Multilayer Optics Research Articles

Circularly polarized colour reflection from helicoidal structures in the beetle Plusiotis boucardi

A detailed optical study of the iridescent outer-shell of the beetle Plusiotis boucardi has revealed a novel microstructure which controls both the polarization and wavelength of reflected light. A previously unreported hexagonal array across the integument of the beetle exhibits highly localized regions of reflection of only red and green left-handed circularly-polarized light. Optical and transmission electron microscopy (TEM) imaging reveals the origin of this effect as an array of ‘bowl-shaped’ recesses on the elytra that are formed from a dual-pitch helicoidal layer. Reflectivity spectra collected from the beetle are compared to theoretical data produced using a multi-layer optics model for modelling chiral, optically anisotropic media such as cholesteric liquid crystals. Excellent agreement is obtained between data and theory produced using a model that incorporates an upper isotropic layer (of cuticular wax), followed by a short pitch (310 (± 1) nm) overlying a longer pitch (370 (±1) nm) helicoidal layer of optically anisotropic material. These layers are backed by an absorbing underlayer. Synthetic replication of this form of structure may provide a route to the fabrication of tuneable micro-mirrors for optical applications.

Laser Ablation as Enabling Technology for the Structuring of Optical Multilayer Structures

In this paper, laser ablation is presented as a versatile technology that can be used for the fabrication of all building blocks and functional elements required for an optical interconnection, integrated in printed circuit boards (PCBs). The integration of optical interconnections in PCBs is an emerging field in which interest worldwide is rapidly growing. The limiting factor is mainly the compatibility of new technologies, used to define and fabricate the optical interconnections, with standard FR4-processing steps, temperatures and lamination pressures. Laser ablation, which is currently frequently used for the drilling of electrical micro-vias in PCBs, has proven to be fully compatible with standard PCB manufacturing. An optical two layer structure is studied that can make full use of the functionalities of 2D elements such as VCSEL or photodiode arrays.

Study of Signal Processing for Optical Multi-Layer Disk

Research intended to increase the capacity of multi-layer optical disks has frequently applied to multi-layer disks the format for a single layer disk. However, when writing and reading data through non-readout layers, light intensity is fluctuated by data recorded on those layers. To solve this problem, we invented a modulation code, and studied a way to detect data from recorded marks. We report the results of this research here

The role of mediation in collisions and related analogs

We analyze the problem of one-dimensional collisions between a target mass m and the incident mass M and a third object, the mediator. The concept of an optimal mediator that yields the most efficient energy transfer between the incident and target objects is introduced. A mediator consisting of a chain of colliding particles with masses that follow a geometric progression is considered. A paradox that arises when the number of particles in the chain goes to infinity is discussed. In this case a complete energy transfer from the incident to the target mass can be achieved for any mass ratio M∕m. The analogs of this problem in multilayer optics and quantum mechanics are also discussed.

Determination of Thermal Conductivity of Amorphous Silicon Thin Films via Non-Contacting Optical Probing

The thermal conductivity of amorphous silicon (a-Si) thin films is determined by using the non-intrusive, in-situ optical transmission measurement. The thermal conductivity of a-Si is a key parameter in understanding the mechanism of the recrystallization of polysilicon (p-Si) during the laser annealing process to fabricate the thin film transistors with uniform characteristics which are used as switches in the active matrix liquid crystal displays. Since it is well known that the physical properties are dependent on the process parameters of the thin film deposition process, the thermal conductivity should be measured. The temperature dependence of the film complex refractive index is determined by spectroscopic ellipsometry. A nanosecond KrF excimer laser at the wavelength of 248 nm is used to raise the temperature of the thin films without melting of the thin film. In-situ transmission signal is obtained during the heating process. The acquired transmission signal is fitted with predictions obtained by coupling conductive heat transfer with multi-layer thin film optics in the optical transmission measurement.

In-situ ellipsometric monitor with layer-by-layer analysis for precise thickness control of EUV multilayer optics

Ion beam sputtering fabrications of Mo/Si multilayers for soft X-ray mirrors were studied using an automatic null ellipsometer. The ellipsometric growth curves plotted on the complex plane showed island structure formation for every Mo layer grown on Si when deposition was performed with a 1400 V Ar ion beam. The ellipsometric growth curves indicated that the multilayers fabricated with 900 V ions had sharper and smoother interfaces compared to those fabricated with 1400 V ions. Quantitative layer-by-layer analysis showed that the Si layers deposited at 1400 V became optically isotropic as thin as 1 nm. These data depict the usefulness of our in-situ ellipsometer in controlling layer thickness and also optimizing the deposition condition to form homogeneous and optically isotropic layer structures.

