Parkinson’s disease (PD) has afflicted numerous patients and troubled countless families worldwide, but an effective therapeutic approach has not been discovered so far. Yet, emerging evidence suggested that photobiomodulation (PBM) can fundamentally delay and inhibit neuronal degeneration, and thus promisingly serve as a non-invasive alternative to conventional drug and surgical treatments. Nevertheless, the light wavelength and spectrum are crucial to PBM. To optimize the spectral formula of photomedicine and reveal photobiological effects, an acute PD model by injecting paraquat into mice abdomen was established in this study. Then, these mice were treated with the narrowband light-emitting diode (LED)-chip light peaked at 670 nm, the broadband phosphor-converted LED light peaked at 840 nm in 600−1000 nm region, and their combination. The results indicate that the PBM is safe, and the combined (narrow 670 + broad 840 nm) light exerted the most potent therapeutic effects. It significantly attenuated oxidative stress levels, enhanced axonal regeneration, protected dopaminergic neurons in the substantia nigra pars compacta (SNpc), preserved striatal neuronal integrity, and improved neuronal morphology and marker expression. Thereby, broadband wavelength through multitarget synergistic therapy helps to improving pathological features and facilitating neural function repair in acute PD mice. However, behavioral validation remains necessary in future studies and further richens the spectrum engineering to PBM.

Renewed interest in near-field thermal radiation stems from its potential in energy harvesting, nanoscale thermal management, and thermophotovoltaics, driving efforts to understand and engineer its fundamental mechanisms. Plasmonic materials are well recognized for their ability to enhance fields proximal to their surfaces; however, detailed quantitative assessment of the field intensity and energy density of thermal radiation in the near field (relative to the far field) and potential practical impact is lacking. This work presents a detailed study of a prototypical metamaterial design supporting plasmon resonance in the mid-infrared spectrum. Significant intensification of thermal radiation in near field is investigated using a numerical finite-difference time-domain method that incorporates randomly fluctuating dipoles in accordance with the fluctuation-dissipation theorem that enables excitation of high-order spatial harmonics. Electromagnetic response of the metamaterial thermal emitter to both thermal and optical excitations is evaluated and compared. Findings indicate that the near field intensity at a mere 500 nm from the metamaterial surface exhibits an enhancement of up to 38-fold in near-field electromagnetic energy density relative to the corresponding far-field value at 4.8 μm lying near the edge of Brillouin zone under thermal excitation. In contrast, 6-fold enhancement is observed at 4.35 μm lying near the center of the Brillouin zone under optical excitation. Further, thermal excitation yields a 3.5-fold increase in peak intensity compared to conventional blackbody radiation at 2 μm away from the outermost layer of the metamaterial. Moreover, photothermal simulations further reveal rapid temperature rises exceeding 600 K within nanoseconds under low-power pulsed excitation. These results demonstrate that thermal excitation enables access to dark electromagnetic modes that dominate near-field radiation and highlight the importance of excitation mechanism in designing metamaterial-based thermal photonic devices.

The miniaturization of imaging systems is essential for modern optoelectronics, while traditional bulk optics fundamentally limit integration density. Metasurfaces offer a transformative planar alternative by providing nanoscale control over incident light. However, realizing their full potential requires transitioning from discrete optical components to fully integrated sensing architectures. This review surveys the progressive integration of metasurface with photodetectors and image sensors. We examine the developmental trajectory across three distinct levels: free-space optical path placement, hybrid adhesive mounting and direct monolithic fabrication. Particular emphasis is placed on monolithic architectures and their role in enabling multi-dimensional information extraction. Finally, we discuss emerging challenges in material compatibility and scalable manufacturing to provide clear directions for future ultracompact optoelectronic device development.