This PDF file contains the front matter associated with SPIE Proceedings Volume 11500, including the Title Page, Copyright Information, and Table of Contents.

The ODS has been held as part of SPIE Optics + Photonics since 2014. Formerly, the scope of ODS was optical data storage, but since 2018, it has been extended to industrial optical devices and systems. The new scope includes emerging industrial domains such as automotive, IoT, big data, healthcare, security, etc. We are pleased that the number of papers is increasing in the last three years, and that their areas are expanding from traditional optical data storage to various industrial optical devices and systems. This means that the new scope of ODS has been recognized by optics research and development community in industry. We hope that all of you will enjoy this conference and help make it more attractive in the future.

We design and fabricate a 60 × 60 GaN based achromatic meta-lens array to capture multidimensional optical information of the scene. The working wavelength is from 400 nm to 660 nm which covers the entire visible light range. The highest efficiency of single metalens can be up to 74% at a wavelength of 420 nm, while the average efficiency is approximately 39% over the whole working bandwidth. The light field images and the depth information of objects can be determined by reorganizing the patches of sub-images and calculating the disparity of neighboring sub-images, respectively. The depth information can be used to optimize the patch sizes to render the all-in-focus image without artifacts. Our work provides several advantages associated with light field imaging: elimination of chromatic aberration, polarization selectivity and compatibility of the semiconductor process.

We propose a Light-sheet fluorescent microscopy (LSFM) system with a flat metalens, which is used to replace the bulky illuminating components. The metalens is a diffractive optics elements (DOEs) composed of various gallium nitride (GaN) nanopillar for light-sheet generation, and it can be readily integrated in existing LSFM systems. In contrast to the traditional LSFM system, the metalens-based system is more compact and flexible, and its sectioning capability is comparable to the conventional illumination arm in LSFMs. The live fluorescent-labeled transgenic Caenorhabditis elegans (C. elegans) are exploited to verify the performance of this system. The intensity profile of oocytes in C. elegans with cellular resolution level was obtained.

A single-shot non-interferometric phase retrieval method in holographic data storage is proposed to solve the problems that undetectability for phase by detector directly and unstability caused by interferometric detection. Embedded data are inserted in iterative Fourier transform algorithm to shorten iterations sharply. For avoiding embedded data occupying the code rate, we propose a collinear system to refer to the reference beam, which is always known, as the embedded data. Finally, fast stable phase information reading is realized because of single-shot non-interferometric detection and fast phase retrieval within only several iterations.

Extension of adaptive optics (AO) techniques to future data storage applications requires consideration for light reflected off a diffractive surface. Simulations and experiments are presented to study the efficacy of various wavefront reconstruction methods for examining diffractive samples. Image processing techniques are applied as an alternative to a Shack-Hartmann wavefront sensor. A modified Gerchberg reconstruction algorithm is used to gather wavefront data from multiple image acquisitions at different defocus positions. Furthermore, these multiple images are gathered simultaneously with a single acquisition using the concept of phase retrieval with complex diversity. A computergenerated hologram (CGH) is designed, fabricated, and implemented experimentally for single-shot AO correction.

By replacing mercury lamps with solid-state light sources as the light sources of projectors, advantages such as long-life, mercury-free, instantaneous lighting, and high-color-rendering characteristics can be obtained, but low brightness is a problem. In a solid-state light source projector in which blue semiconductor lasers and a yellow phosphor are combined and the phosphor plane and screen are optically conjugate with each other, if the blue laser beam on the phosphor plane is expanded using a diffusion plate to avoid a decrease in the luminous efficiency of the phosphor, the light utilization efficiency decreases and the light intensity distribution becomes non-uniform on the phosphor plane. In this research, a computer-generated hologram, a free-form element, and a polarizing free-form element were designed as light intensity distribution control elements to improve the above two characteristics. The use of each light intensity distribution control element showed an improvement over the diffusion plate through a numerical simulation.

