This PDF file contains the front matter associated with SPIE Proceedings Volume 13142, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

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 data storage (ODS) is a promising candidate for massive data storage. It is a sustainable and green technology with the advantages of low energy consumption, high data capacity and long life-time, which once had a high expectation in the data storage market. However, limited storage capacity is one of the main factors which prevents ODS from becoming a favorable competitor against hard disk drive (HDD), flash memory or magnetic tape. Unfortunately, the storage capacity of ODS is constrained by the optical diffraction limit. Although previously reported photoresists allow nanoscale lithography, they can hardly be used in nanoscale optical storage due to a functional deficiency of superresolution readout of the luminescent signal of the written structure. Herein, we endow photopolymerization nanolithography with AIE fluorescence characteristics, which does not destroy the existing nano-writing mechanism2. 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 to increase the recording density of hard disk drives. A near-field transducer (NFT), which forms a small light spot on the recording medium, is necessary in HAMR. We previously proposed a device for a HAMR heat source, in which a metal nano-antenna as an NFT is attached to a semiconductor ring resonator as a light source via a dielectric spacer. We have been analyzing the temperature rise using this device including the recording medium through the combination of optical and thermal simulations. The objective of this study is to decrease the nano-antenna temperature by optimizing its structure. Two types of devices (Types 1 and 2) were newly proposed. In Types 1 and 2, a small hole and a narrow groove, which was filled with a dielectric material, was respectively formed on the side of the ring resonator, and the nano-antenna was partially embedded into it. The metal for the nano-antenna was Au, and the dielectric for the spacer, hole, and groove was SiO₂. When the peak temperature of the recording layer was around 800K (slightly higher than the Curie temperature), the nano-antenna temperature was around 560K for the conventional device, but it could be decreased to around 360 to 380K for the proposed devices. This is a sufficiently low value to keep the hardness of nano-antenna. On the other hand, the thermal spot size in the recording layer for the proposed devices was slightly larger than that for the conventional device.

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, etc. used in classical logic calculations with quantum calculation gates. These classical gates can be expressed as NOT and CNOT of quantum computing gates. We show how to express these quantum gates as optical devices using the behavior of the polarization of discrete photons. Next, we describe the backtracking method of quantum circuits utilizing the reversibility of quantum gates. Since classical gates are not unitary, we use probabilistic methods that rely on measurements. In a typical classical gate, there are multiple inputs corresponding to a certain output, so backtracking requires tracing multiple states. The quantum bit representation, which can represent superposition states, is suitable for this purpose. As an application example, we explain how to backtrack integer multipliers and perform factorization. In configuration using quantum gates, one measurement quantum bit is required for each element, resulting in a large number of state bits. However, by reusing bits that are no longer needed, it was possible to construct a circuit with a number of state bits proportional to the number of bits for the integer multiplicand. We simulated an integer multiplier circuit by combining classical gates, and backtrack the circuit to derive two factors from a composite number represented by quantum bits. We performed simulations on a PC and succeeded in factorizing a 100-bit composite number.

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 viewpoints, 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 measures approximately 360 millimeters in height and achieves a distance measurement error of less than 5% for objects 1.5 meters apart.

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. This contribution to the SPIE Optics & Photonics 2024 conference will report on industrial solutions where sensor technology is ready to take the lead, which is only is possible, when the measurement provides undoubtedly information about the actual process status. Especially for additive manufacturing processes the implementation of OCT technology will introduce a new level of automation.

In this work, a 633nm laser is used. The light beam passes through a fixed linear polarizer before hitting a rectangular container where the solution is located. Different solutions were used, including distilled water, standard sugar, refined sugar and brown sugar. The beam finally travels to a polarizer that can rotate on its own axis and then reaches an optical fiber connector where the signal is processed. The rotating polarizer has a gear configuration and a stepper motor controlled by an ESP32 microprocessor and an external power source, allowing precise control of the polarizer's rotation by the microprocessor. The resulting signal is captured in optical fiber by means of a photodiode and sent to the microprocessor where it is processed and then sent to a mobile device, where it is stored and processed for better understanding. The results of the power obtained when passing a polarized beam through different solutions at different concentrations are analyzed, and a correlation between the amount of sugar contamination and the received power was determinate. The application is based on Angular framework and has a settings tab where the current angle of the polarizer is displayed, buttons to start or stop a measurement, as well as text boxes where parameters for measurements can be configured, such as the direction of rotation and the angular speed of the polarizer. It has various functionalities for graphing the stored data and comparing them, as well as some visualization tools. It also allows viewing a time series with real-time measurements and a section to manage stored data.

This work outlines the analysis and implementation of mechanically induced long-period gratings (MILPGs) in both conventional and non-traditional optical fibers, encompassing standard single-mode fiber (SMF-28), double-cladding fibers such as Thorlabs DCF-13 and Nufern S-1310, and a P-doped fiber. The fabrication of grating involves the application of transverse pressure to specially grooved plates, inducing periodic alterations in fiber structure and refractive index (RI). An innovative aspect in the proposed fabrication process is the use of stereolithography (SLA) 3D printing technique to create interdigitated, nearly sinusoidal-shaped grooved structure. Through this approach, we evaluated the performance of the MILPGs in order to comprehend how weight, grating length and fiber coating influence the effectiveness of MILPG. The characterizations were performed within wavelength range of 1100 to 1700nm. The resulting devices showcase superior spectral characteristics, including negligible power losses and well-defined narrow attenuation bands. Notably, the proposed fabrication method stands out for its cost-effectiveness, it is easy-to-use and capable of rapid production. As a wide range of optical fibers have been explored in this work, each of which possesses unique geometrical and optical characteristics and this comprehensive exploration of fabrication parameters opens avenues for applying these devices in sensing and communication, marking the first comprehensive investigation of MILPGs in these specific optical fibers, thereby making a distinctive and innovative contribution to the field.