1,720,993 research outputs found
Optical society of America's 2013 topical meeting on optical interference coatings: Introduction by the feature editors
No full textThis Applied Optics feature issue is dedicated to the 12th topical meeting on Optical Interference Coatings held on 16-21 June 2013 in Whistler, British Columbia, Canada. The conference, taking place in a three-year rotation with conferences in Europe and Asia, is a focal point for global technical interchange in the field of optical interference coatings and provides premier opportunities for people in the field to present their new advances in research and development. Papers presented at the conference cover a broad range of topics, from thin film deposition processes, designs and modeling, materials, and metrologies to a wide array of thin film applications
Variable optical filters for earth-observation imaging minispectrometers
No full textSmall-dimension, low-mass spectrometers are useful for both Earth observation and planetary missions. A very compact multi-spectral mini-spectrometer that contains no moving parts, can be constructed combining a graded-thickness filter, having a spatially variable narrow-band transmission, to a CCD array detector. The peak wavelength of the transmission filter is moving along one direction of the filter surface, such that each line of a two-dimensional array detector, equipped with this filter, will detect radiation in a different pass band. The spectrum of interest for image spectrometry of the Earth surface is very wide, 400-1000nm. This requirement along with the need of a very small dimension, makes this filter very difficult to manufacture. Preliminary results on metal-dielectric wedge filters, with a gradient of the transmission peak wavelength equal to 60nm/mm, are reported. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only
Effects of proton irradiation on thin-film materials for optical filters
No full textThe behaviour of interference optical filters for space applications has been investigated under low energy proton irradiation. In order to understand the behaviour of the interference coating subjected to proton irradiation, the interaction of protons with coating and substrate was simulated by the SRIM code. A beam of protons of 60 KeV with an integrated fluence of 1013 p+/cm2 was used. The spectral transmittances of fused silica, TiO2 and HfO2 single layers and interference coatings were measured before and after irradiation and, according to simulations, no significant effects were detected in the visible-near infrared spectrum, while some variations appeared at shorter wavelengths. © 2012 ESA and CNES
Optical and electrical characteristics of transparent and highly conductive ultrathin nickel films
No full textSmooth ultrathin transparent conductive Ni films were fabricated by radio frequency sputtering at room temperature. A novel method based on angle resolved transmittance and reflectance measurements allowed calculation of films optical constants. © OSA 2016
Hyperspectral MWIR camera for environmental gas monitoring
No full textA design study is reported for light and compact hyperspectral camera operating in the MWIR and having a linear variable filter as a core dispersive element, for applications in remote monitoring of environmental gases. © 2016 OSA
Ultra compact spectrometer using linear variable filters
No full textThe Linearly Variable Filters (LVF) are complex optical devices that, integrated in a CCD, can realize a «single chip spectrometer». In the framework of an ESA Study, a team of industries and institutes led by SELEX-Galileo explored the design principles and manufacturing techniques, realizing and characterizing LVF samples based both on All-Dielectric (AD) and Metal-Dielectric (MD) Coating Structures in the VNIR and SWIR spectral ranges. In particular the achieved performances on spectral gradient, transmission bandwidth and Spectral Attenuation (SA) are presented and critically discussed. Potential improvements will be highlighted. In addition the results of a feasibility study of a SWIR Linear Variable Filter are presented with the comparison of design prediction and measured performances. Finally criticalities related to the filter-CCD packaging are discussed. The main achievements reached during these activities have been: - to evaluate by design, manufacturing and test of LVF samples the achievable performances compared with target requirements; - to evaluate the reliability of the projects by analyzing their repeatability; - to define suitable measurement methodologies. © Copyright SPIE
Effects of ultraviolet solar photons on thin-film optical filters for space applications
No full textUltraviolet solar photons could induce some variation in the performance of optical coatings exposed to solar irradiation. Consequently optical components and instruments containing such coatings can suffer performance degradation in the space environment. The effects of ultraviolet solar photons on the transmittance of single layer coatings and optical filters, has been investigated. The beamline of a synchrotron light source was used for the irradiation test, being the irradiance in the ultraviolet region comparable to the solar spectrum. Some changes induced by such irradiation are detected in silicon dioxide, which shows an increased absorption below 350 nm. On the contrary, hafnium oxide characteristics seem unaffected. Narrow-band filters containing both these materials show a reduction of transmission in the passband
Phase distortion and thickness variation in the design of optical coatings
No full textOptical coatings are widely used in space instrumentation for obtaining antireflection and high-reflection components or for filtering the incoming radiation. © 2017 SPIE
Transparent and conductive Al-doped ZnO films for solar cells applications
No full textGeneral rules governing the quality of aluminium-doped zinc oxide films (Al:ZnO, AZO) grown by radio frequency sputtering were searched. A vast set of experimental data on the electrical, optical, structural, and morphological properties of AZO films prepared at different deposition conditions was analyzed. AZO films with a high Haacke's figure of merit ΦTC = 10 m Ω-1 were fabricated at temperatures lower than 250 °C starting from a target of ZnO mixed with 2 wt% Al2O3. It was demonstrated that AZO films with similar good optical and electrical properties can be obtained in different ways by opportunely combining the deposition parameters, proving that AZO film characteristics depend on the energy efficiency of the deposition process, which can be ensured at different deposition conditions. It was found that the temperature and the magnetron strength are essential for the growing process to guarantee film optimal performances, while the other deposition parameters can be opportunely adjusted for tuning the film characteristics. A correlation between electrical, structural and microstructural characteristics of the films was established. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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