Exact Theory for Two-Color Laser-Induced Photoemission from a Biased Metal Surface

Laser-induced electron emission is important to ultrafast electron microscopes, tabletop particle accelerators and x-ray sources, and novel quantum nanocircuits [1-3]. Two-color laser-induced photoemission provides great flexibility for the coherent control of ultrafast electron dynamics due to the interference effect [4]. By solving the time-dependent Schrödinger equation exactly [5-7], we found that under a large DC bias, strong modulation persists in the emission current, whose magnitude is also significantly increased. Application of our model to time-resolved photoelectron spectroscopy demonstrates the dynamics of the multi-photon excited states depends strongly on the applied DC field. Our study suggests a practical way to maintain a strong modulation to high current photoemission. [1] P. Zhang, et al., Appl. Phys. Rev. 4, 011304(2017). [2] E. Forati, et al., Nat. Communications 7, 13399 (2016). [3] P. Zhang, and Y. Y. Lau, J. Plasma Phys. 82, 595820505 (2016).[4] M. Forster, et al., Phys. Rev. Lett. 117, 217601 (2016).[5] P. Zhang and Y. Y. Lau, Sci. Rep. 6, 19894 (2016).[6] Y. Luo, and P. Zhang, Phys. Rev. B, 98, 165442 (2018).[7] Y. Luo, and P. Zhang, Phys. Rev. Applied 12, 044056 (2019).