Search

The common methods used for correcting chromatic aberration are typically based on multi‐lens and multi‐material systems, resulting in lens thicknesses that are several orders of magnitude greater than the wavelength and complex combination designs. A method to achieve the singlet achromatic microlens of the wavelength‐scale thickness by utilizing high refractive index materials with an aspherical profile is proposed. A theoretical model based on the dispersion effect is developed to guide the selection of materials and the design of thicknesses for achieving chromatic aberration correction in singlet microlenses of a given diameter and numerical aperture. H‐ZLaF68N (68N) glass, sapphire, and fused silica with relatively high to low refractive index are selected to prepare the singlet achromatic microlenses to verify the validity of the model. The thicknesses of three microlenses are 573, 737 nm, and 1.27 µm, respectively, and all of them have achieved achromatic correction as designed. This indicates that the high refractive index material not only achieves achromatic aberration but also reduces the thickness by ≈50% compared with the conventional low refractive index material of silica glass. The presented wavelength‐scale singlet achromatic microlens hold significant promise for compact wearable devices, dynamic holography, and color projection displays. [ABSTRACT FROM AUTHOR]

Development of microelectronic technology is highly desired to address chip power instability and micro-overheating in highly integrated devices utilizing a single material. For this purpose, we propose an efficient strategy by using a ferroelectric thin film to achieve the multifunction of chip power and thermal management. The Pb0.91La0.06Zr0.8Ti0.2O3 (PLZT) thin films undergo nucleation and growth in the (100) preferred orientation on the LaNiO3 bottom electrode during the layer-by-layer annealing process. The obtained chorogi-like structure with both lamellar and columnar nanocrystals results in a high breakdown strength of 4224 kV cm−1, accompanied by an exceptional recoverable energy storage density (Wrec) of 43.20 J cm−3. A large adiabatic temperature change (ΔT) of 27.25 K (@2000 kV cm−1) is obtained near the depolarization temperature, and the broad temperature span (80% ΔTmax) is larger than 50 °C. Moreover, PLZT thin films demonstrate a pyroelectric coefficient (π) of −145 μC cm−2 K−1 with high temperature stability, whose excellent thermal detection capability is confirmed by the infrared response measurement. Above all, the excellent energy storage, electrocaloric effect and pyroelectric properties of the PLZT thin films make them highly promising to inhibit the damage of abrupt current/voltage and uneven heat dissipation for applications in chip power and thermal management. [ABSTRACT FROM AUTHOR]

As an important method of image processing, image differentiation enables edge detection of targets to achieve recognition of object features and information compression and the computation speed can be boosted by optical information techniques. Traditional optical image differentiation methods mainly rely on spatial spectrum filtering by using classical 4f system, while some work focus on 1D or single‐direction differentiation. It is only in recent years that the rapid development of metasurfaces has facilitated image differentiation methods. In this work, a Laplace operation device is demonstrated based on a silicon hollow brick dielectric resonant metasurface for incident light field. The optical transfer function (OTF) required by the optical Laplace operation can be obtained by exciting an angularly selective toroidal dipole (TD) resonance supported by the metasurface. This hollow silicon brick differentiator not only realizes 2D second‐order edge detection but also has a numerical aperture close to 0.4 and a broad working wavelength range >100 nm and can be directly integrated with imaging systems. Such metadevice may be potentially applied in the fields of optical sensing, microscopy, machine vision, biomedical imaging, etc. [ABSTRACT FROM AUTHOR]