Special OSE Seminar by Christopher Holloway on the QUEST for Fundamentally New SI-Traceable Electric Field and Power Measurement Techniques: From Atoms to Radiation Pressure

Departmental News

Christopher Holloway

Posted: January 29, 2020

Date: Friday, January 31, 2020 

Time:  1:00 PM to 2:00 PM

Location:  PAIS, Room 2540

Map to PAIS:

Room 2540 is located on the second floor.  Go up the center steps and turn left. Go to the end of the hall and Room 2540 is located on the left. 

ADA Accommodations are available. Please contact Doris Williams at dorisw@chtm.unm.edu.


Christopher Holloway,

NIST, Boulder


One of the keys to developing new science and technologies is to have sound metrology tools and techniques. Fundamental to all electromagnetic measurements is having accurately calibrated probes, antennas, and power meters in order to measure either electric (E) fields or power. A stated goal of international metrology organizations, including the National Institute of Standards and Technology (NIST), is to make all measurements directly traceable to the International System of Units (SI). The world of measurement science is changing rapidly with the SI redefinition that occurred in November of 2018. As a result of the shift towards fundamental physical constants, the role of primary standards must change. NIST is investigating two fundamentally new direct SI traceable approaches: atom-based and mass-based (i.e., Planck’s constant and the kilogram), both of which will be traceable to Planck’s constant in the redefined SI. Traceability through Planck’s constant will exploit the quantum states of Rydberg (excited) atoms and traceability to the kilogram will make use of RF radiation pressure measurements.

The new atom-based new approach utilizes Rydberg atoms and will lead to a self-calibrated, SI traceable, E-field measurement, and has the capability to perform measurements on a fine spatial resolution in both the far- and near-fields. The atom-based approach is very broadband allowing for measurement from 10 MHz to 1 THz with one probe head. This approach can measure field levels from 1 micro-V/m (and possibly lower) to 100’s kV/m (and possibly higher). The atom-based approach has led to a fundamental new method for traceable RF power measurements. This new power measurement method can lead to the development of an in-situ calibrated sources as well. Finally, the atom-based approach has also led to many other applications: atom-based receivers/antennas, atom-based recording device of musical instruments, RF cameras, and many more applications.

The mass-base (through radiation-pressure) approach will allow power to be traceable of the kilogram and will allow for in situ measurements. This radiation-pressure technique could potentially allow electromagnetic power measurements and calibrations from 1mW to 1MW (and higher) regardless of frequency (from UV to RF) with one traceability chain. Significant progress has recently been made in the development of these novel approaches over the past few years and in this talk I will summary the work to date.