Pulse timing leading edge

The broad peak, attributed again to ground state neutrals, could not be simply described by a simple Maxwell-Boltzmann distribution of particles emitted during the laser pulse. The leading edge of the particle distribution was far too fast to be consistent with any Maxwell-Boltzmann distribution that could account for the very long tail in the detected emissions. Thus emission appears to continue for some time after the laser pulse. Although... 

Extrapolation of the picosecond simulations would imply that isothermal and laser-induced desorption results should be in qualitative agreement for nonspecific heating pulses of 1 to 10 ns duration. Of course this may not hold if all desorption occurs during the leading edge of the laser pulse or if the desorption process is driven by a nonthermal maihanism. Nevertheless, incomplete equilibration is not expected to play a major role for translational or rotational accommodations if the residence times are longer than 10 ns. 

This time dependent phase shift leads to a frequency modulation that is proportional to the time derivative of the self induced phase shift fused silica with its positive Kerr coefficient rio = 2.5 x 10 16 cm2/W [28] the leading edges of the pulses are creating extra frequencies shifted to the red ( jvi(t) < 0) while the trailing edges causes blue shifted frequencies to emerge. Self-phase modulation modifies the envelope function according to... 

Thus from the initial intensity and the leading edge of the microwave-induced phosphorescence signal resulting from the microwave pulse given at a delay time t after cutting off the excitation, the ratio K /K can be determined. 

Varying pulse rise time by simply changing the pulse duration is not straightfoward because the laser pulses may differ in other respects. The principle of the interferometric method is to split each laser pulse into two pulses of unequal intensity, delay the main pulse and recombine them such that the low-intensity prepulse can interfere constructively or destructively with the leading edge of the main pulse, producing an increase or decrease in rise time. 

In the leading edge of the pulse (positive derivative of the intensity), the new frequencies are lower than coq they are higher in the trailing edge. This spectral broadening provides a polychromatic light source of short duration, called continuum, which is commonly used in pump-probe experiments on the femto-picosecond time scale. 

The leading-edge timing method determines the time of arrival of a pulse with the help of a discriminator, as shown in Fig. 10.20. A discriminator threshold is set and the time of arrival of the pulse is determined from the point where the pulse crosses the discriminator threshold. ... 

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