Thermal radiative energy transport plays a pivotal role in energy harvesting as well as thermal management applications. One approach for tailoring the optical properties that mediate radiative transfer is laser processing. However, efforts to date have largely focused on improving absorption in a relatively narrow spectral ranges up to near-infrared wavelength (< 2.5 μm). Accordingly, new approaches are sought to specifically extend the range into the mid-infrared (2.5 to 15 μm) to improve light absorption and thermal stability. All these properties are not currently attainable by any alternative technique, including the use of carbon materials or applying surface coatings.


We demonstrate laser-induced broadband emitters (LIBEs) with spectral emissivity higher than 0.96 from 0.3 to 15 μm in wavelength, aimed at enhancing thermal radiative energy transport on different types of substrates (metals, metal alloys, and carbon materials). Localized material removal induced by ultrafast femtosecond laser irradiation results in the hierarchical formation of microstructures decorated with micro-/nano- particles. Similar surface geometries can be obtained on different types of substrates under nearly consistent experimental laser processing parameters. Finite-difference time-domain simulations demonstrate that the mesoscale morphology can confine and absorb the incident light between the recessed areas inside microcavities, leading to an enhancement in a spectral absorptivity close to 1. Moreover, LIBEs can maintain their enhanced spectral absorptivity of 0.92 after heating at elevated temperatures above 1273K for over 100 hours. Our results provide insights into the use ultrafast laser-matter interactions for cutting-edge energy harvesting and thermal management applications.