Phys.org October 28, 2024
Unidirectional imagers form images of input objects only in one direction. Researchers at UCLA reported unidirectional imaging under spatially partially coherent light and demonstrated high-quality imaging only in the forward direction (A → B) with high power efficiency while distorting the image formation in the backward direction (B → A) along with low power efficiency. Their analyses revealed that when illuminated by a partially coherent beam with a correlation length of ≥∼1.5λ, where λ was the wavelength of light, diffractive unidirectional imagers achieved robust performance, exhibiting asymmetric imaging performance between the forward and backward directions. A partially coherent unidirectional imager designed with a smaller correlation length still supported unidirectional image transmission but with a reduced figure of merit. These partially coherent diffractive unidirectional imagers were compact, polarization-independent, and compatible with various types of illumination sources, making them well-suited for applications in asymmetric visual information processing and communication… read more. Open Access TECHNICAL ARTICLEÂ
Concept of a unidirectional diffractive imager with partially coherent illumination… Credit: Adv. Photon. Nexus , Volume 3, Issue 6, 26 October 2024