Absolute extreme-ultraviolet metrology

NIST has a long-standing program for the calibration of extreme ultraviolet optical components. Early activities, which began with the advent of the Synchrotron Ultraviolet Radiation Facility (SURF) almost 40 years ago, centered on the development and characterization of detectors for extreme ultraviolet (EUV) radiation. About a decade ago the program was expanded to include reflectometry of normal- incidence EUV multilayer optics. Both calibrated detectors and EUV optics are used by researchers in private industry, academia, and government, in such diverse fields as EUV lithography, astronomy, and plasma physics. Since the inception of SURF, nearly 800 transfer standard photodiodes have been issued to customers, and over 500 measurements of other EUV optical components have been made. NIST researchers, in collaboration with U.S. companies, have developed new, high-quality radiometric detectors for use throughout the EUV spectral range. We will discuss the history of NIST's involvement in EUV metrology and offer examples of our recent work.