# Fundamental Limits to Near-Field Optical Response over Any Bandwidth

@article{Shim2019FundamentalLT, title={Fundamental Limits to Near-Field Optical Response over Any Bandwidth}, author={Hyungki Shim and Lingling Fan and Steven G. Johnson and Owen D. Miller}, journal={Physical Review X}, year={2019} }

We develop an analytical framework to derive upper bounds to light--matter interactions in the optical near field, where applications ranging from spontaneous-emission amplification to greater-than-blackbody heat transfer show transformative potential. Our framework connects the classic complex-analytic properties of causal fields with newly developed energy-conservation principles, resulting in a new class of power--bandwidth limits. These limits demonstrate the possibility of orders-of…

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