biosignal is described. The method comprises a novel modular continuous wavelet transform approach which includes: performing the transform, undertaking running wavelet archetyping to enhance the pulse information, extraction of the pulse ridge time-frequency information [and thus a heart rate (HRvid) signal], crea...

Objective. This study is performed to obtain objective diagnostic indicators associated with menstrual pain using pulse wave analysis. Methods. Using a pulse diagnostic device, we measured the pulse waves of 541 women aged between 19 and 30 years, placed in either an experimental group with menstrual pain (n = 329) or a control group with little or no menstrual pain (n = 212). Measurements were...

This paper discusses a method of designing a matched filter for a passive microwave sensor. This sensor receives pulse signals transmitted by a target active radar. Received signals can be categorized into two types due to either the pulse signals or noise. The method first estimates an autocorrelation function of the received signals. The autocorrelation of the pulse signals is then extracted ...

Nanosecond-pulse power has the characteristics of quickly increasing applied power, short pulse width, and considerably high-energy electrons. In this study, we investigated different air/helium mixture ratios nanosecond-pulsed-power-driven plasma jet discharge physicochemical properties gaseous aqueous phases. Results showed that length luminescence intensity increased with decreasing air rati...

In active sonar the target echo level is often estimated with a propagation model that adds all multipath arrivals. If the (post-correlator) transmitted pulse is short compared to the multipath time spread then there is effectively an extra loss (which may be substantial) since only a few of the paths contribute to the target echo at any one instant. This well known "time-smearing" loss is trea...

Channel characteristics of an indoor wireless optical communication system is provided here. A channel impulse response includes the power ratio and time delay due to bounce times. Based on the scenario of the indoor structure, we obtained and discussed the received power distribution according to six configurations in Table 1, which vary with respect to transmitter and receiver positions and r...

We present analytical and computational models used to investigate the dependence of etch resolution on pulse duration, tool radius, and etched feature aspect ratio in electrochemical machining with ultrashort voltage pulses. Our results predict that, for the high aspect ratio system in which the effect of trench top and bottom edges can be ignored, the increase of etch resolution with pulse le...