Optical method for measuring thermal accommodation coefficients using a whispering-gallery microresonator

Ganta, D.; Dale, Elijah; Rezac, Jeromy P.; Rosenberger, A. T.

doi:10.1063/1.3631342

Cited by 36 publications

(38 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The relationship between the gas temperatures and the surface temperature of the sphere is given by a material constant, the accommodation coefficient α = T em −T imp Tsur−T imp . The accommodation coefficient for silica is known 19 and close to 0.777 for moderate surface temperatures around 300 K. This allows us to infer the surface temperature of the nanospheres, Tsur = 294 K + T em −294 K 0.777…”

mentioning

confidence: 90%

Nanoscale temperature measurements using non-equilibrium Brownian dynamics of a levitated nanosphere

et al. 2014

View full text Add to dashboard Cite

Einstein realized that the fluctuations of a Brownian particle can be used to ascertain the properties of its environment. A large number of experiments have since exploited the Brownian motion of colloidal particles for studies of dissipative processes, providing insight into soft matter physics and leading to applications from energy harvesting to medical imaging. Here, we use heated optically levitated nanospheres to investigate the non-equilibrium properties of the gas surrounding them. Analysing the sphere's Brownian motion allows us to determine the temperature of the centre-of-mass motion of the sphere, its surface temperature and the heated gas temperature in two spatial dimensions. We observe asymmetric heating of the sphere and gas, with temperatures reaching the melting point of the material. This method offers opportunities for accurate temperature measurements with spatial resolution on the nanoscale, and provides a means for testing non-equilibrium thermodynamics.

show abstract

mentioning

confidence: 90%

Nanoscale temperature measurements using non-equilibrium Brownian dynamics of a levitated nanosphere

et al. 2014

View full text Add to dashboard Cite

show abstract

“…In particular, a gas possesses a characteristic thermal conductivity, which can give rise to differing thermal responses. For example, the equilibrium temperature in a thermometry type setup [270] or the thermal relaxation time can be monitored [271], which are both critically dependent on the thermal conductivity of the surrounding gas. Similarly turn-on transients can also be used to discriminate different gases through their thermal conductivity [272].…”

Section: Sensingmentioning

confidence: 99%

Whispering gallery mode sensors

2015

View full text Add to dashboard Cite

We present a comprehensive overview of sensor technology exploiting optical whispering gallery mode (WGM) resonances. After a short introduction we begin by detailing the fundamental principles and theory of WGMs in optical microcavities and the transduction mechanisms frequently employed for sensing purposes. Key recent theoretical contributions to the modeling and analysis of WGM systems are highlighted. Subsequently we review the state of the art of WGM sensors by outlining efforts made to date to improve current detection limits. Proposals in this vein are numerous and range, for example, from plasmonic enhancements and active cavities to hybrid optomechanical sensors, which are already working in the shot noise limited regime. In parallel to furthering WGM sensitivity, efforts to improve the time resolution are beginning to emerge. We therefore summarize the techniques being pursued in this vein. Ultimately WGM sensors aim for real-world applications, such as measurements of force and temperature, or alternatively gas and biosensing. Each such application is thus reviewed in turn, and important achievements are discussed. Finally, we adopt a more forward-looking perspective and discuss the outlook of WGM sensors within both a physical and biological context and consider how they may yet push the detection envelope further.

show abstract

“…where p is the pressure of gas, k B the Boltzmann constant, a is the thermal accommodation coefficient which accounts for the interaction between the gas molecule and the two surfaces at temperatures T 1 = 300 K and T 2 = 0 K, M is the mass of a gas molecule (≈ 4.8 × 10 − 26 kg for air), and the functions 1 T ′ and 2 T ′ are given by The value of a can be determined experimentally and for most surfaces lies in the range 0.75-0.9 [22,23]. Here, we assume a value a = 0.8 for our calculations.…”

Section: Heat Transfermentioning

confidence: 99%

Van der Waals Force Assisted Heat Transfer

Sasihithlu

Pendry

Craster

2017

Zeitschrift Für Naturforschung A

View full text Add to dashboard Cite

Phonons (collective atomic vibrations in solids) are more effective in transporting heat than photons. This is the reason why the conduction mode of heat transport in nonmetals (mediated by phonons) is dominant compared to the radiation mode of heat transport (mediated by photons). However, since phonons are unable to traverse a vacuum gap (unlike photons), it is commonly believed that two bodies separated by a gap cannot exchange heat via phonons. Recently, a mechanism was proposed [J. B. Pendry, K. Sasihithlu, and R. V. Craster, Phys. Rev. B 94, 075414 (2016)] by which phonons can transport heat across a vacuum gap -through the Van der Waals interaction between two bodies with gap less than the wavelength of light. Such heat transfer mechanisms are highly relevant for heating (and cooling) of nanostructures; the heating of the flying heads in magnetic storage disks is a case in point. Here, the theoretical derivation for modelling phonon transmission is revisited and extended to the case of two bodies made of different materials separated by a vacuum gap. Magnitudes of phonon transmission, and hence the heat transfer, for commonly used materials in the micro-and nano-electromechanical industry are calculated and compared with the calculation of conduction heat transfer through air for small gaps as well as the heat transfer calculation due to photon exchange.

show abstract

Optical method for measuring thermal accommodation coefficients using a whispering-gallery microresonator

Cited by 36 publications

References 20 publications

Nanoscale temperature measurements using non-equilibrium Brownian dynamics of a levitated nanosphere

Nanoscale temperature measurements using non-equilibrium Brownian dynamics of a levitated nanosphere

Whispering gallery mode sensors

Van der Waals Force Assisted Heat Transfer

Contact Info

Product

Resources

About