Aluminum Mirrors Research Articles

Development of Linear Astigmatism Free—Three Mirror System (LAF-TMS)

We present the development of Linear Astigmatism Free—Three Mirror System (LAF-TMS). This is a prototype of an off-axis telescope that enables very wide field of view (FoV) infrared satellites that can observe Paschen-α emission, zodiacal light, integrated starlight, and other infrared sources. It has the entrance pupil diameter of 150 mm, the focal length of 500 mm, and the FoV of 5.°5 × 4.°1. LAF-TMS is an obscuration-free off-axis system with minimal out-of-field baffling and no optical support structure diffraction. This optical design is analytically optimized to remove linear astigmatism and to reduce high-order aberrations. Sensitivity analysis and Monte-Carlo simulation reveal that tilt errors are the most sensitive alignment parameters that allow ∼1′. Optomechanical structure accurately mounts aluminum mirrors, and withstands satellite-level vibration environments. LAF-TMS shows optical performance with 37 μm FWHM of the point source image satisfying Nyquist sampling requirements for typical 18 μm pixel Infrared array detectors. The surface figure errors of mirrors and scattered light from the tertiary mirror with 4.9 nm surface microroughness may affect the measured point-spread function. Optical tests successfully demonstrate constant optical performance over wide FoV, indicating that LAF-TMS suppresses linear astigmatism and high-order aberrations.

Raman-Enhanced Spectroscopy (RESpect) Probe for Childhood Non-Hodgkin Lymphoma.

Raman-enhanced spectroscopy (RESpect) probe, which enhances Raman spectroscopy technology through a portable fiber-optic device, characterizes tissues and cells by identifying molecular chemical composition showing distinct differences/similarities for potential tumor markers or diagnosis. In a feasibility study with the ultimate objective to translate the technology to the clinic, a panel of pediatric non-Hodgkin lymphoma tissues and non-malignant specimens had RS analyses compared between standard Raman spectroscopy microscope instrument and RESpect probe. Cryopreserved tissues were mounted on front-coated aluminum mirror slides and analyzed by standard Raman spectroscopy and RESpect probe. Principal Component Analysis revealed similarities between non-Hodgkin lymphoma subtypes but not follicular hyperplasia. Standard Raman spectroscopy and RESpect probe fingerprint comparisons demonstrated comparable primary peaks. Raman spectroscopic fingerprints and peaks of pediatric non-Hodgkin lymphoma subtypes and follicular hyperplasia provided novel avenues to pursue diagnostic approaches and identify potential new therapeutic targets. The information could inform new insights into molecular cellular pathogenesis. Translating Raman spectroscopy technology by using the RESpect probe as a potential point-of-care screening instrument has the potential to change the paradigm of screening for cancer as an initial step to determine when a definitive tissue biopsy would be necessary.

Plasma mirror focal spot quality for glass and aluminum mirrors for laser pulses up to 20 ps.

High-intensity short-pulse lasers are being pushed further as applications continue to demand higher laser intensities. Uses such as radiography and laser-driven particle acceleration require these higher intensities to produce the necessary x-ray and particle fluxes. Achieving these intensities, however, is limited by the damage threshold of costly optics and the complexity of target chambers. This is evidenced by the Advanced Radiographic Capability (ARC) short-pulse laser at the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory, producing four high-energy $ \approx 1\;{\rm kJ} $≈1kJ laser pulses at 30 ps pulse duration, being limited to an intensity of $ {10^{18}}\;{\rm W}/{{\rm cm}^2} $1018W/cm2 by the large focal spot size of $ \approx 100\;{\unicode{x00B5}{\rm m}} $≈100µm. Due to the setup complexity of NIF, changing the location of the final focusing parabola in order to improve the focal spot size is not an option. This leads to the possible use of disposable ellipsoidal plasma mirrors (PMs) placed within the chamber, close to the target in an attempt to refocus the four ARC beams. However, the behavior of PMs at these relatively long pulse durations (tens of picoseconds) is not well characterized. The results from the COMET laser at the Jupiter Laser Facility carried out at 0.5 to 20 ps pulse durations on flat mirrors are presented as a necessary first step towards focusing curved mirrors. The findings show defocusing at longer pulse durations and higher intensities, with less degradation when using aluminum coated mirrors.

