Researchers at NIST/JILA and PTB have developed the world’s most stable laser, with frequency variation of no more than 2 parts in 10,000 trillion. The new laser design, which uses single-crystal silicon instead of conventional optical glass, represents a significant improvement over previous designs and could have major implications for optical clocks, gravitational wave detection, and fundamental physics research.
The laser’s unprecedented stability will allow for the development of atomic clocks with unprecedented stability approaching 1 x 10-17 over 1 second. It will also have a dramatic impact on large-scale precision measurement instruments such as space-borne optical interferometers for gravitational-wave detection with baselines of many thousands of kilometers.
The new laser design addresses the problem of thermal fluctuations that alter the cavity dimensions and reduce frequency stability. By substituting single-crystal silicon for the ultralow expansion glass (ULE) or fused silica customarily employed in the cavity mirrors and spacers, the researchers have created an all-silicon interferometer that is insensitive to temperature fluctuations at 124 K. The group used extensive computer modeling to create a design that reduced the effects of environmental vibrations on the 21 cm long resonator.
The results show that the all-silicon system surpasses the performance of any other optical cavities ever reported. As a long-term stable frequency reference, a preliminary test has shown that it is equivalent to the stability of a hydrogen maser at time intervals up to 1,000 seconds. The scientists are already at work to improve those figures.
Source: https://www.nist.gov/news-events/news/2012/09/worlds-most-stable-laser
Keywords: Optical, Cavity, Silicon, Stability, Lasers
