Ss the laser solves more and more problems in industry and the laboratory, applications follow for laser instrumentation that can analyze a laser's power, energy, beam quality and stability. And as the laser expands its abilities to meet the needs of new applications, so must the instrumentation that assures the laser is operating correctly.Among the recent trends in laser technology is a significant increase in pulse reletition frequencies. Ten years ago, 40 Hz was the high end for commercial energy meters. This was sufficient because at the time most Nd:YAG and excimer lasers operated at 20 Hz or less; until very recently, lasers with pulse repetition frequencies of 400 Hz were rare.However, new applications such as deep-ultraviolet microlithography and micromachining are pushing manufacturers to develop lasers that pulse at 1 kHz (Figure 1), and they will likely reach beyond that in the near future. As diode-pumped solid-state lasers and excimer lasers push repetition rates ever higher, customers will demand that instrumentation manufacturers keep up…