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Main Authors: Li, Zhenpeng, Degeorges, Mathis, Varghese, Nithin Jo, Mandal, Jyotirmoy
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2603.02513
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author Li, Zhenpeng
Degeorges, Mathis
Varghese, Nithin Jo
Mandal, Jyotirmoy
author_facet Li, Zhenpeng
Degeorges, Mathis
Varghese, Nithin Jo
Mandal, Jyotirmoy
contents A surface that selectively emits heat in the long-wave infrared (LWIR) can enable passive cooling in hot environments while retaining partial radiative insulation in cold conditions. However, its cost-effectiveness, practical deployment, and fundamentally, the optical design, remain limited by the reliance on metal reflectors. To overcome this limitation, here we use an absorption-scattering competition factor to establish design guidelines for enhancing reflection or absorption in disordered media across the ultrabroadband ultraviolet-to-far-infrared range. Based on electromagnetic simulations and the optical constants of real materials, we then propose disordered photonic media with a layered, multiscale scattering architecture which, unlike typical scattering designs, simultaneously attains ultraviolet-to-far-infrared reflection and selective LWIR emission. We validate this approach by developing a metal-free selective emitter that exhibits high LWIR emittance (0.88), strong solar reflectance (0.97), and low thermal emittance outside the LWIR (0.49), independent of substrates. Field tests, supported by theoretical modelling, show both enhanced radiative cooling and seasonal thermoregulation performance relative to a state-of-the-art broadband radiative cooler. By expanding the spectral functionality of disordered scattering media as a scalable and low-cost optical materials platform across the solar-to-thermal infrared waveband, this work provides a pathway towards improved energy savings and thermal comfort through passive radiative thermal management.
format Preprint
id arxiv_https___arxiv_org_abs_2603_02513
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Disordered Photonic Medium Enabling Ultrabroadband Light Scattering and Selective Longwave Infrared Emission
Li, Zhenpeng
Degeorges, Mathis
Varghese, Nithin Jo
Mandal, Jyotirmoy
Optics
Applied Physics
A surface that selectively emits heat in the long-wave infrared (LWIR) can enable passive cooling in hot environments while retaining partial radiative insulation in cold conditions. However, its cost-effectiveness, practical deployment, and fundamentally, the optical design, remain limited by the reliance on metal reflectors. To overcome this limitation, here we use an absorption-scattering competition factor to establish design guidelines for enhancing reflection or absorption in disordered media across the ultrabroadband ultraviolet-to-far-infrared range. Based on electromagnetic simulations and the optical constants of real materials, we then propose disordered photonic media with a layered, multiscale scattering architecture which, unlike typical scattering designs, simultaneously attains ultraviolet-to-far-infrared reflection and selective LWIR emission. We validate this approach by developing a metal-free selective emitter that exhibits high LWIR emittance (0.88), strong solar reflectance (0.97), and low thermal emittance outside the LWIR (0.49), independent of substrates. Field tests, supported by theoretical modelling, show both enhanced radiative cooling and seasonal thermoregulation performance relative to a state-of-the-art broadband radiative cooler. By expanding the spectral functionality of disordered scattering media as a scalable and low-cost optical materials platform across the solar-to-thermal infrared waveband, this work provides a pathway towards improved energy savings and thermal comfort through passive radiative thermal management.
title A Disordered Photonic Medium Enabling Ultrabroadband Light Scattering and Selective Longwave Infrared Emission
topic Optics
Applied Physics
url https://arxiv.org/abs/2603.02513