Some of the recent advances in the image engineering technology are three-dimensional and multi-spectral image acquisition. In order to obtain depth information of objects, many technologies are possible such as stereography, ToF, coded aperture and so on. Optical filters, diffraction gratings and variation of light source are available for multi-/hyperspectral imaging. A simple scheme for realizing those advanced technologies are discussed in this study. The proposed system includes only a monochromatic image sensor and a randomly coded aperture without lenses. The lensless imaging technologies are available not only for conventional image acquisition but also for refocusing method. As a statistical optics approach associating with the random coded aperture, simple imaging optics with diffusers are introduced. Those have been applied to acquire depth information and color images. However, none of the proposal to acquire depth and color information simultaneously has been discussed. The size of the point spread function (PSF) of a randomly coded aperture depends on the depth position of a point source. The inverse function of the PSF can retrieve the image on the corresponding depth position, because PSFs of different depths do not correlate to each other. The different wavelengths lead the different PSFs even for the same depth position. It is caused by the nature of diffraction of the aperture. Because of the nature, the selectivities of depth and wavelength are independent, then the proposed system realizes fourdimensional image acquisition with a deterministic approach by using a designed randomly coded aperture.

Compact and low-cost devices are needed for autonomous driving to image and measure distances to objects 360-degree around. We have been developing an omnidirectional stereo camera exploiting two hyperbolic mirrors and a single set of a lens and sensor, which makes this camera cost efficient. This paper presents a new calibration method for this camera. Based on the original calibration method by Mei and Rives, we improve the calibration accuracy by considering higherorder radial distortion, detailed tangential distortion, an image sensor tilt, and a lens-mirror offset. Our method is applied to our prototype and reduces the root mean square of the calibration accuracy by 1.2 times and 2.2 times for the upper- and lower-view images, respectively. The distance error is less than 8% up to objects 14 meters apart, which is improved more than seven times compared to the original method, although the error is still larger than the target value of 5%. We consider that the remaining calibration error is due to distortion of the glass cylinder and a degraded optical resolution. As future work, we plan to make further improvements in the calibration and optical resolution of the prototype. In addition, a rectification method for cylindrically expanded images needs to be developed.

We are developing projector system with scanning fiber device and its control system. Our novel scanning systems of scanning fiber device provide high resolution, uniform brightness, rectangular display area, which are difficult matters of conventional scanning fiber device. And we have confirmed that scanning fiber device is applicable to some application products such as head mounted display.

Digital Micromirror Device (DMD) is a commercial and mass-produced Micro Electromechanical System (MEMS) spatial light modulator (SLM) consisting of millions of mirrors that spatially modulate lights by switching it between on and off states. Between the on- and off-states, transitional states exist where micromirror changes tilt angle. We report a method to control the transitional time of the mirror array by controlling the pressure of the ambient air. The increased air pressure to 100 psi increases mirrors transitional time by 20%. We also address the possibility of controlling the transitional time electrically.

Using a see-through optical viewer with a prism combiner is an affordable solution for head mounted devices. Free-form surfaces are a general way to correct off-axis aberrations generated by combiners. A glass high index wedge prism is used as a combiner to keep the wedge angle small while maintaining total internal reflection and the combiner becomes thinner. Free-form surfaces, on the other hand, are used in relay lenses to correct off-axis aberrations. The diagonal FOV is 44° and the exit pupil diameter is 4.8 mm. After two optical design using XY and Zernike polynomial, we confirm which free-form expression is superior in aberration correction for the viewer.

A highly sensitive near-infrared spectroscopy technique was developed for remote sensing of concrete structures. We have employed a multichannel Fourier transform spectroscopy to achieve this purpose which use an area sensor instead of an often-used linear sensor. In this study, chloride concentrations on the surface of concrete were evaluated.

