Applications of ultrafast wavefront rotation in highly nonlinear optics

Abstract

This paper provides an overview of ultrafast wavefront rotation of femtosecond laser pulses and its various applications in highly nonlinear optics, focusing on processes that lead to the generation of high-order harmonics and attosecond pulses. In this context, wavefront rotation can be exploited in different ways, to obtain new light sources for time-resolved studies, called 'attosecond lighthouses', to perform time-resolved measurements of nonlinear optical processes, using 'photonic streaking', or to track changes in the carrier-envelope relative phase of femtosecond laser pulses. The basic principles are explained qualitatively from different points of view, the experimental evidence obtained so far is summarized, and the perspectives opened by these effects are discussed.

Controlling the velocity of ultrashort light pulses in vacuum through spatio-temporal couplings

“…For instance, a simple effect known as simultaneous spatio-temporal focusing has become widely exploited in nonlinear microscopy to increase the field of view without compromising depth resolution [11][12][13]. Its close relative [13,14], ultrafast wavefront rotation [15], has enabled the generation of new ultrashort light sources called attosecond lighthouses [16][17][18]. More recently, theoretical studies have shown how a new type of linear nondiffracting beams could be produced by using ultrashort pulses where the k vector of each plane wave component is correlated to its frequency in a specific manner [19,20].…”

Generation of Attosecond Light Pulses from Gas and Solid State Media

“…In this case a single recollission in an atomic ensemble leads to the emission of a single XUV burst with continuum spectral power distribution (illustrated with black solid line in the down panel of Figure 1c) and the shortest duration of the asec pulse is limited by the XUV spectrum passing though the band pass XUV filter. Isolated pulses can be produced using (I) part of the continuum XUV radiation emitted using single-cycle driving laser fields [83]; (II) the cut-off region of the quasi-continuum XUV spectrum emitted using few-cycles driving laser fields [29]; (III) part of the continuum XUV radiation emitted using few-cycle driving laser fields in combination with PG approaches [62,63]; (IV) part of the continuum XUV radiation emitted using few-cycle driving laser fields in combination with IG approaches [63,65,66] part of the continuum XUV radiation emitted using multi-cycle driving laser fields in combination with LH approaches [67][68][69] and (V) part of the continuum XUV radiation emitted using multi-cycle driving laser fields in combination with PG approaches [49,64,[70][71][72]107]. In all cases the stability of the CEP of the laser system is a decisive matter, while if this is not possible (as in the case of high power multi-cycle laser systems), approaches for selecting single asec pulses by shot-to-shot measuring the CEP value are required [71,108].…”

“…This way, by using an appropriate spatial mask, one can obtain not only a single asec pulse but even better, a manifold of independent yet perfectly synchronized asec pulses, ideally suited to pump-probe spectroscopy. The advantage of this technique is that it is relatively simple to implement and universally applicable to any nonlinear mechanism responsible for asec pulse generation, and also offers many exciting new tools for asec metrology [69].…”

“…They recently measured the temporal structure of the individual asec beamlets generated via the lighthouse effect and found that the latter does not change their characteristics for applications [143], while proposed advanced lighthouse schemes can be found in a comprehensive review on the subject by Quéré et al in Ref. [69].…”

“…The "pulse manipulation optics" concern the optical arrangements used for the manipulation of the XUV generation process through the control of the driving field waveform. Such arrangements are used for the generation of isolated asec pulses by multi-cycle laser fields, utilizing the PG [64,[70][71][72] and LH [69] approaches. "XUV focusing" concern the optical elements/configurations (lens, focusing mirrors, deformable mirrors) used for the optimization of the XUV emission through the focusing conditions.…”