DEMONSTRATION OF A TWO-PHOTON ATOMIC CLOCK WITH LIGHT SHIFT SUPPRESSION USING TWO-COLOUR MAGIC WAVELENGTHS
Abstract
There has long been a need for high quality timing in military applications – the most well-known application is connected to navigation. Global Navigation Satellite Systems (GNSS) (of which Global Positioning System (GPS) is the prime example) make use of high-quality clocks on satellites to provide positioning, navigation, and timing (PNT) to assets in the field. In response to the need for improved PNT information in the field, there is a strong motivation to develop improved GNSS clocks. In parallel, there is a drive to develop independent navigation systems that do not depend on GNSS signal reception. Adaptable Navigation Systems provide local navigation signals that are immune to GNSS vulnerabilities such as intentional jamming/spoofing. To answer both needs, small size, weight and power (SWaP) clocks are required with higher performance than existing clocks. One promising approach lies in the use of simple and compact atomic vapour clocks that use two-photon optical transitions for excitation and probing. However, atomic clocks based on two-photon transitions are well-known to suffer large light shifts that lead to unwanted long-term drifts and timing instability. A method for reducing the effect of light shifts is to judicious tuning of the powers and wavelengths of the probing laser sources into a “magic” configuration. Over the last year we have been characterising the light-shifts of our two-photon clock and we are in the process of identifying the “magic” configuration of operation. This project will implement the identified magic clock configuration that will reduce the timing sensitivity to laser power fluctuations. We believe this is the first time that this will have been demonstrated and modelled. Our approach can be readily applied to many other clock configurations and thus this pioneering work is likely to have a broad impact on the field.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 11, 2021
- Source ID
- FA23862014032
Entities
People
- Chris Perrella
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Adelaide