TY - JOUR
AU - Nathan Brooks
AU - Alba Heras
AU - Bin Wang
AU - Iona Binnie
AU - Javier Serrano
AU - Julio San Román
AU - Luis Plaja
AU - Henry Kapteyn
AU - Carlos Hernández-García
AU - Margaret Murnane
AB - High-harmonic generation (HHG) is an extreme nonlinear optical process that can map the properties of an infrared driving laser beam onto short wavelength attosecond pulse trains. However, current techniques for generating circularly polarized high harmonics for probing magnetic materials and chiral systems have limitations: two-color collinear counter-rotating driving lasers result in a low cutoff photon energy, while single-color noncollinear counter-rotating schemes suffer from low conversion efficiency. In this work, we generate circularly polarized attosecond pulse trains by using a structured laser driver which has a rotating polarization and phase grating along the azimuthal coordinate. Our experimental and numerical results demonstrate the production of left and right circularly polarized harmonics, which naturally separate upon propagation. Our approach uses a single laser color in a collinear geometry, that can be scaled for high efficiency. Simulations show this scheme can extend into the soft X-ray region when driven by mid-infrared driving lasers, while preserving the same high phase-matching cutoff photon energy as for linearly polarized high harmonics.
BT - ACS Photonics
DA - 2025-01
DO - 10.1021/acsphotonics.4c01996
IS - 1
M3 - doi: 10.1021/acsphotonics.4c01996
N1 - doi: 10.1021/acsphotonics.4c01996
N2 - High-harmonic generation (HHG) is an extreme nonlinear optical process that can map the properties of an infrared driving laser beam onto short wavelength attosecond pulse trains. However, current techniques for generating circularly polarized high harmonics for probing magnetic materials and chiral systems have limitations: two-color collinear counter-rotating driving lasers result in a low cutoff photon energy, while single-color noncollinear counter-rotating schemes suffer from low conversion efficiency. In this work, we generate circularly polarized attosecond pulse trains by using a structured laser driver which has a rotating polarization and phase grating along the azimuthal coordinate. Our experimental and numerical results demonstrate the production of left and right circularly polarized harmonics, which naturally separate upon propagation. Our approach uses a single laser color in a collinear geometry, that can be scaled for high efficiency. Simulations show this scheme can extend into the soft X-ray region when driven by mid-infrared driving lasers, while preserving the same high phase-matching cutoff photon energy as for linearly polarized high harmonics.
PB - American Chemical Society
PY - 2025
SP - 495
EP - 504
EP - 
T2 - ACS Photonics
TI - Circularly Polarized Attosecond Pulses Enabled by an Azimuthal Phase and Polarization Grating
UR - https://doi.org/10.1021/acsphotonics.4c01996
VL - 12
ER -