Spatio-temporal characterization of ultrashort vector pulses

Abstract

Ultrafast vectorially polarized pulses have found many applications in information and energy transfer owing mainly to the presence of strong longitudinal components and their space-polarization non-separability. Due to their broad spectra, such pulses often exhibit space–time couplings, which significantly affect the pulse propagation dynamics. Although such couplings usually result in reduced energy density at the focal spot, they have been utilized to demonstrate pulse shaping as in the case of a rotating or sliding wavefront as the pulse travels through its focal point. Here, we present a new method for the spatiotemporal characterization of ultrashort cylindrical vector pulses based on a combination of spatially resolved Fourier transform spectroscopy and Mach–Zehnder interferometry. The method provides access to spatially resolved spectral amplitudes and phases of all polarization components of the pulse. We demonstrate the capabilities of the method by completely characterizing a 10 fs radially polarized pulse from a Ti:sapphire laser centered at 800 nm.

Roadmap on spatiotemporal light fields

“…Very recently some techniques have successfully faced the challenge of measuring ultrafast vector beams [112,145,146]-i.e. ultrashort pulses with space and time dependent polarization-using different strategies, in all cases operating in the near IR region.…”

“…Recent developments on techniques for the full 3D retrieval of the electromagnetic fields of few-cycle vector polarized pulses (e.g. [112,113] and related techniques shown in chapter 13 and chapter 14 of this roadmap) can be expanded and applied to the more complex supertoroidal and ST superoscillatory pulses.…”

“…Their characterization has recently been accomplished by using two-fold spectral interferometry [145], which is based on the combination of spatially resolved spectral interferometry from a fiber coupler interferometer and inline polarization interferometry (figure 25). More recently, a combination of Fourier transform spectroscopy with a Mach-Zehnder interferometer using a linearly polarized reference pulse [112] and two-dimensional temporal scanning interferometry with a plane wave reference pulse [146] have been used for the same purpose. Since these techniques are very recent, improvements and new techniques are expected to be introduced in the near future to overcome the different challenges in the measurement of ultrafast vector beams.…”

Nonseparable States of Light: From Quantum to Classical

“…Such pulses have been shown to efficiently couple to toroidal multipoles and to non-radiating charge-current configurations (anapoles). [135,140,141] Recently, more new kinds of spatiotemporal vector pulses were designed, [142][143][144][145] and the method for experimental characterization of ultrashort vector pulses was proposed, [146,147] which can be used for fully measuring the distribution of the three DoFs, that is, space, time, and polarization. Thus we can expect that the full control of tripartite nonseparable spatiotemporal pulse is just around the corner.…”

Observation of toroidal pulses of light

“…The spatiotemporal and spatiospectral structure of the generated TLPs were characterized by hyperspectral imaging of their transverse profiles (as constructed from multiple images at different wavelengths) and by spatially resolved Fourier transform interferometry [28][29], allowing the retrieval of spectral amplitude and phase for all polarization components of the electric field at any point of the TLP.…”