Abstract
Liquid properties in nanochannels are one of the important issues in nanofluidics. In this study, a new method to investigate thermal diffusivity in nanochannels is proposed. Our detection method, photothermal optical phase shift (POPS), was modified to allow thermal diffusivity measurement: thermal diffusion POPS (TD-POPS). As a result, thermal diffusivity of water was successfully measured in a 400 μm wide and 500 nm deep nanochannel.