Angus, a distinguished and eminent scientist, was also a remarkable teacher, mentor, colleague, and friend to the entire thin film optics community.
The 2022 Manufacturing Problem Contest required participants to construct an optical filter with a specified stepped transmittance, showcasing a range from 400 to 1100 nm, encompassing three orders of magnitude. Intra-familial infection Successful completion of the problem depended on contestants' mastery of optical filter design, deposition techniques, and precise measurement methods. Five institutions supplied a group of nine samples, showing total thicknesses between 59 and 535 meters, with a corresponding layer count variance between 68 and 1743. Using entirely independent methods, three laboratories ascertained the spectral properties of the filters. The June 2022 Optical Interference Coatings Conference in Whistler, B.C., Canada, featured the presentation of the results.
Optical absorption, scattering, and mechanical loss in amorphous optical coatings are demonstrably diminished through annealing; elevated annealing temperatures lead to enhanced improvements. Temperature limitations are imposed by the onset of coating degradation, manifested as crystallization, cracking, or bubbling. After annealing, the static appearance of heating-induced coating damage is a common occurrence. To understand the temperature dependence of damage during annealing, a dynamic experimental method is needed. Such a method would provide valuable information to optimize manufacturing and annealing processes, thereby enhancing coating performance. We have developed an instrument, as far as we are aware, incorporating an industrial annealing oven. Side-mounted viewports allow for real-time, in-situ study of optical samples and their coating scatter patterns and damage mechanisms during the annealing process. Observations of in-situ changes to titania-alloyed tantalum coatings on fused silica surfaces are presented in the results. An image (a mapping) of the spatial evolution of these changes is obtained during annealing, which is superior to the use of x-ray diffraction, electron beam, or Raman methods. In light of the existing literature, the cause of these changes is posited to be crystallization. We further investigate the effectiveness of this apparatus in observing additional instances of coating damage, including cracks and blisters.
Conventional coating technologies struggle to effectively apply a layer to complex, 3-dimensional optical structures. TLR2INC29 Large top-open optical glass cubes, characterized by a side length of 100 mm, were functionally adapted in this research to replicate the features of extensive dome-shaped optics. Simultaneously using atomic layer deposition, antireflection coatings were applied to two demonstrators for the visible light range (420-670 nm) and six demonstrators for a single wavelength (550 nm). Reflectance measurements on the internal and external surfaces of the glass cubes confirm an anti-reflective (AR) coating, yielding residual reflectance significantly lower than 0.3% for visible light and 0.2% for individual wavelengths across almost the complete surface area.
Oblique light's interaction with interfaces in optical systems results in polarization splitting, a significant problem. Low-index nanostructured silica layers were generated through the process of overcoating an initial organic template with silica and the subsequent extraction of the organic constituents. Precisely engineered nanostructured layers can be used to produce low effective refractive indices, extending to a minimum value of 105. Homogeneous layers stacked together can produce broadband antireflective coatings with exceptionally low polarization splitting. Thin interlayers between the low-index layers, structured with low indices, yielded improved polarization characteristics.
A broadband infrared absorber optical coating, optimized via pulsed DC sputter deposition of hydrogenated carbon, is presented. Infrared absorptance, exceeding 90% within the 25-20 m infrared band, and diminished reflection, are consequences of using a low-absorptance antireflective hydrogenated carbon overcoat over a broadband-absorbing carbon underlayer, which is nonhydrogenated. The infrared optical absorptance of hydrogen-alloyed sputter-deposited carbon material is decreased. To that end, the optimization of hydrogen flow is elucidated, with the goal of minimizing reflection loss, maximizing broadband absorptance, and establishing a balanced stress. The use of complementary metal-oxide-semiconductor (CMOS) microelectromechanical systems (MEMS) thermopile device wafers is the subject of this exposition. The thermopile output voltage has been shown to increase by 220%, corroborating the anticipated model results.
