ODS 2024: Industrial Optical Devices and Systems

In this era of digital advancement, securing communication and data has become crucial. Nanophotonic metasurfaces have shown great potential in light manipulation, but they are limited in spectral range and wavelength handling. This limitation hampers their effectiveness in optical imaging and information encryption, where broader spectral coverage and multiple resonant peaks are desired. We propose an innovative approach to address these challenges. Our multi-resonant high-Q metasurface platform integrates subwavelength plasmonic meta-atoms with a specially designed DBR substrate. This platform enables simultaneous excitation of multiple high-Q resonant modes across a broad spectrum. Through optimizing the nanostructures, the metasurface can support up to 15 high-Q peaks without compromising operational efficiency. To demonstrate our platform's performance, we present two practical applications. The first is a hyperspectral imaging system using a single multi-wavelength metasurface chip. The second application combines structural color printing and vectorial holographic imaging for advanced optical information encryption, leveraging our platform's capabilities.

The manipulation of focused light beams is widely used in our lives, such as camera lenses and signal transmission. Although there are traditional lenses that realize off-axis focusing, the requirements of tilting need extra space, and the tilting stage hinders its compact integration. These disadvantages hinder the development of device miniaturization or increased construction complexity. Meta-devices composed of artificial nanostructures can manipulate the incident electromagnetic wave's phase, polarization, and amplitude. Meta-devices show excellent performance and novel applications to meet optical demands. The significant advantages of meta-devices are their new properties, lighter weight, and compact size. Here, we demonstrate cascaded meta-devices for focal length tuning in the z-axis (1-dimensional, 1D), focal spot manipulation in the x-y plane (2-dimensional, 2D), and x-y-z axis (3-dimensional, 3D). The varifocal meta-devices are used for bioimaging and 6G signal transmission.

The data increase necessitates high-capacity, low-energy optical data storage. Bridging the memory gap between units and processors requires techniques and materials mimicking the efficiency of the human brain’s memory based on synaptic plasticity. Optical techniques show promise, yet energy-efficient optical data storage compels advanced media. Upconversion nanoparticles are luminescent nanomaterials for high-capacity, low-energy optical data storage. We used upconversion nanoparticles for ultra-low-energy optical data storage with synaptic-like behaviour by switching upconversion states under low light power irradiation. We achieved features with sub-nanojoule-level energy consumption and synaptic-like functions of the human brain’s memory, enabling short-term and long-term memory.

Along with the rapid development of information technology such as cloud computing, Internet of Things and artificial intelligence etc., huge amount of data is growing at an explosive rate. Conventional optical storage technics are promising candidates for massive data storage. However, they have limited storage capacities because the recording spot cannot be minimized under the diffraction limit. Here, we demonstrate nanoscale optical memory based on a photoresist film. And our nanoscale optical memory has the potential to hold as much data as a large petabyte-level HDD library.

Heat-assisted magnetic recording (HAMR) is a promising technology for improving the recording density of hard disk drives. A near-field transducer (NFT), which forms a small light spot on a recording medium, is necessary in HAMR. We previously proposed a novel device, in which a metal nano-antenna as an NFT is attached to a semiconductor ring resonator as a light source. In this study, the temperature rise including the recording medium using this device was numerically simulated. It was found that the temperature rise of nano-antenna can be significantly reduced while heating the recording medium sufficiently by optimizing the nano-antenna structure.

Adaptive optics normally concerns the feedback correction of phase aberrations. Such correction has been of benefit in various optical systems, with applications ranging in scale from astronomical telescopes to superresolution microscopes. Here we extend this powerful tool into the vectorial domain, encompassing higher dimensional feedback correction of both polarisation and phase. This technique is termed vectorial adaptive optics (V-AO). This technique pushes the boundaries of traditional scalar beam shaping by providing feedback control of extra vectorial degrees of freedom. This paves the way for next generation AO functionality by manipulating the complex vectorial field.

Our report details a novel approach using polarization holography for the precise detection of vector vortex beams' (VVBs) polarization distribution. We will discuss multiple methodologies facilitated by this technique, offering insights into VVBs' characterization. Upon successful detection, we extract the VVBs' polarization states, allowing for their accurate placement on the Poincaré sphere. The obtained results affirm polarization holography's potential as an effective alternative to conventional measurement methods. This advancement propels polarization holography towards widespread adoption in optical component processing.