A robust surface recover algorithm based on random phase noise correction for white light interferometry

White light scanning interferometry is a very important technique for nanometrology. In this paper, a robust white light interference signal processing algorithm using random phase noise correction method is proposed. By analyzing the phase response of the correlgram mathematically, the phase noise is modelized by the combination of random noise and systematic deviation. The random noise can be corrected by assembling the least square result of phase information. As a result, the relationship between phase distribution and surface height is established in a more accurate way. The simulations show that the novel algorithm is capable of achieving robust measurements with standard deviation one tenth comparing to the scanning step length errors, and has an extremely high noise tolerance 14.25 nm with scanning step length 20 nm. In the experiments, a step height standard (VLSI, 182.7 ± 2.0 nm), a protected aluminum mirror and a drive shaft cover of aircraft engine were tested, where the repeatability error for the step height standard is 0.5 nm, the roughness repeatability of the mirror is only 0.03 nm, and the roughness repeatability of the cover is 5.14 nm, which proves the accuracy and robust of the algorithm.

Optical design and fabrication of an all-aluminum unobscured two-mirror freeform imaging telescope

Freeform optics offers more degrees of freedom to optical design that can benefit from a compact package size and a large field of view for imaging systems. Motivated by the advances in modern optical fabrication and metrology, freeform optics has been found in many applications. In this paper, we will describe the challenging optical design, fabrication, metrology, and assembly of an all-aluminum unobscured two-mirror freeform imaging telescope. The telescope has a large field of view of 20∘×15∘. The freeform aluminum mirrors are manufactured by diamond turning based on a feedback modification strategy. The freeform mirrors are measured by a computer-generated hologram-based interferometric null test method. All-aluminum configuration has the advantages of being athermal and cost-effective.

Design and fabrication of additively manufactured aluminum mirrors

To meet the increasing demand for practicality and rapidity of the optical components in aircraft folding optical systems, an aluminum mirror preparation method based on additive manufacturing (AM) technology is proposed. From the perspective of special processing technology for AM, a preparation process chain of additively manufactured mirrors is proposed to address limitations in the design process such as size, support, and connectivity constraints. First, the deposited mirror manufactured by AM technology is prepared. Second, the additively manufactured metal mirror is densified by the hot isostatic pressing process. Then, computer numerical control machining and single-point diamond turning is applied to realize the shape of the surface. Finally, the AM mirror is coated with the gold film. The experimental results show that the surface quality is 0.384λ (peak-to-valley method) and 0.093λ (root mean square method) (λ = 632.8 nm), and the mirror surface roughness (Ra) is better than 8 nm. After the mirror is subjected to thermal cycles, the surface accuracy does not change significantly, which essentially meets the requirements of the aviation environment adaptability and shows good potential for application in the infrared band.

Analisis Penentuan Harga Jual Cermin Alumunium Dengan Menggunakan Metode Cost-Plus Pricing Pada Toko Kaca Mulia Berkah Di Tenggarong

Abstract: The purpose of this thesis research is to find out and examine the selling prices of aluminum mirrors that have been determined by the owner all this time and the calculation of selling prices in accordance with accounting rules by the results of the researchers calculation. The problem in this thesis are that the owner of Mulia Berkah Glass Store has not counting and categorized the cost components that shape the selling prices and have not set or targeted the expected profit from the selling prices that has been valid all this time. The conclusion are the selling prices of aluminum mirrors based on the calculation of researchers using the cost-plus pricing method with full costing approach and the variable costing approach for sizes 35 cm X 91 cm is Rp155.000,-, for sizes 45 cm X 91 cm is Rp172.000,-, for sizes 34 cm X 127 cm is Rp179.000,-, for sizes 35 cm X 127 cm is Rp181.000,-, and for sizes 48 cm X 127 cm is Rp205.000,-. With an expected profit is 1% of total assets with different mark-up percentages for each approach. The selling prices set by the owner has been lower compared to the selling prices calculated by researchers, this is because the owner of Mulia Berkah Glass Store only sets the selling prices based on market prices, where does not accounted and classified the cost components that shape the selling prices with overall and maximum, and have not set or targeted the expected profit from the selling prices. In outline, the selling prices set by the owner at this time is not the selling prices that profitable when compared to the selling prices a result of the researchers calculation. Keywords: Selling price, Cost-plus pricing

Mid-spatial frequency removal on aluminum free-form mirror.