Multilayer optics for high brightness X-ray sources

Multilayer optics for high brightness X-ray sources

Kirkpatrick-Baez mirrors used in high resolution X-ray microscopy, tomography and fluorescence analysis

The combination of a very brilliant X-ray source and state-ofthe-art X-ray optics opens the way to nano-focusing applications. Dynamically bent graded multilayers set in the KB-geometry are developed at the ESRF as an extremely efficient device to focus undulator radiation to spots below 100 nm [1]. The smallest 2D focus reached so far with this device is of the order of 80 nm in both directions. This has been achieved both on a long, coherent beamline and on a shorter beamline using the concept of a secondary source. The first mirror of the system, coated with a graded multilayer, plays both the role of vertical focusing device and monochromator, resulting in a very high flux (a few 10 11 photons/s) and medium monochromaticity (ΔE/E∼10p). Two different fields benefit particularly from the combination small focus / high flux: projection microscopy (magnified tomography) and X-ray fluorescence mapping. In projection microscopy the sample is set at a small distance (10-100 mm) downstream or upstream of the focus and a magnified Fresnel diffraction pattern is recorded on a medium resolution detector set at a large distance (several meters) from the focus. This approach allows to overcome the spatial resolution limit imposed by the detector in the parallel beam geometry. It was used to give direct evidence of nanometric invasion-like grain boundary penetration in the Al/Ga system [2]. For tomography, scans are acquired at different focussample distances. This yields variable magnifications, but also different effective propagation distances (∼equal to the focussample distance). The principal difficulties in this approach are related to the mirror imperfections and the pronounced refraction effects at the sample edges when going to sub-100 nm pixel sizes. Satisfactory results were however obtained in local tomography mode on aluminium alloys. A correction for mirror figure error and a phase retrieval method adapted to the imaging setup are incorporated in the tomograhic procedure [3]. In fluorescence imaging the sample is scanned through the focal plane while the spectrum of the emitted fluorescence is recorded with an energy dispersive detector. This rich probe, complementary to transmission imaging, provides element specific information and allows to image and quantify trace elements. The possibility to apply this method to the field of neurochemistry at the sub-cellular level has been demonstrated. Finally, the best one dimensional focus reached so far with reflective multilayer optics is 40 nm. The ultimate limits of this focusing approach will be discussed.

X-ray diffraction and Raman spectroscopy studies of high-pressure polymorphs ofL- andDL-serine

In the last 20 years, multilayer optics for x-ray and EUV applications have revolutionized the measurement capabilities and the experimental set ups of synchrotron beamlines. Rigaku Innovative Technologies (formerly Osmic) has pioneered these technologies by designing, engineering and manufacturing of distinctive multilayer coatings. We are experienced and internationally recognized for our innovative technologies.We control our production of specified internal roughness on the atomic level while creating layered materials of defined thickness. These multilayers have d-spacings, synonymous for layer-pair thickness, which we can produce uniform, laterally graded, depth graded or even a combination of both gradients. We guarantee our specifications and we have a wide range of metrology technology in house, enabling us to keep our promised specifications and to expand the technical boundaries in our field of applications. Our core capabilities are the detailed knowledge of distinctive multilayer coating technology including the mounting and alignment of optics. We do direct coating on prefigured substrates or, mostly for applications in analytical laboratories, bonding of thin substrates to flat or curved backings. Having delivered thousands of multilayer structures to the analytical scientific market, we are able to design and engineer multilayers on the basis of numerical and analytical simulations of thickness, roughness, required densities and other optical parameters. This technology gives us the possibility to produce just as one example multilayers with a period of 15 Angstroms, a reflectivity of much better than 30% and an energy resolution of better than 0.4%. We also have coatings and multilayer structures for substrates up to 1400 mm length and 400 mm width. The number of chemically different coatings we are able to perform is very broad. This is starting with the classical W/Si through Mo/B4C to a lot of other material combinations. We also design and produce dual wavelength multilayers, narrowand broad-bandwidth multilayers for energy ranges from 40ev to 40 keV. Please see figure (1) for further details. Here we have shown our calculated values for two different multilayer sandwiches. Further material will be shown. Our actual production quality will also be presented.