Optical quantum devices are promoting the development not only of communication but also of quantum computation using optical quantum gates. Here, we will explain how to replace circuits consisting of gates such as NOT, AND, and OR used in classical logic calculations with quantum calculation gates. Then, we perform reverse tracing of a quantum circuit constructed using the reversibility of quantum gates. As a simple example, we will explain how to perform factorization by backtracking a multiplier expressed as a quantum circuit.

We have developed flexible and stretchable terahertz/infrared imaging sheets with carbon nanotube films [1-4]. We report on multi-view terahertz/infrared visualization, which have enabled us to fully image both the whole outer and inner surface of various objects. We show several examples of omnidirectional terahertz/infrared imaging inspections in a non-destructive and non-contact manner. References: [1] D. Suzuki et al., Nature Photonics 10, 809 (2016). [2] K. Li et al., Nature Communications 12, 3009 (2021). [3] K. Li et al., Science Advances 8, eabm4349 (2022). [4] K. Li et al., Advanced Optical Materials, early view, 2302847 (2023).

We propose a wide FOV aspherical glass MLA for high power Flash LiDAR applications. The proposed MLA combines high power endurance, transmittance, and reliability, overcoming the drawbacks of polymer on glass MLA. We investigated the maintenance of a flat-top intensity distribution in the output beam, noting that the aspherical MLA's divergence angle must surpass the VCSEL's divergence angle. Additionally, we also developed and verified the wide FWHM of the aspherical glass MLA, which manipulated through microlens aspect ratios and pupil ratio design. This innovative device enhances Flash LiDAR performance for long-range ranging.

We have been developing a stereo camera whose field of view is 360 degrees consisting of three hyperbolic mirrors and a single camera, which makes this camera compact and inexpensive. The hyperbolic mirrors enable the omnidirectional view and combining three of them makes it possible to obtain images from two different view points, which are used to measure distances based on the stereo-vision principle. By adopting a radiation tolerant camera (250 kilo pixels) as the single camera, this stereo camera becomes a sensing device suitable for robot operation in harsh radiation environments. The prototype is ~360 millimeters tall and the distance error less than 5%. In this talk, we present the optical system and the prototype of the omnidirectional stereo camera as well as procedures to obtain the image and distance information.

Potential of diffraction grating formed inside a transparent medium generated by sound wave is investigated for display applications. The typical range of surface deformation and index modulation is calculated.

Deflectometry is an established technique in optical metrology used for ultra-precise 3D measurements of specular surfaces. This talk will discuss how deflectometric information can be utilized for novel eye-tracking methods that evaluate the gaze direction in single-shot with high accuracy. Potentials and limitations of different flavors will be discussed.

Today’s manufacturing processes, especially 3D printing with powder or wire, presuppose Industry 4.0 solutions, which require supervision of every single production step. Transforming machine elements into intelligent cyber-physical systems involves the integration of smart sensors for condition and process monitoring. As photonic solutions are by nature contact-free processes it would be advantageous if the sensor is based on light as well, if the light could be coupled into the beam path of the processing laser and if the sensor can measure surface topography in micrometer resolution. In this case, the production process can be directly connected to the CAD data set, the process could be controlled to eliminate geometrical deviations to the desired geometry and first-time-right is not a pious hope anymore. We talk about controlled individualized lot size 1 production based on OCT sensor technology.

Reflective Micro Electro Mechanical System (MEMS) display as a spatial light modulator with synchronized nano-second pulse effectively diffracts light into one of multiple diffraction orders with high efficiency. Beam and image steering in a time sequential manner by this principle is applied for optical systems such as lidar, near-to-eye display and high-framerate cameras. We overview diffractive MEMS based beam and image steering by using a concept Time-to-Angle Conversion.

A wavelength and time multiplexed image transfer by employing multiple light sources and volume hologram grating expands the field-of-view of the image guide combiner for near-to-eye beyond its total internal reflection limit.