Mid-spatial frequency (MSF) errors challenge freeform manufacture, not in the least due to tool-misfit. This can compromise the performance of functional surfaces and is difficult to remove by post-processing. Our previously reported work on an effective process-chain for aluminum polishing demonstrated the ability to remove MSFs by hard-tool grolishing. In this paper, we describe MSF removal on an aluminum mirror, deformed to a saddle-like freeform shape, using power spectral density (PSD) as a diagnostic. CNC Precessions bonnet polishing was optimized to minimize output MSFs, then a non-Newtonian (n-N) tool was used to attenuate the residual MSFs that were present. Our approach was distinct from the approach pioneered by University of Arizona, in that we adopted small-tool polishing on the saddle-like part, with removal rate restored by rotating the n-N tool. In order to define the optimum window of rotation speeds, the dynamic behavior of the n-N material was explored by modelling and experiments. The tool was deployed on an industrial robot, and we describe a novel 'hyper-crossing' tool-path with wide sweeping paths, which is the logical opposite of the unicursal zero-crossing paths we have previously reported. This new path has proved ideally suited to robots, given their high velocity/acceleration capabilities. Detailed results are presented from the PSD viewpoint.

Finishing of metal optics by ion beam technologies

Ultraprecise mirror devices show considerable potential with view to applications in the visible and the ultraviolet spectral ranges. Aluminum alloys gather good mechanical and excellent optical properties and thus they emerge as important mirror construction materials. However, ultraprecision machining and polishing of optical aluminum surfaces are challenging, which originates from the high chemical reactivity and the heterogeneous matrix structure. Recently, several ion beam-based techniques have been developed to qualify aluminum mirrors for short-wavelength applications. We give an overview of the state-of-the-art ion beam-processing techniques for figure error correction and planarization, either by direct aluminum machining or with the aid of polymer or inorganic, amorphous surface films.

Measuring the detonation reaction zone structure ofJOB-9003 explosive using PDV

In order to obtain the chemical reaction zone of HMX based JOB-9003 explosive, experimental measurements on the detonation wave profile of solid explosives using photon Doppler velocimetry (PDV) have been performed. Planar detonations were produced by impacting the explosive with sapphire flyer launched from a powder gun. Particle velocity wave profiles were measured at the explosive/window interface. LiF windows with very thin vapor deposited aluminum mirrors were used in the experiments. The time resolution of PDV is about 1 ns, and the velocity uncertainty is less than 2%. The measurements show distinct end to the reaction zone indicating a CJ point in JOB-9003. The results show that the reaction time of JOB-9003 is (11±2) ns, and the corresponding reaction length is (0.075±0.014) mm. The CJ pressure is (35.6±0.9) GPa, and the pressure at Von-Neumann spike is (47.9±1.2) GPa.

Customized design and efficient fabrication of two freeform aluminum mirrors by single point diamond turning technique.

The precision single point diamond turning technique has been a promising technology for generating small and medium-sized freeform optical elements with high surface quality. In this paper, we present an extremely off-axis freeform optical system with a large 10.0mm pupil diameter and a low 3.0 F-number over a wide 28° field of view. It is composed of two freeform aluminum mirrors, which are fabricated efficiently by the single point diamond turning machine. The manufacturing strategy and parameters are estimated rationally and comprehensively, based on the freeform surface characters. The freeform aluminum mirror surface can reach submicron surface accuracy and achieve nanometer surface roughness. The final assembled prototype of the off-axis two-mirror freeform display optical system has the advantages of compactness, a broad spectrum, and good display imaging performance.

Wide-field off-axis telescope for the Mesospheric Airglow/Aerosol Tomography Spectroscopy satellite.

We present the development of a compact f/7.3 (D=35 mm) three-mirror reflective telescope for the atmospheric-research microsatellite Mesospheric Airglow/Aerosol Tomography Spectroscopy (MATS). The telescope design was driven by the end users' need for a reflective wide-field (5.67°×0.91°) optic with high stray light rejection and six detection channels with separate image sensors, operating at wavelengths 270-772nm. For the first time, a design method for wide-field off-axis telescopes-in which linear astigmatism is eliminated-was applied and tested in practice. Single-point diamond turning was used to produce two sets of 37-110mm large free-form aluminum mirrors with surface figure errors and roughness values of 34-62nm (RMS)/193-497nm (PV) and 2.8-3.5nm (RMS), respectively. A method that combines precise machining and geometry measurements (using a coordinate measuring machine) was employed to fabricate an aluminum structure to accurately position the mirrors without the need for manual alignment. The telescope was tested with a network of plate beamsplitters and filters, which define the spectral selection for the six detection channels. Imaging performance measurements were carried out using a reflective off-axis collimator, which projects imaging targets at infinite focus. A modulation transfer function (MTF) value of 0.45 at 20lp/mm was measured at ∼760 nm (diffraction limit: 0.85) using a slanted edge target. By modeling the measured mirror surfaces in optical design software, a reoptimization of the mirror positions could be performed and an improved MTF of ∼0.75 at 20lp/mm was predicted. The results demonstrate design- and building methods that can be utilized to make off-axis telescopes for a vast range of applications.

