Abstract In laser processing, the possible throughput is directly scaling with the available average laser power. To avoid unwanted thermal damage due to high pulse energy or heat accumulation during MHz-repetition rates, energy distribution over the workpiece is required. Polygon mirror scanners enable high deflection speeds and thus, a proper energy distribution within a short processing time. The requirements of laser micro processing with up to 10 kW average laser powers and high scan speeds up to 1000 m/s result in a 30 mm aperture two-dimensional polygon mirror scanner with a patented low-distortion mirror configuration. In combination with a field programmable gate array-based real-time logic, position-true high-accuracy laser switching is enabled for 2D, 2.5D, or 3D laser processing capable to drill holes in multi-pass ablation or engraving. A special developed real-time shifter module within the high-speed logic allows, in combination with external axis, the material processing on the fly and hence, processing of workpieces much larger than the scan field.

Abstract Smartphone is emerging as a portable analytical biosensing platform in many point-of-care (POC) applications such as disease diagnostics, environmental monitoring, and food toxin screening. With the recent advancement of imaging technologies on the smartphone, the manual control of acquisition settings (e.g., exposure time, frame rate, focusing distance, etc.) has already been expanded from the photo to the video capturing mode. In modern smartphone models, high frame rate (above 100 fps) can be achieved to bring in a new temporal dimension to the smartphone-supported POC tests by recording high-definition videos. This opens up a new analytical method defined as smartphone videoscopy. In this review, the recent development of smartphone videoscopy is summarized based on different POC applications. Representative examples of smartphone videoscopy systems and how these time-dependent measurements could open up new opportunities for POC diagnostics are discussed in detail. The advances demonstrated so far illustrate the promising future of smartphone videoscopy in biosensing, POC diagnostics, and time-resolved analysis in general.

Abstract Two optical sensing elements based on the surface plasmon waves at the plasmonic-photonic-crystal/air interface, excited in the Kretschmann configuration, are proposed. The sensing elements are designed to detect air humidity and NO2 concentration in air. The angular reflectance spectra of the sensing elements are theoretically analyzed as the function of the analyte concentration. The proposed NO2-sensing element has no cross-sensitivity to humidity. The two sensing elements are based on the same multilayer metal-dielectric structure with the only exception on different gas-sensitive material layers. When combined, the sensing elements can be used to measure humidity and NO2 concentration in humid air.

This special issue of Advanced Optical Technologies (AOT) is dedicated to the field of laser-based micro- and nanostructuring methods.

Abstract The invention of new miniaturized and smart medical implants continues in all medical fields, including miniaturized heart pacemakers. These implants often come with a titanium (Ti) casing, which may have to be removed after several months or years and shall therefore not be completely overgrown by cells or scar tissue after implantation. Scar tissue is mainly formed by fibroblast cells and extracellular matrix proteins like collagen produced by them. Suppression of fibroblast growth at Ti surfaces could be achieved by 800 nm femtosecond laser-ablation creating self-organized sharp spikes with dimensions in the 10 μm-range which are superposed by fine sub-μm parallel ripples. On flat Ti control samples, the best results regarding suppression of cell growth were obtained on spike-structures which were additionally electrochemically anodized under acidic conditions. When Ti cylinders with a diameter of 8 mm (similar as the pacemakers) were placed upright in a culture of murine fibroblasts, a multi-layer cell growth up to a height of at least 1.5 mm occurred within 19–22 days. We have demonstrated that a laser-structured and anodized ring around the Ti cylinder surface is an effective way to create a barrier that murine fibroblasts were not able to overgrow within this time.

Abstract Direct femtosecond (fs) laser surface structuring became a versatile way to generate surface structures on solid targets demonstrating a high degree of flexibility and controllability in creating different types of structures for many applications. This approach demonstrated an alteration in various properties of the surface, such as optical properties, wetting response, etc. This paper focuses on direct fs laser surface structuring using complex light beams with spatially variant distribution of the polarization and fluence, with emphasis on the results obtained by the authors by exploiting q-plate beam converters. Although striking scientific findings were achieved so far, direct fs laser processing with complex light fields is still a novel research field, and new exciting findings are likely to appear on its horizon.

This special issue of Advanced Optical Technologies (AOT) is dedicated to the field of laser-based micro- and nanostructuring methods.

Abstract The fabrication of periodic surface patterns on various materials by ultrashort ultraviolet (UV) laser pulses is reviewed. Laser interference ablation using two or more coherent beams leads to deterministic, strictly periodic patterns. The generation of the interfering beams is accomplished by diffractive optical elements like gratings, grating systems or computer-generated holograms. The recombination of the diffracted beams is performed by optical imaging or diffractive beam management. Ultrashort UV pulses are especially suited for generating micron- to submicron-sized deterministic periodic patterns on metals and semiconductors.

the SPIE Photonics West conference and exhibition will open its doors once again at the San Francisco Moscone Center.It is, in fact, not one conference but a congress uniting three main conferences with a large number of side events, and it is not one exhibition but is actually two.About 5200 presentations were given at the last event, 22 000 people attended the conference and there were 1400 exhibitors.The two exhibitions are the BiOS Expo and the Photonics West exhibition.The first is a smaller event with about 220 exhibitors and takes place on the Saturday and Sunday at the beginning of the main conference.The much bigger SPIE Photonics West exhibition starts on Tuesday 4th February 2020 at 10 am and ends on Thursday afternoon at 4 pm.