This talk will consider the future of metal halide perovskite (MHP) photovoltaic (PV) technologies as photovoltaic deployment reaches the terawatt scale. The requirements for significantly increasing PV deployment beyond current rates and what the implications are for technologies attempting to meet this challenge will be addressed. In particular how issues of CO2 impacts and sustainability inform near and longer-term research development and deployment goals for MHP enabled PV will be discussed. To facilitate this, an overview of current state of the art results for MHP based single junction, and multi-junctions in all-perovskite or hybrid configurations with other PV technologies will be presented. This will also include examination of performance of MHP-PVs along both efficiency and reliability axes for not only cells but also modules placed in context of the success of technologies that are currently widely deployed.

The recent advent of robust, refractory (having a high melting point and chemical stability at temperatures above 2000°C) photonic materials such as plasmonic ceramics, specifically, transition metal nitrides (TMNs), MXenes and transparent conducting oxides (TCOs) is currently driving the development of durable, compact, chip-compatible devices for sustainable energy, harsh-environment sensing, defense and intelligence, information technology, aerospace, chemical and oil & gas industries. These materials offer high-temperature and chemical stability, great tailorability of their optical properties, strong plasmonic behavior, optical nonlinearities, and high photothermal conversion efficiencies. This lecture will discuss advanced machine-learning-assisted photonic designs, materials optimization, and fabrication approaches for the development of efficient thermophotovoltaic (TPV) systems, lightsail spacecrafts, and high-T sensors utilizing TMN metasurfaces. We also explore the potential of TMNs (titanium nitride, zirconium nitride) and TCOs for switchable photonics, high-harmonic-based XUV generation, refractory metasurfaces for energy conversion, high-power applications, photodynamic therapy and photochemistry/photocatalysis. The development of environmentally-friendly, large-scale fabrication techniques will be discussed, and the emphasis will be put on novel machine-learning-driven design frameworks that leverage the emerging quantum solvers for meta-device optimization and bridge the areas of materials engineering, photonic design, and quantum technologies.

Mechanically induced long-period gratings (MILPGs) in wide range of optical fibers including standard single-mode fiber (SMF-28), double-cladding fibers like Thorlabs DCF-13 and, Nufern S-1310, P-doped, and photonic crystal fiber (PCF) will be presented. To this aim, high-resolution 3D printing technique, stereolithography (SLA), has been used to fabricate grooved plates for mechanically inducing LPG. Several factors including effect of weight, grating length, polarization -dependence and fiber coating were considered to assess the performance of fabricated MILPGs devices and these devices exhibit superior spectral characteristics including negligible power losses and well-defined narrow attenuation bands. The proposed fabrication technique stands out for its cost-effectiveness and easiness. Furthermore, a wide range of optical fibers were explored in this study and the findings suggest potential applications in sensing and communication. This marks the first extensive investigation of MILPGs in the explored fibers, indicating a novel contribution to the field.

The lighting industry continues to adopt the 3D Printers to use in many aspects of their product design and development. From prototypes of lighting fixtures to custom tools to assist in the manufacturing process to creating clear lenses with additive manufacturing technologies. This presentation will show use cases in the lighting industry and the exciting advances in the 3D World.

In recent years, sustainability has anchored itself as a central and critical concern for manufacturing. Additive manufacturing offers some unique aspects, and this technology opens up significant renewable and sustainable opportunities. In addition to the environmental advantage, this process also unlocks some additional benefits, by offering the ability to work within different boundaries and further push the limits of manufacturing. This presentation will mainly focus on the sustainable and renewable aspects, showcasing how this technology enables the use of materials that were once considered waste. We will conclude by discussing how these custom materials allows the fine tuning of material properties, allowing us to tweak both visual and mechanical properties and create some unique, eco-friendly products.

This work focuses on an App that examines the birefringence of different solutions. Its structure involves directing laser light through an initial polarizer, then through a crystal containing an optically active solution. The polarized light travels to another polarizer designed to automatically rotate 360 degrees, and the resulting power is captured at each degree through an optical fiber connector. The signal is processed and sent in real-time to a mobile device application using an internet connection, where it is stored and further processed. With this setup, users can process data, store it securely, and adjust settings in an intelligence virtual physics laboratory.