Precision Measurement

Physicists at JILA, the joint institute of NIST and the University of Colorado, have created a new optical process to extend the production of coherent radiation into the extreme ultraviolet region of the electromagnetic spectrum. This process takes advantage of the fact that ultrafast laser pulses of femtosecond widths, separated by nanoseconds, manifest themselves as a superposition of light at different frequencies over a wide spectral band. 

We've come a long way from the days when the length of the king's forearm was used to determine an object's size. Then, it was called the cubit, but the succession of short- and long-limbed kings made uniformity difficult. More modern standardized measures have helped. But these days, even those aren't enough. That's why the agency that sets measurement standards for the United States - the National Institute of Standards and Technology - is asking American technologists to assess the needs for new ones. With 80 percent of world trade dependent on such standards, NIST wants to be up to speed.

The world's most accurate "ruler" made with extreme ultraviolet light has been built and demonstrated with ultrafast laser pulses by scientists at JILA, a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder.