Determination of carrier-envelope phase of relativistic few-cycle laser pulses by Thomson backscattering spectroscopy

Abstract

A method is proposed to determine the carrier-envelope phase (CEP) of a relativistic few-cycle laser pulse via the frequency of the Thomson backscattering (TBS) light. We theoretically investigate the generation of a flying mirror when a few-cycle drive pulse with relativistic intensity interacts with a target combined with a thin and a thick foil. The frequency of the TBS light generated from the flying mirror shows a sensitive dependence on the CEP of the drive pulse. The obtained results are verified by one-dimensional particle-in-cell simulations and are explained by an analytical model.

Determining the duration of an ultra-intense laser pulse directly in its focus

“…The desire for direct laser characterization techniques, benchmarking the well-established indirect methods was consequently expressed in community meetings 33 as well as by experts on experimental high-power laser science 34 . One possible solution is quantifying the emission patterns of electrons scattered from the laser focus, giving access to a direct determination of its carrier-envelope phase 35,36 and intensity 18 , with the latter already implemented experimentally 37 . This latter experiment is in line with a series of recent experiments on laser-electron accelerators 38–40 and all-optical radiation sources 4,5,41–43 , for which there exists an abundance of refined detectors for both the electrons and emitted radiation 44 .…”

In situ characterization of ultraintense laser pulses

“…Several mechanisms have been proposed to directly extract information about high-intensity laser pulses (e.g. of the range ∼ 10 21 −10 22 Wcm −2 ), such as peak intensity [10], carrier envelope phase [11,12], and duration [13] based on the radiation emitted by electrons subjected to such fields. The advantage of this type of metrology is that the pulse properties are measured under the same conditions as present in the subsequent experiments.…”

Energy spread inhibition of compact electron bunch driven by circularly polarized laser pulse

“…This may lead to different energy of the electron bunch while a thick reflect foil setting behind with a specific distance. 20 To illustrate clearly the effect of polarization state on the energy dispersion, an energy dispersion in analytical model is defined by half of the difference between the maximal and minimal electron's energy in the electron bunch at time t: Dc M ¼ 0:5ðc max À c min Þ. 27 In Fig.…”

“…18 The energy spread may be further reduced with a nano meshed-graphene 19 as the target. 20 The energetic electrons may be used to generate brilliant x-ray by the coherent Thomsen backscattering 21,22 or even the free electron laser, 23 which states the highest requirement on the energy spread of the electron bunch. By now, the control of energy spread of the electron bunch from laser foil interaction has not been fully addressed.…”