Quantum efficiency of photoemission from biased metal surfaces with laser wavelengths from UV to NIR

This paper studies photoelectron emission from metal surfaces with laser wavelengths from 200 to 1200 nm (i.e., ultraviolet to near-infrared), using a recent quantum model based on the exact solution of time-dependent Schrodinger equation. The dominant electron emission mechanism varies from different multiphoton emission processes to dc or optical field emission, depending on the laser intensity, wavelength, and dc bias field. The parametric dependence of the quantum efficiency (QE) is analyzed in detail. It is found that QE can be increased nonlinearly by the non-equilibrium electron heating produced by intense sub-picosecond laser pulses. This increase of QE due to laser heating is the strongest near laser wavelengths where the cathode work function is an integer multiple of the corresponding laser photon energy. The quantum model, with laser heating effects included, reproduces previous experimental results, which further validates our quantum model and the importance of laser heating.

Automated summary

This study investigates photoelectron emission from metal surfaces with laser wavelengths ranging from 200 to 1200 nm using a quantum model. It shows that non-equilibrium electron heating from intense sub-picosecond laser pulses can nonlinearly increase quantum efficiency, which is strongest when the cathode work function is a multiple of the laser photon energy. By reproducing previous experimental results, the quantum model with laser heating effects validates the importance of laser heating in electron emission mechanisms.