Take a sneak peek at the new NIST.gov and let us know what you think!
(Please note: some content may not be complete on the beta site.).

View the beta site
NIST logo
Bookmark and Share

Fabry-Perot Displacement Interferometry


High-resolution Fabry-Perot interferometry is being developed and employed for demanding applications in mechanical displacement metrology.


Fabry-Perot interferometry has the highest resolution of any displacement sensor, below one picometer, and yet may be used to measure displacements of many centimeters. Equally important, it enables a natural and direct link to the SI unit of length, defined in terms of the speed of light. We are adapting this measurement technique to various challenges. One project underway is a new “calculable capacitor,” which realizes the electrical unit of capacitance, the Farad, in terms of the mechanical displacement of an electrode over 5 – 10 cm. Ultimately the displacement will be linked to an atomic time standard via a femtosecond-laser frequency comb. Another project involves various types of MEMS accelerometers, in which the motion of a micromechanical resonator is probed with high bandwidth to realize an acceleration measurement that is directly traceable to SI units. The details of the measurements drive the use of various cutting-edge technologies, including frequency combs, narrow-linewidth tunable lasers, and a variety of optical modulation techniques.

A high-finesse Fabry-Perot interferometer
A high-finesse Fabry-Perot interferometer mounted in a cryostat for operation at 3 K.

Start Date:

October 19, 2010

End Date:


Lead Organizational Unit:



John Lawall, NIST Staff
Mathieu Durand, Guest Researcher (Div 697)
Utku Kemiktarak, Guest Researcher
Michael Metcalfe, Guest Researcher


For Technical Inquiries:

John Lawall, NIST Staff
100 Bureau Drive, M/S 8423
Bldg 217/ A229
Gaithersburg, MD 20899
301-975-3226 Telephone
301-975-5485 Facsimile