The paper describes a time- and angle-resolved photoemission apparatus consisting of a hemispherical analyzer and a pulsed laser source. We demonstrate 1.48-eV pump and 5.90-eV probe measurements at the >10.5-meV and >240-fs resolutions by use of fairly monochromatic 170-fs pulses delivered from a regeneratively amplified Ti:sapphire laser system operating typically at 250 kHz. The apparatus is capable to resolve the optically filled superconducting peak in the unoccupied states of a cuprate superconductor, Bi2Sr2CaCu2O8+d. A dataset recorded on Bi(111) surface is also presented. Technical descriptions include the followings: A simple procedure to fine-tune the spatio-temporal overlap of the pump-and-probe beams and their diameters; achieving a long-term stability of the system that enables a normalization-free dataset acquisition; changing the repetition rate by utilizing acoustic optical modulator and frequency-division circuit.
@article{arxiv.1612.04910,
title = {Time-resolved photoemission apparatus achieving sub-20-meV energy resolution and high stability},
author = {Y. Ishida and T. Togashi and K. Yamamoto and M. Tanaka and T. Kiss and T. Otsu and Y. Kobayashi and S. Shin},
journal= {arXiv preprint arXiv:1612.04910},
year = {2016}
}