Measuring detonation wave profiles in plastic-bonded explosives using PDV

To obtain reaction zone parameters for several high explosives, experimental measurements of the detonation wave profiles in HMX-, RDX- and PETN-based explosives were performed using photon Doppler velocimetry (PDV). Planar detonations were produced by impacting the explosive with a sapphire flyer in a gas gun. Particle velocity wave profiles were measured at the explosive/window interface. LiF windows with very thin vapor-deposited aluminum mirrors were used for experiments. All measurements show a distinct end to the reaction zone, indicating a Chapman-Jouguet (CJ) point. For HMX-based explosives, the presented measurements show that the fast reaction time is approximately 10±2 ns, whereas for RDX- and PETN-based explosives, the values are 14±3 ns and 7±2 ns, respectively. The reaction times or reaction zone lengths obtained in the present study are smaller than previously reported data but much closer to the estimated values in theory. Additionally, the velocity at the Von Neumann (VN) spike was analyzed using the “beat cycles” method, and the pressure at the VN spike was obtained.

Corrections to “Broadband Near-Infrared Superconducting Nanowire Single-Photon Detector With Efficiency Over 50%” [Jun 17 Art. no. 2200904

We report a broadband superconducting nanowire single-photon detector for the near-infrared waveband. The optical absorptance in this band is enhanced by utilizing a reflective aluminum mirror and a SiO2 layer as an optical cavity. A broadband system detection efficiency (SDE) over 50% from 950 to 1600 nm with a low dark count rate of 10 Hz is realized by coupling a HI 1060 FLEX single-mode fiber. The SDEs reaches 78.3%, 70.9%, and 57.7% at the wavelengths of 1064, 1310, and 1550 nm, respectively. A system timing resolution (jitter) of 83 ps at 1550 nm is obtained. The detector may be useful for broadband applications such as earth observation, environment monitoring, and biomedicine.

Improved ion beam tools for ultraprecision figure correction of curved aluminum mirror surfaces (Erratum)

Improved ion beam tools for ultraprecision figure correction of curved aluminum mirror surfaces (Erratum)

Improved ion beam tools for ultraprecision figure correction of curved aluminum mirror surfaces

Aluminum mirrors offer great potential for satisfying the increasing demand in high-performance optical components for visible and ultraviolet applications. Ion beam figuring is an established finishing technology and in particular a promising technique for direct aluminum figure error correction. For the machining of strongly curved or arbitrarily shaped surfaces as well as the correction of low-to-mid spatial frequency figure errors, the usage of a high-performance ion beam source with low tool width is mandatory. For that reason, two different concepts of ion beam generation with high ion current density and narrow beam width are discussed. (1) A concave ion beam extraction grid system is used for apertureless constriction of ion beams in the low millimeter range. An oxygen ion beam with a full-width at half-maximum (FWHM) of 4.0 mm with an ion current density of 29.8 mA / cm2 was achieved. (2) For even smaller ion beams, a conic aperture design with a submillimeter-sized exit opening was tested. A nitrogen ion beam with an FWHM down to 0.62 mm with an ion current density of 4.6 mA / cm2 was obtained. In situ ion current density mapping is performed by scanning Faraday probe measurements. Special interest is set on the data evaluation for submillimeter ion beam analysis.

Multi-resonant photonic band-gap/saddle coil DNP probehead for static solid state NMR of microliter volume samples.

