Design and full analysis of a metafiber-based photothermal bio-probe with perfect conversion efficiency

Abstract The metafiber, which involves fabricating metasurfaces at optical fiber tips, has shown potential as an integrated optical sensing or photothermal conversion platform. In this study, we present a metafiber-based photothermal bio-probe with a high optical absorption efficiency of 99.83%. Physical mechanisms underlying the efficiency are elucidated using coherent perfect absorption and multiple reflection theories. In our simulation, the probe exhibits ultra-fast heating/cooling rates, high temperature localization, steep temperature gradients, and robust response to environmental factors. In particular, only 1.0 mW of incident power is needed to generate the temperature gradient required for cell capture or drug delivery, while the corresponding temperature near the fiber tip is still safe for biological tissue. These advantages make our designed bio-probe as an ideal platform in various of applications, such as living cells capture, drug delivery, and local hyperthermia.