Microelectromechanical system (MEMS) mirrors scan light beams and are used in displays and imaging devices in various environments. In particular, in recent years, their application in light detection and ranging has been promoted for autonomous driving of transportation equipment. The driving characteristics of MEMS mirrors are influenced by the driving environment and various physical parameters, especially the temperature. Therefore, developing driving methods that are less affected by the driving environment is necessary. Recently, data-driven artificial neural networks (ANNs) that can extract outputs from various input parameters have also been investigated. Therefore, we propose an operational method for temperature compensation using an ANN for MEMS mirrors. Multiple temperature sensors were installed on a circuit board mounted on a commercially available MEMS mirror to measure the temperature of the operating environment. A dataset was obtained to train and test the constructed ANN. The ANN-based driving method was compared with that using the least-squares method. In addition, the time required to update the parameters in the setup used in this study was investigated.

We introduce the concept and realization of a miniaturized holographic twin trap for optical trapping of microparticles. The hybrid refractive–diffractive microlens, manufactured on a glass slide by two-photon lithography, generates two axially separated foci, which are superposed by a mirror to obtain a counterpropagating trap. We present the optical design and an optimization strategy to balance the intensities of the zeroth- and first-order foci of the manufactured microlenses. Furthermore, we apply our approach experimentally and demonstrate stable trapping of 3 μm polystyrene beads in water.

The integration of phase change materials (PCMs) with photonic devices creates a unique opportunity for realizing application-specific, reconfigurable, and energy-efficient photonic components with zero static power consumption and low thermal crosstalk. In particular, photonic waveguides based on silicon or silicon nitride can be integrated with PCMs to realize nonvolatile photonic memory cells, which are able to store data in the phase state of the PCMs. We delve into the performance comparison of PCM-based programmable photonic memory cells based on silicon photonic and silicon nitride platforms using known PCMs (GST and GSST) for photonic memory applications while showcasing the fundamental limitations related to each design in terms of the maximum number of bits that they can store as well as their optical insertion loss. Moreover, we present comprehensive design-space exploration for analyzing the energy efficiency and cooling time of the photonic memory cells depending on the structure of the heat source. The results show that the silicon-based strip waveguide integrated with GST is the best option to realize a photonic memory cell with the highest bit density (up to 4-bits per cell given 6% spacing between the optical transmission levels). In addition, considering a microheater integration on top of a waveguide on which PCM is deposited, multi-physics simulation results show that as the heat source is placed above the PCM with a gap of 200 nm, the photonic memory cell tends to become more energy-efficient, and the cooling time of the PCM (for set and reset) becomes significantly shorter than the case where the heat source is placed further from the PCM.

Metasurfaces have attracted immense interest across various scientific disciplines due to their ability to manipulate light wave parameters with numerous functionalities. However, these functionalities have historically been static, lacking the capability for dynamic, real-time control. In this study, we introduce a highly efficient, tunable waveplate by incorporating a thin layer of the phase change material Sb2Se3 into a silicon all-dielectric metasurface. This structure demonstrates the ability to transition from a half-waveplate to a quarter-waveplate as Sb2Se3 shifts from an amorphous to a crystalline state at the telecom wavelength of 1.55 μm. Remarkably, it maintains consistent performance across a range of rotation angles. In addition, we have performed comprehensive electro-thermal simulations to validate the phase change process, confirming the practical feasibility of this technology. This tunable metasurface represents a significant advancement in adaptive photonics, offering customizable and sophisticated functionalities.

has been widely used to integrate photonic components, such as lasers, modulators, photodetectors, micro-LEDs, on Si photonic platforms. There is a push toward the μTP of optical components in photonics packaging as it enables wafer-scale integration with high alignment accuracy. We demonstrate for the first time the μTP of thick optical components, such as micro-lenses, in the range of 250 to 1000 μm thickness. We explore the reliability of bonding such components using an ultraviolet (UV) curable epoxy and compare them with the current state of the art. The results show that the average shear strength of lenses bonded with InterVia is 19 MPa which is higher than currently used optical epoxies. Also, μTP process has no effect on the surface roughness and microstructure of lenses. Using our approach, we demonstrate how thick silicon and fused silica lenses can be integrated into photonic integrated circuits (PICs) using a tether-free process that is highly scalable and robust.

Nanoimprinting of surface-relief grating-based waveguides has the potential to produce one of the industry-leading augmented reality (AR) smart glasses, but there are still many challenges in the design, scaling, and reproducibility of these imprinted waveguides. A promising path toward mass manufacturing of optical waveguide combiners is via large-area nanoimprinting. Here, we present the complete value chain with partners involved throughout the process: from design, mastering, and materials to imprinting and metrology, to prove that this method improves not only the manufacturing throughput but also the waveguide quality. We demonstrate that the replication and image quality are true to the intended design using large area, high refractive index (n ¼ 1.9), square (300 mm × 300 mm) glass substrates with high-refractive index resins (n ¼ 1.9). This is shown to be valid for over 100 replications and for large area nanoimprinting (Gen5, 1100 mm × 1300 mm). Our goal is to demonstrate a viable path toward high-volume and low-cost manufacturing of AR waveguides based on surface relief gratings.

In this work, two-photon polymerization three-dimensional laser writing is used to integrate a microlens on the surface of a single mode polarization-stable verticalcavity surface-emitting laser (VCSEL) to be used as a current-driven tunable source in a compact optical guided-wave gas sensor. The writing conditions are optimized to enable on-demand room temperature and single-step fabrication at a post-mounting stage. We show that a writing time of 5 min is sufficient to fabricate a microlens that efficiently reduces the VCSEL beam divergence, without significant change on its emitted power or polarization stability. The lens addition reduces the spectral available range at high injection currents. A two-dimensional optical modeling of the gain characteristics is used to explain this effect and a new transverse design is proposed to avoid this issue.

Endomicroscopy is a technique to visualize microscopic structures of internal tissues through tubular instruments that can be inserted through a small cut or an opening in the body. There has been a growing demand for miniaturizing endoscopic instruments while preserving a high resolution to achieve a real-time histopathologic diagnosis. Meanwhile, there has recently been tremendous progress in the coherent manipulation of light in which an optical wave is deterministically manipulated through a linear, disordered medium for optical focusing and imaging. Here, we review recent research efforts in developing new endomicroscopic imaging schemes based on the coherent formulation and manipulation of optical fibers. In contrast to the conventional schemes using optical fibers as incoherent channels for optical power, these approaches provide a route to fully exploiting useful information transmitted through an ultrathin probe, thereby potentially achieving practical endomicroscopic imaging through a submillimeter thick probe.

JOM Associate Editor Dr. Hui Min Leung of Harvard Medical School and Massachusetts General Hospital interviews Dr. Guillermo (Gary) Tearney, the Remondi Family Endowed MGH Research Institute Chair, Professor of Pathology at Harvard Medical School, and an Affiliated Faculty member of the Harvard-MIT Division of Health Sciences and Technology. He maintains a lab at the Wellman Center for Photomedicine at the Massachusetts General Hospital. With the use of advanced endomicroscopy technologies, Tearney’s lab performs development and clinical validation of non-invasive, high-resolution optical imaging methods for human disease diagnosis. Through this interview, he described how he got into the field and how important and relevant optical microsystems are to those research projects. He also gave his thoughts on the future of the field and the grand challenges that remain to be tackled.