Generating few-cycle radially polarized pulses

Abstract

A radially polarized beam is axially symmetric and is able to produce tightly focused light fields beyond the Gaussian beam diffraction limit. However, with the current technology, its duration is limited by the relatively narrow bandwidth that the generation techniques can support. Using a 10 cycle pulse with a central wavelength of 1.8 μm, we show that radially polarized beams can be compressed to the few-cycle regime, while still maintaining their radially polarized nature. Therefore, it seems feasible, using only well-developed methods, to reach focused intensities of ∼10 19 W∕cm 2 . Conversion via high-harmonic generation will also open a route for applications in attosecond science, especially for a wide range of optical measurements and optical control that require high spatial and high temporal resolution. Fig. 4. Polarization measurement of the radially polarized beam. (a) Beam profile without polarization selection. (b-e) Beam profiles upon propagation through a polarizer, measured with a CCD camera for four different axis angles.

Tesla-Scale Terahertz Magnetic Impulses

“…In addition, we note several variations of this scheme that will enable further scaling of the magnetic field amplitude. Cylindrical vector beams can now be produced with pulse duration of less than 15 fs [36], thereby allowing significantly faster rise-time fields. In the other extreme, implementing this approach using kilo-Joule-scale pulses at laser facilities would provide yet higher electric fields from driving higher currents, albeit with more complex ionization and plasma dynamics.…”

Singularities in the flying electromagnetic doughnuts

“…Our findings put forward the FD pulse as an ideal platform to study the instantaneous field singularities of ultrafast vector polarized pulses in both the paraxial and strongly focused regime without resorting to approximations. We anticipate that our results will be relevant to the experimental and theoretical efforts involving the generation, propagation properties and light matter interactions [17,18,[21][22][23][24][25][26]. We note that although a part of the fine topological structure in the FD pulse occurs at spatial regions of very low energy, a number of intriguing features manifest close to regions of relatively high energy (e.g.…”

Geometric Phase in Optics: From Wavefront Manipulation to Waveguiding

“…[ 166 ] When tightly focused, these structured beams show a complex 3D dynamics of their polarization, with the optical field describing a Möbius strip while evolving in time. [ 167,168 ] Furthermore, ‐plates have been used for several applications where vector beams are required, such as mode division multiplexing, [ 169,170 ] STED microscopy, [ 171 ] nonlinear propagation of structured beams, [ 172 ] nanostructuring of surfaces via femtosecond ablation, [ 114,173,174 ] radial polarizers for ultrashort pulses [ 175 ] high‐harmonic generation with angular momentum, [ 176 ] and nodal areas in coherent beams. [ 177 ] The ‐plates discussed above are all based upon permanent structuring of the sample, being the meta‐atoms distribution or the anchoring conditions determining the direction of the liquid crystal molecules.…”