Fig. 4

Manipulation of near-field radiation by modifying surface condition with MD multilayers. a Measured near-field radiative heat flux between MD multilayers (f = 0.1, 3 Ti/MgF₂ unit cells) with respect to the submicron vacuum gap distance (emitter temperature: 400 K and receiver temperature: 300 K). Theoretical results of near-field thermal radiative heat flux between multilayered structures that are computed considering multiple reflections in multilayer (i.e., exact computation) or effective medium theory (EMT), as well as between bulk Ti media, are plotted. The inset shows the near-field radiative heat flux plotted on log scale. Calculated near-field radiative heat flux between bulk MgF₂ media and far-field radiative heat flux between Ti/MgF₂ multilayers are also plotted. b Near-field radiative heat flux between MD multilayers (f = 0.1, 3 Ti/MgF₂ unit cells) as a function of emitter temperature. The inset is a graph of radiative heat transfer coefficient h_R for all measured data. c Enhanced near-field radiative heat flux between MD multilayers (f = 0.1) with different numbers of unit cells. Emitter temperature is set to 370 K. d Tuning of near-field radiative heat flux by changing of volume filling ratio of MD multilayer, f (3 Ti/MgF₂ unit cells). The near-field radiative heat flux is measured at an emitter temperature of 370 K. The error bars in a–d represent the combination of the measurement uncertainty and standard deviation of multiple measurements (Supplementary Note 11)