Editor-in-Chief Hans Zappe announces the journal’s move to a hybrid access model.

Selecting micro-electromechanical actuators with high force output, broad traveling ranges, and robust reliability becomes increasingly critical for active optical microsystem devices. We offer a comparative analysis of electrostatic comb actuators tailored for optical applications, focusing on evaluating performance for the demands of force density, traveling range, and footprint. Previous analyses often examined force generation in isolation, without a comprehensive assessment of these actuators’ footprint efficiency and practical traveling range. By integrating these parameters, we provide new insights into the suitability of various electrode designs for optical microsystems, thus offering a broader perspective on actuator selection. Our analysis particularly emphasizes silicon platforms with a dedicated microelectromechanical system layer, where optical waveguides are fabricated on top, resulting in enhanced mechanical stability and reliability. We delve into the implications of different configurations, considering the delicate balance between maximizing force, minimizing footprint, and maintaining operational travel range. Our findings reveal that actuators combining gap-closing and area-overlap mechanisms achieve superior performance by covering a larger range of force densities and traveling ranges with lower actuation voltages. This design excels in both small and large traveling ranges and is a strong candidate for photonic applications requiring high force and large traveling ranges within a compact footprint. In addition, we present a comprehensive map of the operational regimes for each actuator type, enabling a targeted selection based on the specific requirements of photonic applications. We aim to assist in microelectromechanical actuator designs for optical microsystems, empowering designers to make informed decisions for electrode configurations that meet the nuanced demands of specific optical microsystem applications.

As semiconductor wafer process technology advances, there is a notable miniaturization of complementary metal-oxide-semiconductor transistors, allowing for a higher transistor density on the predominant 12-in. silicon wafers. Despite this trend, a significant number of applications remain tethered to legacy wafer sizes such as 8 in., 6 in., or even smaller. Economically packaging these devices presents a challenge. Furthermore, many of these applications necessitate that the active surface remains exposed to external environments, contrasting with conventional packaging methods that shield the active surface with epoxy molding compounds. Addressing these specialized needs, we introduce a “chip-first face-up wafer-level fan-out packaging.” This innovative approach ensures that the active surface remains outward-facing and accessible for intended interactions with the environment while concurrently enabling electrical connections from the chip to the board on the side opposite to the active surface through the meticulous combination of redistribution layers and through-silicon vias.

Tunable liquid micro-optical lenses and phase shifters based on multi-electrode electrowetting actuation are often subject to wavefront errors due to processing irregularities or surface defects. To enable the correction of these anomalies, we present here a method that allows calibration and compensation for wavefront errors, thereby leading to the best possible optimization of the tunable optical surface. The approach relies on a measurement of the transmitted wavefront using a Shack–Hartmann sensor and subsequent determination of the actual surface shape. The deviation between this and the target surface shape is calculated, and the electrode voltages are iteratively adjusted. A decentralized control algorithm is implemented which treats the meniscus height at each electrode as a variable with independent feedback; an adaptive update condition determines which electrodes should be adjusted in each cycle. Experimentally obtained calibration curves for a 32-electrode device demonstrate the power and utility of the method.

We investigate a graphene and vanadium dioxide (VO2)-based planar antenna with higher-order transverse magnetic (TM) mode for terahertz (THz) applications. The planar antenna is made up of graphene and VO2 materials. Adding graphene and VO2 makes antenna is even more innovative because it conducts electricity really well and makes the antenna more robust and better in performance. The proposed antenna is excited by proximity coupling with Y shape structure. The planar configuration offers single-band operation with resonant frequency 2.98 THz. The proposed antenna provides a maximum directivity of 9.1 dBi with better co and cross polarization. Further, it supports TM modes with a number of higher modes based on the placement of its radiating elements. These modes are characterized as TM42, TM64, and TM76, and so on. In addition, parametric analysis is essential to investigate how the changes in the parameters affect the performance of the antenna. The examinations of these dependencies have been carried out. The proposed antenna may play a vital role in the THz applications such as biomedical and medical imaging applications which often require precise and high-resolution imaging capabilities that THz frequencies provide.