The most critical condition for performing Dynamic Nuclear Polarization (DNP) NMR experiments is achieving sufficiently high electronic B1e fields over the sample at the matched EPR frequencies, which for modern high-resolution NMR instruments fall into the millimeter wave (mmW) range. Typically, mmWs are generated by powerful gyrotrons and/or extended interaction klystrons (EIKs) sources and then focused onto the sample by dielectric lenses. However, further development of DNP methods including new DNP pulse sequences may require B1e fields higher than one could achieve with the current mmW technology. In order to address the challenge of significantly enhancing the mmW field at the sample, we have constructed and tested one-dimensional photonic band-gap (PBG) mmW resonator that was incorporated inside a double-tuned radiofrequency (rf) NMR saddle coil. The photonic crystal is formed by stacking ceramic discs with alternating high and low dielectric constants and thicknesses of λ/4 or 3λ/4, where λ is the wavelength of the incident mmW field in the corresponding dielectric material. When the mmW frequency is within the band gap of the photonic crystal, a defect created in the middle of the crystal confines the mmW energy, thus forming a resonant structure. An aluminum mirror in the middle of the defect has been used to substitute one-half of the structure with its mirror image in order to reduce the resonator size and simplify its tuning. The latter is achieved by adjusting the width of the defect by moving the aluminum mirror with respect to the dielectric stack using a gear mechanism. The 1D PBG resonator was the key element for constructing a multi-resonant integrated DNP/NMR probehead operating at 190-199 GHz EPR/300 MHz 1H/75.5 MHz 13C NMR frequencies. Initial tests of the multi-resonant DNP/NMR probehead were carried out using a quasioptical mmW bridge and a Bruker Biospin Avance II spectrometer equipped with a standard Bruker 7 T wide-bore 89 mm magnet parked at 300.13 MHz 1H NMR frequency. The mmW bridge built with all solid-state active components allows for the frequency tuning between ca. 190 and ca. 199 GHz with the output power up to 27 dBm (0.5 W) at 192 GHz and up to 23 dBm (0.2 W) at 197.5 GHz. Room temperature DNP experiments with a synthetic single crystal high-pressure high-temperature (HPHT) diamond (0.3 × 0.3 × 3.0 mm3) demonstrated dramatic 1500-fold enhancement of 13C natural abundance NMR signal at full incident mmW power. Significant 13C DNP enhancement (of about 90) have been obtained at incident mmW powers of as low as <100 μW. Further tests of the resonator performance have been carried out with a thin (ca. 100 μm thickness) composite polystyrene-microdiamond film by controlling the average mmW power at the optimal DNP conditions via a gated mode of operation. From these experiments, the PBG resonator with loaded Q ≃ 250 and finesse F≈75 provides up to 12-fold or 11 db gain in the average mmW power vs. the non-resonant probehead configuration employing only a reflective mirror.

Improving the performance of single point diamond turning surface with ion beam figuring

Single point diamond turning (SPDT) can directly produce high precision optical parts, but some regularity micro structure in residual surface, and turning processing characteristics limit the surface quality to further improve. Ion beam figuring (IBF), as the last process of optical processing, can remove certain mid and high frequency errors, improve the surface performances without destroying their forms. Therefore, it is proposed to combine SPDT and IBF to manufacturing ultra-high precision surface. Two samples of diamond-turned sphere aluminum mirror were used in this experiment. One samples with surface PV and RMS 226 nm and 12.6 nm decreased to 113 nm and 7.7 nm after ion beam figuring, another sample was improved in the same degree, and the turning marks is removed with surface roughness decreased to 2.8 nm from 3 nm. The experimental results indicate that IBF can remove the turning marks and improve the surface precision in a certain range without destroying the surface form.

Variable Thickness Porous Anodic Alumina/Metal Film Bilayers for Optimization of Plasmonic Scattering by Nanoholes on Mirror.

Continuously variable thickness porous anodic aluminum oxide (PAAO) films were obtained using electrochemical oxidation of bulk aluminum sheet while both electrodes were simultaneously withdrawn from the electrolyte solution. The thickness gradient was controlled by the withdrawal rate (1–10 mm/min range) and thickness variation demonstrated from below 50 nm to above 1 micrometer. The thickness increased linearly with the sample lateral coordinate, whereas the nanopore structure (diameter and interpore distance) remained unchanged. Effects of the initial pore growth and capillary forces are discussed. The presented method can be used for tuning optimal PAAO thickness for optical and other applications as exemplified by finding maximum plasmonic scattering in structured Al–PAAO–Au multilayers. Enhanced scattering from porous gold film separated by a specific-thickness PAAO layer from aluminum mirror surface is demonstrated.

Atomic Layer Deposition of Lithium Fluoride Optical Coatings for the Ultraviolet

Lithium fluoride is an important material for ultraviolet optical systems, possessing among the largest optical bandgaps of dielectric materials. We report on the development of an atomic layer deposition (ALD) process for lithium fluoride that is capable of depositing thin films in a self-limiting manner, with an approximate deposition rate of approximately 0.15 Å per ALD cycle at a substrate temperature of 150 °C. Films are characterized by spectroscopic ellipsometry, atomic force microscopy, X-ray photoelectron spectroscopy, and far ultraviolet reflectometry. For substrate temperatures of 150 °C and greater, films showed significant microroughness with a correlated reduction in effective refractive index. This behavior was mitigated by a reduction in substrate temperature to as low as 100 °C. Films deposited on silicon substrates were subjected to long-term storage testing to evaluate the environmental sensitivity of the deposited layers. Protected aluminum mirrors were also fabricated with ALD LiF overcoats, yielding a reflectance of 84% at a wavelength of 125 nm. The performance relative to state-of-the-art LiF thin films deposited by physical vapor deposition methods is discussed, along with the prospects for future optimization.