An odd little news item I found by following a thread from Yahoo: <http://www.redorbit.com/news/technology/1781271/ptb_terahertz_calibration_satisfies_us_laser_manufacturer>.
There's nothing unusual in calibrating a laser with metric units. Maybe the German scientist almost apologetically mentioned SI units to the interviewer, who then may have supposed that SI was the significant feature of the calibration. Traceability is a related issue.
