Univ. of Pittsburgh, PA (United States). Dept. of Physics and Astronomy and Pittsburgh Quantum Institute; I. Georg-August-Universität Göttingen (Germany). Physikalisches Institut; Condensed Phase and Interfacial Molecular Science (CPIMS)
Univ. of Pittsburgh, PA (United States). Dept. of Physics and Astronomy and Pittsburgh Quantum Institute
Exciting solids with intense femtosecond laser pulses prompts electrons of the interrogated material to respond in a highly nonlinear manner, as is evident in the emission of high-order harmonic radiation and photoelectrons with kinetic energies well above that of the driving photons. Such high-field interactions can be resolved, for example, in above-threshold multiphoton photoemission (ATP) spectroscopy. In this work, we interrogate the nonlinear photoelectric responses of the pristine copper, silver, and gold noble metal surfaces in (111) and (100) crystal orientations in the perturbative regime. Using multiphoton photoemission spectroscopy (mPP) excited by finely tuned optical fields, we characterize enhancement of the mPP and ATP yields from (111) surfaces in selected k||-momentum ranges when the occupied Shockley surface (SS) states are (near-)resonantly coupled by multiphoton transitions to image potential (IP) intermediate states in the excitation process. The ATP signal from the IP states of (111) surfaces is largely defined by their formation through polarization of SS electrons; this observation is contrasted with ATP experiments from the Ag(100) surface, for which the SS becomes an unoccupied resonance and the IP states can only be excited from bands with significantly more bulk character. In addition, based on the optical power and nonlinear order-dependent mPP spectra, we provide evidence for ATP being a one-step, rather than a sequential process, as previously postulated.
@article{osti_1598264,
author = {Reutzel, Marcel and Li, Andi and Petek, Hrvoje},
title = {Above-threshold multiphoton photoemission from noble metal surfaces},
annote = {Exciting solids with intense femtosecond laser pulses prompts electrons of the interrogated material to respond in a highly nonlinear manner, as is evident in the emission of high-order harmonic radiation and photoelectrons with kinetic energies well above that of the driving photons. Such high-field interactions can be resolved, for example, in above-threshold multiphoton photoemission (ATP) spectroscopy. In this work, we interrogate the nonlinear photoelectric responses of the pristine copper, silver, and gold noble metal surfaces in (111) and (100) crystal orientations in the perturbative regime. Using multiphoton photoemission spectroscopy (mPP) excited by finely tuned optical fields, we characterize enhancement of the mPP and ATP yields from (111) surfaces in selected k||-momentum ranges when the occupied Shockley surface (SS) states are (near-)resonantly coupled by multiphoton transitions to image potential (IP) intermediate states in the excitation process. The ATP signal from the IP states of (111) surfaces is largely defined by their formation through polarization of SS electrons; this observation is contrasted with ATP experiments from the Ag(100) surface, for which the SS becomes an unoccupied resonance and the IP states can only be excited from bands with significantly more bulk character. In addition, based on the optical power and nonlinear order-dependent mPP spectra, we provide evidence for ATP being a one-step, rather than a sequential process, as previously postulated.},
doi = {10.1103/PhysRevB.101.075409},
url = {https://www.osti.gov/biblio/1598264},
journal = {Physical Review B},
issn = {ISSN PRBMDO},
number = {7},
volume = {101},
place = {United States},
publisher = {American Physical Society (APS)},
year = {2020},
month = {02}}
Univ. of Pittsburgh, PA (United States). Condensed Phase and Interfacial Molecular Science (CPIMS)
Sponsoring Organization:
Alexander von Humboldt Foundation; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division
12th European Quantum Electronics Conference CLEO EUROPE/EQEC, 2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE/EQEC)https://doi.org/10.1109/cleoe.2011.5943576
2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), 2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEOPR)https://doi.org/10.1109/cleopr.2013.6600311
ICALEO® 2007: 26th International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing, International Congress on Applications of Lasers & Electro-Opticshttps://doi.org/10.2351/1.5061046