This research investigates the characterization of the optical and mechanical properties of (T a 2 O 5)1-x (S i O 2)x mixed oxide thin films prepared through microwave plasma assisted co-sputtering, including the influence of post-annealing. Low mechanical loss materials (310-5) with a high refractive index (193) were deposited, all while controlling processing costs. The observed trends included the following: An elevated SiO2 concentration in the mixture correlated with an increase in the energy band gap, and elevated annealing temperatures correlated with a decrease in the disorder constant. Annealing the mixtures resulted in a decrease in mechanical losses and optical absorption. This exemplifies their potential as a low-cost alternative high-index material for optical coatings in gravitational wave detectors.
The findings of the study are both practically significant and intellectually stimulating, concerning the design of dispersive mirrors (DMs) active within the mid-infrared spectral range, spanning from 3 to 18 micrometers. In terms of the key design criteria, mirror bandwidth and group delay variation, the construction of admissible domains was realized. Calculations have yielded estimates for the total coating thickness, the thickest layer's thickness, and the predicted number of layers. Several hundred DM design solutions were analyzed, thereby confirming the results.
Coatings created by physical vapor deposition processes experience changes in their physical and optical properties as a result of post-deposition annealing. Optical coatings' annealing treatments influence the spectral transmission and refractive index. Thickness, density, and stress, among other physical and mechanical properties, are likewise affected by annealing. By investigating the consequences of 150-500°C annealing on N b₂O₅ films produced by thermal evaporation and reactive magnetron sputtering, we explore the basis for these observed changes. Explanations of the data and resolution of conflicts between previous studies are possible through the application of the Lorentz-Lorenz equation and concepts of potential energy.
The 2022 Optical Interference Coating (OIC) Topical Meeting's design challenges encompass reverse-engineering black-box coatings and developing a pair of white-balanced, multi-bandpass filters suitable for three-dimensional cinema projection in both frigid and scorching outdoor settings. Thirty-two design submissions, crafted by 14 designers representing China, France, Germany, Japan, Russia, and the United States, addressed problems A and B. These submitted solutions, along with the problems themselves, have been meticulously described and evaluated.
A characterization method, specifically for post-production, is suggested, based on spectral photometric and ellipsometric data from a prepared sample set. Malaria infection External evaluation of single-layer (SL) and multilayer (ML) subsets, the foundational elements within the final sample, allowed for the precise determination of the final multilayer's (ML) thicknesses and refractive indices. Ex-situ measurement strategies for characterizing the concluding machine learning sample were evaluated, their reliability contrasted, and the most practical characterization technique for scenarios where the preparation of these samples would be prohibitively difficult was recommended.
The nodular imperfection's morphology and the laser's incident angle profoundly affect the spatial distribution of light enhancement within the nodule and the manner in which the laser light is removed from the defect. A parametric study models nodular defect geometries—unique to ion beam sputtering, ion-assisted deposition, and electron-beam deposition—for optical interference mirror coatings constructed with quarter-wave thicknesses and capped with a half-wave layer of a lower-index material. The study encompasses a wide range of nodular inclusion diameters and layer counts. For hafnia (n=19) and silica (n=145) multilayer mirrors, the 24-layer configuration, typical of e-beam deposited coatings across a wide range of deposition angles, was found to maximize light intensification within nodular defects with a C factor of 8. The light intensification within nodular defects was reduced as the layer count for normal-incidence multilayer mirrors was increased, for inclusions of an intermediate size. A second parametric exploration examined the interplay between nodule shape and light intensification, with a set number of layers. The shapes of nodules display a clear and consistent temporal trend in this instance. Narrow nodules, when exposed to normal incidence laser irradiation, exhibit a higher rate of energy drainage from their base compared to wide nodules, which experience greater energy drainage through their upper portion. The nodular defect's laser energy can be evacuated via waveguiding, with a 45-degree incidence angle as the method of implementation. At last, the duration of laser light resonance within nodular imperfections is prolonged compared to the neighboring, non-defective multilayer.
Diffractive optical elements (DOEs) are crucial in modern spectral and imaging systems, but optimizing their diffraction efficiency while ensuring a broad working bandwidth continues to be a difficult problem.