Construction of a pump‐probe system for observing time‐resolved sum frequency images

Abstract

We combined a pump-probe technique with optical sum frequency microscopy, and demonstrated a time-resolved SF intensity image observation of an H-Si(111) surface in ultrahigh vacuum (UHV) conditions. After pump-light irradiation of photon energy 2.33 eV, pulse duration ∼30 ps, and the width of the spot ∼304 µm, SF intensity image resonant to the Si-H stretching vibration with IR probe wavenumber of 2085 cm −1 was darkened dramatically at 0 ps and then gradually recovered. Nonresonant SF signals with IR probe wavenumber of 2020 cm −1 increased at the probe delay time ∼0 ps, and then decreased with the life time of ∼1 ns. The width of the spatial profile of the nonresonant signal was at a minimum of ∼436 µm at the delay time 26 ps, and then increased to ∼673 µm at 930 ps. The origins of these behaviors of the SF intensity images are discussed.

Second-Order Nonlinear Optical Microscopy of a H–Si(111)1 × 1 Surface in Ultra-High Vacuum Conditions

“…However, no one has developed SFG microscopy for observing a sample in UHV conditions. Thus, we decided to develop a multifunctional SFG microscope to facilitate convenient analysis of a semiconductor surface under UHV conditions [28][29][30][31][32].…”