Polarization-sensitive strong field emission from carbon nanotubes.

Strong field photoemission from nanostructures provides a platform for studying ultrafast electron dynamics in the highly nonlinear emission regime. Here, we present a polarization-controlled photoemission approach using two orthogonally polarized fields to investigate the nonlinear emission from carbon nanotubes (CNTs). Scanning the relative phase enables a single measurement to capture the emission dependence on polarization and field strength. Based on the experimentally obtained energy spectrum data, we established a quantum model with spatially inhomogeneous fields, which reveals the reduction in electron re-collision probability and more temporally confined emission. The pronounced polarization sensitivity observed in experiments suggests that CNTs could serve as a polarization-gated platform for isolated attosecond electron pulse generation, a possibility we explore through TDSE simulations.