Structure of the Mouse Peptide N-Glycanase-HR23 Complex Suggests Co-evolution of the Endoplasmic Reticulum-associated Degradation and DNA Repair Pathways

Peptide N-glycanase removes N-linked oligosaccharides from misfolded glycoproteins as part of the endoplasmic reticulum-associated degradation pathway. This process involves the formation of a tight complex of peptide N-glycanase with Rad23 in yeast and the orthologous HR23 proteins in mammals. In addition to its function in endoplasmic reticulum-associated degradation, HR23 is also involved in DNA repair, where it plays an important role in damage recognition in complex with the xeroderma pigmentosum group C protein. To characterize the dual role of HR23, we have determined the high resolution crystal structure of the mouse peptide N-glycanase catalytic core in complex with the xeroderma pigmentosum group C binding domain from HR23B. Peptide N-glycanase features a large cleft between its catalytic cysteine protease core and zinc binding domain. Opposite the zinc binding domain is the HR23B-interacting region, and surprisingly, the complex interface is fundamentally different from the orthologous yeast peptide N-glycanase-Rad23 complex. Different regions on both proteins are involved in complex formation, revealing an amazing degree of divergence in the interaction between two highly homologous proteins. Furthermore, the mouse peptide N-glycanase-HR23B complex mimics the interaction between xeroderma pigmentosum group C and HR23B, thereby providing a first structural model of how the two proteins interact within the nucleotide excision repair cascade in higher eukaryotes. The different interaction interfaces of the xeroderma pigmentosum group C binding domains in yeast and mammals suggest a co-evolution of the endoplasmic reticulum-associated degradation and DNA repair pathways.

Dielectric SiO2∕ZrO2 distributed Bragg reflectors for ZnO microcavities prepared by the reactive helicon-wave-excited-plasma sputtering method

Reactive helicon-wave-excited-plasma sputtering method is shown to be a suitable technique for the fabrication of high reflectivity (R) distributed Bragg reflectors (DBRs), in particular, operating at the resonance wavelength of B excitons in ZnO (366.5nm), utilizing quarter-wavelength multilayers of SiO2 and ZrO2 dielectric films. According to the surface-damage-free nature and proper stoichiometry controllability of the method, dense dielectric films exhibiting ideal refractive indices (1.46 for SiO2 and 2.10 for ZrO2 at 633nm) and small root-mean-square values for the surface roughness (0.20nm for SiO2 and 0.53nm for ZrO2) were deposited using Si and Zr targets and O2 gas at room temperature. Optical reflectance spectra of the SiO2∕ZrO2 DBRs agreed with those calculated using the optical multilayer film theory, and eight-pair DBR exhibited R higher than 99.5% at 366.5nm and 82nm stop bandwidth (R⩾95%). The results indicate that the DBR can be used for the realization of polariton lasers using ZnO microcavities.

Materials for Optical Data Storage

AbstractThe development of recording materials has been a critical component in the advancement of optical data storage. The continual need for improved performance in both consumer and business applications has pushed forward the capabilities of optical storage. In this issue of MRS Bulletin, we review some of the important developments in the materials behind established technologies such as compact discs, digital versatile discs, and magneto-optical recording; the emerging technology of blue recording; and two technologies that seek to extend the performance roadmap for optical storage, multilayer and holographic recording.

Multilayer X-ray optics at CHESS

Almost half of the X-ray beamlines at the Cornell High Energy Synchrotron Source (CHESS) are based on multilayer optics. ;Traditional' multilayers with an energy resolution of DeltaE/E approximately 2% are routinely used to deliver X-ray flux enhanced by a factor of 10(2) in comparison with standard Si(111) optics. Sagittal-focusing multilayers with fixed radius provide an additional factor of 10 gain in flux density. High-resolution multilayer optics with DeltaE/E approximately 0.2% are now routinely used by MacCHESS crystallographers. New wide-bandpass multilayers with DeltaE/E = 5% and 10% have been designed and tested for potential applications in macromolecular crystallography. Small d-spacing multilayers with d < or = 20 A have been successfully used to extend the energy range of multilayer optics. Analysis of the main characteristics of the Mo/B4C and W/B4C small d-spacing multilayer optics shows enhancement in their performance at higher energies. Chemical vapour deposited SiC, with a bulk thermal conductivity of a factor of two higher than that of silicon, has been successfully introduced as a substrate material for multilayer optics. Characteristics of different types of multilayer optics at CHESS beamlines and their applications in a variety of scattering, diffraction and imaging techniques are discussed.