Laser triangulation is an optical method for measuring distances to an object. A laser beam is directed towards a measurement surface, and the diffusely reflected light is collected by an imaging system onto a detector. The absolute distance can be obtained by using known geometric relations of the system and the position of the laser spot on the detector. Therefore, a change in the measurement distance results in a corresponding movement of the imaged laser spot, defining the sensitivity of the system in pixels per millimeter. This value depends on the geometrical and optical design of the laser triangulation setup, especially the base distance between the laser and the imaging lens, as well as its focal length. As those parameters also influence the geometric dimensions and the possible measurement range of the device, the sensitivity cannot be increased arbitrarily. Thus, the sensitivity of a standard laser triangulation system is limited to a certain value. In this contribution, structured optical surfaces are applied onto the measurement surface to further increase the sensitivity. Through the spatial modulation of the imaged laser spot intensity distribution, the calculated laser spot displacement is larger than its actual geometrical displacement. This effect is examined through simulations with a bar structure, which leads to an improvement of the sensitivity by a factor of up to 5.7 at a distance of 1 m and a measurement range of 2 mm. Eventually, the concept is proven in measurements and feasible implementations of such a structure are considered.

Measuring the thickness of thin films on a wafer is one of the most important steps for the semiconductor manufacturing process. This paper proposes a vision-based methodology for estimating a film thickness profile of the wafer. The scalability and industrial applicability of obtaining film thickness for the wafer with a small computational cost are demonstrated. Experimental results and numerical simulations are designed for investigating the characteristics of estimated solutions based on multiple representative nonlinear regression methods. The regression models are trained with the training data which consists of image value and thickness value pairs where the thickness value is obtained from the physical metrology system. There is an inevitable trade-off between the accuracy and the computational time in the spectrum-based film thickness measurement system in general, but the performance of the proposed methodology satisfied both the accuracy and the estimation time to a moderate extent.

Monitoring carbon dioxide (CO₂) for carbon capture, gas pipelines, and storage as well as early detection of CO₂ leakage is important to mitigate greenhouse gas emissions and have a high atmospheric concentration for a long lifetime. Moreover, the main cause of the corrosion in natural gas pipelines is owed by CO₂. Therefore, real-time and effective CO₂ monitoring is essential to improve efficiency, reduce pipeline emissions, and improve the economics of the natural gas industry. In this paper, we propose and experimentally demonstrate a distributed CO₂ sensor based on the measurement of evanescent wave absorption by using optical frequency domain reflectometry (OFDR). A coreless fiber is re-coated with tetraethyl orthosilicate (TEOS) through a dip-coating process with well-defined fabrication conditions. Rayleigh scattering OFDR system is optimized to provide high spatial resolution and large dynamic range to trace gas detection. The proposed distributed fiber gas sensor exhibits continuous real-time measurement of CO₂ gas concentrations from 5% to 100% calibrated with nitrogen (N₂) as a background gas. The results provide confidence that the proposed sensing technology represents a novel paradigm and holds a potential tool for the early detection of CO₂ leaks with high sensitivity in a distributed fashion.

A distributed fiber optic chemical sensor with a temperature compensation mechanism is revealed using optical frequency domain reflectometry (OFDR). Distributed chemical sensing has already been achieved through chemical sensitive films deposited on the multimode fiber. However, chemical sensing signal interfered by the temperature where the fiber under test locates. In this paper, a new configuration of the fiber sensing is developed using a double cladding fiber. The sensor is feasible for multi-parameter sensing including temperature and another chemical of interest (pH value in this paper) at the same location. In this way, a temperature compensated distributed sensing algorithm can be developed and have both fundamental mode and multimode propagation in the same measure and field. The possibility to adjust the specifications of the fiber and OFDR configuration provides ample opportunity to satisfy requirements of temperature compensation from different chemical sensing applications.

In this paper, a real-time perception system for autonomous car is presented. It is based on a highly parallel architecture using state of the art Field Programmable Gate Array (FPGA) to perform both low and intermediary levels image processing tasks at video frame rate (i.e. 30 frames / s). The hardware algorithm consists to perform noise removal and edge detection, followed by Hough transform task to extract the segments corresponding the lanes boundaries. The rich hardware resources which are available in nowadays FPGAs (e.g. large built-in distributed RAM memories, DSP blocks, and reconfigurable PLLs) yielded for a compact and low power consumption real-time vision system. Series of tests on different roads within Abu Dhabi city were successfully conducted for different scenarios such as continues lines, discontinues lines and slightly curved lines for which the car speed reached up to 122 km/h.