Abstract
Novel potentials of photoemission electron spectroscopy have been recently enabled to be explored by an advent of upgraded relevant technology. The enhanced signal-to-noise ratio by an advancement of measurement technology has revived attention to the extrinsic loss beyond the sudden approximation of photoemission spectroscopy. The ultrashort laser pulses and their control by the state-of-the-art laser technology have given birth to the time-resolved photoemission spectroscopy. In this issue, we introduce some studies of the extrinsic loss and the time-resolved mode of the photoemission spectroscopy.