Interface-engineered EUV multilayer mirrors

Most applications of Mo/Si multilayer optics in EUV lithographic systems require a high normal-incidence reflectivity. Using dc-magnetron sputtering we achieved R = 68.8% at the wavelength of 13.5 nm. Different interface-engineered Mo/X/Si/X multilayers with a maximum reflectivity of 69.6% were developed. These new multilayer mirrors consist of molybdenum and silicon layers separated by different interdiffusion barriers (X = C and SiC). The Mo/C/Si/C interface-engineered mirrors were optimized in terms of high peak reflectivity at a wavelength near 13.5 nm ( R p ⩾ 60.0%) and broad operating temperature range ( T = 20–500 °C). The best results were obtained with 0.8 nm thicknesses of carbon interlayers on both interfaces. The combination of good optical properties and high thermal stability of interface-engineered Mo/C/Si/C multilayer mirrors underlines their potential for their use in EUV optics.

EUV multilayer optics

According to the optics requirements of an EUVL tool, the accurate deposition of high reflective and laterally graded multilayers on ultraprecise polished substrates can be regarded as one of the major challenges of EUV lithography development today. To meet these requirements, a new dc magnetron sputtering system NESSY and technologies to coat laterally graded EUV multilayers on curved optics were developed. The major characteristics of the deposition tool and results of sputtered multilayer optics are presented in this paper.

Characterization of a CZT focal plane small prototype for hard X-ray telescope

The promise of good energy and spatial resolution coupled with high efficiency and room temperature operation has fuelled a large international effort to develop cadmium zinc telluride (CZT) for hard X-ray applications. We are involved on the development of a hard X-ray telescope based on multilayer optics and focal plane detector operative in the 10-80 keV energy range. This telescope requires a high efficiency focal plane providing both fine spatial resolution and spectroscopy with a compact and robust design. This paper reports preliminary results on the characterization both in spectroscopic and spatial response of two small pixellated CZT detectors (10times10times1 mm3 and 10times10times2 mm3 single crystals) with 0.45 mm pixel size. We present the results obtained using both standard commercial read-out electronics Readout Electronics for Nuclear Applications (RENA) and innovative low noise and low power dissipation ASICs developed within the collaboration

State‐of‐the‐art of Multilayer Optics for Laboratory X‐ray Devices

AbstractMultilayer X‐ray optics with single layers of a few nanometers thickness can be obtained nowadays. These optics are used in X‐ray diffractometers (XRD), X‐ray fluorescence spectrometers (XRF) and at synchrotron sources. A detailed description of the production of multilayer X‐ray optics using sputter deposition methods is presented and the simulation of X‐ray optics and characterization with X‐ray analytical measurements are explained. Finally, the advantages of multilayer X‐ray optics in typical X‐ray analytical applications are summarized.

Multilayer optics for Mo radiation based X-ray crystallography

Multilayer optics for Mo radiation based X-ray crystallography

Crystallographic data collection using a 0.22% bandwidth multilayer

To bridge the gap between traditional multilayer and crystal optics a high-resolution multilayer monochromator with a bandwidth of 0.22% has been designed and installed on a bending-magnet beamline (F3) at the Cornell High Energy Synchrotron Source (CHESS) to provide an unfocused monochromatic X-ray beam for protein crystallography experiments. Crystallographic data of excellent quality from a medium-sized protein, Concanavalin A, were collected and processed using standard crystallographic programs. The data were successfully used for a structure solution and refinement. The flux from the multilayer monochromator is enhanced, relative to that from a flat Si(111) monochromator, by a factor of 5; consequently, data collection is faster and/or smaller samples may be used. At the same time, the bandwidth is narrow enough to avoid streaked spots. This experiment suggests that multilayer optics may play a valuable role in satisfying the demands of the structural biology community for rapid X-ray data collection, particularly at under-utilized bending-magnet beamlines.

Thin film filters for an EUV multilayer mirror optics with a laser produced plasma light source

For rejection of unwanted background component in the reflection spectrum of EUV multilayer mirrors, thin film transmission filters of Mo, Zr, and Be were evaluated with a laser produced plasma EUV source and an imaging plate detector. It is found that in addition to a standard Zr filter, a Mo filter has good rejection characteristics. In particular, for multilayer mirror use at a large angle of incidence such as the polarizing angles around 45°, Mo shows better rejection characteristics than Zr. It is also confirmed that Be transmits non-ignorable amount of UV background.