Spectral and temporal characteristics of a subpicosecond KrF excimer laser are determined with the use of a one meter spectrometer, a single shot intensity autocorrelator, and a single shot phase sensitive autocorrelator. Spectral analysis is shown to be a simple and sensitive method for aligning the laser system. Experimental results and model calculations show that the center of the laser spectrum is influenced by self phase modulation. Near the edge of the amplifier gain bandwidth, the spectrum is also influenced by the vibrational levels of the KrF upper state. To support the spectral analysis, temporal measurements are performed with single shot autocorrelators. Using a single shot autocorrelator based on three photon fluorescence of XeF, the pulse width was measure at 477 fs. To determine the frequency chirp of the laser, a single shot phase sensitive autocorrelator for ultraviolet lasers was designed, and preliminary tests were performed.