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Tim Bayer

Publications and source records attributed to Tim Bayer.

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Shaper-based dispersion scan for the characterization of polarization-shaped laser fields

We present a pulse-shaper-based dispersion-scan (d-scan) framework for the combined generation and characterization of polarization-tailored femtosecond laser fields. By integrating a programmable $4f$ pulse shaper with polarization-resolved d-scan measurements, the framework enables the programmable synthesis and reconstruction of complex time-dependent polarization states. We demonstrate its capabilities for several classes of vector fields, including counter-rotating circularly polarized pulse pairs, oppositely chirped counter-rotating circularly polarized pulses, polarization-gate pulses, and multi-pulse sequences utilizing polynomial, periodic and discrete spectral phase functions. The reconstructed temporal electric fields and time-dependent ellipticities show excellent agreement with the simulated target fields and accurately reproduce the defining features of each pulse class. By combining the versatility of programmable pulse shaping with the robustness of the d-scan technique, this approach provides a flexible platform for the generation and validation of polarization-tailored ultrashort laser fields in ultrafast photonics and light-matter interaction studies.

physics.optics

Multiphoton ionization with three-dimensional light fields

We report the first observation of free-electron angular momentum wave packets generated by atomic multiphoton ionization with bichromatic three-dimensional (3D) polarization-tailored ultrashort laser fields. These fields, created by the non-collinear superposition of two polarization-shaped pulses of different colors from a supercontinuum polarization pulse shaper, provide electric-field components along all spatial directions. The resulting photoelectron momentum distributions, recorded via velocity map imaging, demonstrate full 3D coherent control of electronic superposition states extending beyond the constraints of planar polarization fields by unlocking all dipole selection rules $\Delta m = 0,\pm1$. As an application, 3D pump-probe fields are used to image previously unobserved photoelectron wave packets mapping spin-orbit dynamics of the potassium $3d$ fine structure doublet. Our shaper-based approach establishes a route to fully controllable 3D light fields for chiral-sensitive light-matter interactions and ultrafast spectroscopy.

physics.atom-ph