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Coherent perfect absorption (CPA) dependent on orbital angular momentum (OAM) has been proposed theoretically but so far has lacked experimental validation. Here, we design an OAM-selective coherent perfect absorber and experimentally validate this intriguing phenomenon. By combining a spiral phase plate, a polarization-conversion metasurface, and a conical cavity, an incident plane wave of linear polarization is converted into cylindrical waves with different OAMs in two dimensions, which impinges on a dual-layer cylindrical absorber composed of a ceramic core and an indium tin oxide (ITO) coating. Experimental results, coinciding well with numerical simulations, confirm the OAM-selective CPA for different OAMs. Our findings offer a practical approach for electromagnetic energy harvesting and sensing at subwavelength dimensions.
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http://dx.doi.org/10.1364/OL.559783 | DOI Listing |
Light Sci Appl
August 2025
School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, China.
Coherent diffractive imaging (CDI), with its lensless geometry and theoretically perfect transfer function, is considered as one of the most promising paradigms to achieve the Abbe resolution limit. However, recent advances on pushing the resolution limit in high-numerical-aperture (NA) CDIs has thus far been challenging. Here, we report a nearly 0.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
August 2025
Department of Ophthalmology, University Hospital Bonn, Venusberg-Campus 1, Bonn, Germany.
Purpose: The purpose of this study was to investigate characteristics of chorioretinal lesions secondary to acute posterior multifocal placoid pigment epitheliopathy (APMPPE) using multi-wavelength fundus autofluorescence (FAF) and their association with intraocular inflammation.
Methods: In this exploratory cross-sectional study, patients with chorioretinal lesions secondary to APMPPE underwent multimodal imaging including FAF with 450 nm, 488 nm, 518 nm, and 787 nm excitation wavelength, color fundus photography (CFP), and optical coherence tomography (OCT). Lesions were graded for FAF and CFP characteristics and inflammatory activity by an experienced image grader and an ophthalmologist.
Biosensors (Basel)
August 2025
College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, China.
Recently, more and more attention has been paid to human health with the rapid development of society. A designed virtual polarizer (VP) can realize multiscale and multi-biomass sensing, including temperature, cancerous cells, and COVID-19. Based on coherent perfect polarization conversion, a certain polarization conversion can be fulfilled within 1.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
IMDEA Materials Institute, Calle Eric Kandel, 2, 289006, Getafe, Madrid, Spain.
Non-Hermitian systems have recently shown new possibilities to manipulate wave scattering by exploiting loss, yet coherent perfect absorption at an exceptional point (CPA EP) remains elusive in acoustics. Here, we demonstrate it based on a two-channel waveguide with compact lossy resonators. We realize imbalanced losses crucial for CPA EP by using active components to independently modulate the non-Hermiticity.
View Article and Find Full Text PDFSci Rep
August 2025
School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran.
We investigate the coherent control of anisotropic surface plasmon polaritons (SPPs) in a symmetric double-layer metal/uniaxial dielectric structure. The directional anisotropy introduced by the uniaxial dielectric enables tunable SPP dispersion, absorption, and propagation characteristics through an external control field. We analyze reflection and transmission spectra, dispersion relations, propagation lengths, and the scattering matrix eigenmodes.
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