Emerging technologies in the field of thermometry

Abstract

The past decade saw the emergence of new temperature sensors that have the potential to disrupt a century-old measurement infrastructure based on resistance thermometry. In this review we present an overview of emerging technologies that are either in the earliest stages of metrological assessment or in the earliest stages of commercial development and thus merit further consideration by the measurement community. The following emerging technologies are reviewed: Johnson noise thermometry, optical refractive-index gas thermometry, Doppler line broadening thermometry, optomechanical thermometry, fiber-coupled phosphor thermometry, fiber-optic thermometry based on Rayleigh, Brillouin and Raman scattering, fiber-Bragg-grating thermometry, Bragg-waveguide-grating thermometry, ring-resonator thermometry, and photonic-crystal-cavity thermometry. For each emerging technology, we explain the working principle, highlight the best known performance, list advantages and drawbacks of the new temperature sensor and present possibilities for future developments.

Progress towards in-situ traceability and digitalization of temperature measurements

“…Further developments in the pipeline include demonstration of the feasibility of photonic-based 'lab on a chip' thermometry approaches for in-situ traceability to the kelvin. Three approaches in various stages of investigation by NPL and its collaborators to facilitate direct in-situ traceability are Doppler Broadening, Ring-Resonator, and Whispering Gallery thermometry [13].…”

Towards Realising the Redefined Kelvin

“…Such an approach will be needed to make autonomous production truly a reality. Such approaches could be through practical Johnson Noise Thermometry (where practical demonstrator devices already exist) [69,70] and in the longer-term small-scale Doppler Broadening Thermometry [71,72] as well as other photonic based approaches [73].…”

Towards Digitalization of Temperature Measurements

“…Further developments in the pipeline include demonstration of the feasibility of photonic-based 'lab on a chip' thermometry approaches for in-situ traceability to the kelvin. The approaches most likely to facilitate direct in-situ traceability are Doppler Broadening, Ring-Resonator, and Whispering Gallery thermometry [13]. Acoustic gas thermometry is also a candidate for practical primary thermometry; such a device was used to determine the Boltzmann constant with unmatched accuracy as part of the global endeavour to redefine the kelvin in terms of fundamental constants [14].…”