Near-field photonic cooling through control of the chemical potential of photons.

Photonic cooling of matter has enabled both access to unexplored states of matter, such as Bose-Einstein condensates, and novel approaches to solid-state refrigeration. Critical to these photonic cooling approaches is the use of low-entropy coherent radiation from lasers, which makes the cooling process thermodynamically feasible. Recent theoretical work has suggested that photonic solid-state cooling may be accomplished by tuning the chemical potential of photons without using coherent laser radiation, but such cooling has not been experimentally realized.

Parallelized, real-time, metabolic-rate measurements from individual Drosophila.

Significant recent evidence suggests that metabolism is intricately linked to the regulation and dysfunction of complex cellular and physiological responses ranging from altered metabolic programs in cancers and aging to circadian rhythms and molecular clocks. While the metabolic pathways and their fundamental control mechanisms are well established, the precise cellular mechanisms underpinning, for example, enzymatic pathway control, substrate preferences or metabolic rates, remain far less certain. Comprehensive, continuous metabolic studies on model organisms, such as the fruit fly Drosophila melanogaster, may provide a critical tool for deciphering these complex physiological responses.

Nanogap near-field thermophotovoltaics.

Conversion of heat to electricity via solid-state devices is of great interest and has led to intense research of thermoelectric materials. Alternative approaches for solid-state heat-to-electricity conversion include thermophotovoltaic (TPV) systems where photons from a hot emitter traverse a vacuum gap and are absorbed by a photovoltaic (PV) cell to generate electrical power. In principle, such systems may also achieve higher efficiencies and offer more versatility in use.

A Thermal Diode Based on Nanoscale Thermal Radiation.

In this work we demonstrate thermal rectification at the nanoscale between doped Si and VO surfaces. Specifically, we show that the metal-insulator transition of VO makes it possible to achieve large differences in the heat flow between Si and VO when the direction of the temperature gradient is reversed. We further show that this rectification increases at nanoscale separations, with a maximum rectification coefficient exceeding 50% at ∼140 nm gaps and a temperature difference of 70 K.

Giant Enhancement in Radiative Heat Transfer in Sub-30 nm Gaps of Plane Parallel Surfaces.

Radiative heat transfer rates that exceed the blackbody limit by several orders of magnitude are expected when the gap size between plane parallel surfaces is reduced to the nanoscale. To date, experiments have only realized enhancements of ∼100 fold as the smallest gap sizes in radiative heat transfer studies have been limited to ∼50 nm by device curvature and particle contamination. Here, we report a 1,200-fold enhancement with respect to the far-field value in the radiative heat flux between parallel planar silica surfaces separated by gaps as small as ∼25 nm.

Radiative heat conductances between dielectric and metallic parallel plates with nanoscale gaps.

Recent experiments have demonstrated that radiative heat transfer between objects separated by nanometre-scale gaps considerably exceeds the predictions of far-field radiation theories. Exploiting this near-field enhancement is of great interest for emerging technologies such as near-field thermophotovoltaics and nano-lithography because of the expected increases in efficiency, power conversion or resolution in these applications. Past measurements, however, were performed using tip-plate or sphere-plate configurations and failed to realize the orders of magnitude increases in radiative heat currents predicted from near-field radiative heat transfer theory.

Enhancement of near-field radiative heat transfer using polar dielectric thin films.

Thermal radiative emission from a hot surface to a cold surface plays an important role in many applications, including energy conversion, thermal management, lithography, data storage and thermal microscopy. Recent studies on bulk materials have confirmed long-standing theoretical predictions indicating that when the gap between the surfaces is reduced to tens of nanometres, well below the peak wavelength of the blackbody emission spectrum, the radiative heat flux increases by orders of magnitude. However, despite recent attempts, whether such enhancements can be obtained in nanoscale dielectric films thinner than the penetration depth of thermal radiation, as suggested by theory, remains experimentally unknown.