bluuebunny/crossref_metadata_2025 huggingface dataset:
Atomic Deuterium Adsorption on ultrathin Ge film deposited over Si(100)–2×1
Authors: Gheyas Syed Irfan , Urisu Tsuneo , Hirano Shinya , Nishio Mitsuhiro , Ogawa Hiroshi
Published: February 2023

Deuterium and hydrogen adsorption, especially hydrogen adsorption, on Si(100) and also on Ge(100) have been studied quite extensively in the recent past. These studies reveal some fundamental differences between the way hydrogen reacts with these two surfaces. Different hydride phases have been found to form on Si(100) by hydrogen adsorption at different temperatures, i.e., chemisorption at 630 K yields only monohydride phase (2×1 phase), at 400±10 K, formation of both the monohydride and dihydride phases (3×1 phase) occur and at <400 K, the surface is a mixture of monohydride, dihydride and trihydride species (1×1 phase).1 Since (1×1) phase involves trihydrides ie. SiH3(a), which requires Si–Si bond breaking, substantial surface reconstruction and disordering become inevitable. Heating this phase results in SiH4 desorption along with H2, whereas almost only H2 desorbs from both the (2×1) and (3×1) phases when heated. Hydrogen chemisorption on the Ge(100) surface, on the other hand, has widely been reported to yield only monohydrides (2x1 phase).2,3 Also only hydrogen has been found to desorb from the hydrogen–covered–Ge surface during temperature programmed desorption measurements. It, however, would be interesting to study the effect of hydrogen or deuterium on ultrathin Ge deposited over Si(100), a system of intense cunent research, where strains resulting from lattice mismatch between Si and Ge can open up new possibilities.
Nonlinear Optical Effects in Fractal Nanostructured Materials Such as Nanocomposites and Self-Affine Surfaces
Authors: Poliakov Evgeni , Shalaev Vladimir M. , Markel Vadim , Botet Robert
Published: February 2023

A number of optical phenomena experiences a giant enhancement in metal nanocomposites and rough thin films consisting of small nm-sized particles and roughness features, respectively. The major contribution to this enhancement originates from the large local electromagnetic fields caused by the resonant optical excitation of surface plasmons.
Metal Island Films for Write-Once Optical Data Storage Media
Authors: Baba Kazutaka , Yamaki Kizuku , Miyagi Mitsunobu
Published: February 2023

Write-once (WO) optical disks with high reflectance are becoming attractive data storage media for small production runs of specific compact discs (CD) or Digital Video Discs (DVD). A metal island film is one of the interesting media proposed for such WO optical disk media [1-3]. The metal island film is composed of metal nanoclusters (i.e., islands) and exhibits resonance-type absorption in a visible - near infrared region. Near the resonance peak wavelength, it has not only large absorptance but also high reflectance due to the resonance of free electrons in the metal islands. As the optical characteristics of the metal island film are greatly changed by heating the film, it can be used as heat-mode WO media. The metal island films have some advantages over other WO media, i.e. (1) high reflectance, (2) large absorbance, and (3) low stress in the films from those discontinuous island structure. In addition, the very short recording time is expected since the optical characteristics of the metal island films can be greatly changed by the slight changes of the nanometer-size metal islands [1,3]. We have investigated gold (Au), silver (Ag), copper (Cu), and aluminum (Al) island films for the WO optical data storage media. In this paper, we show the optical changes of those island films at the commercially useful wavelength of 800 nm and demonstrate the highly reflective WO media with the reflectance of 70 % using the Ag island films. It seems that those island films are useful as CD-DVD compatible WO optical data storage media.
Synthesis, Dispersion and Optical Properties of Nanostructured FCC Gallium Nitride
Authors: Gonsalves K.E. , Carlson G. , Rangarajan S.P. , Benaissa M. , José-Yacamán M.
Published: February 2023

Binary III-V materials have recently attracted significant interest[1]. This is due to their high bandgap energy (3.1 - 3.8 eV) which makes them suitable for creating and processing blue light. Eventually, devices based on these materials will bring advances in the fields of communications and computing. However, most of the research on III-Vs has concentrated on vapor-deposited solid films. Interest has also been focused [2] on materials with large third-order nonlinear optical susceptibility.
Evolution of Si Nanocrystals Towards Quantum Confinement
Authors: Delgado Gildardo R. , Lee Howard W. H.
Published: February 2023

Optical studies of nanocrystalline silicon were performed, which include: photoluminescence, excitation, and absorption spectroscopy. The results presented here differ from those observed in porous silicon and in other nanocrystalline silicon systems in various subtle ways. We report on the evolution of Si nanocrystals as they evolve into the size regime where quantum confinement effects are observed Size-selective spectroscopy on a distribution of different-sized Si nanocrystals in a methanol colloid exhibit uniform spectral shifts with excitation wavelength. Quantum confinement effects are clearly identified.
Superzone diffractive lenses
Authors: Futhey John , Fleming Madeleine
Published: February 2023

Diffractive optical elements, particularly kinoforms, can be fabricated by multi-mask photo-lithography or by diamond turning. At the 3M Optics Technology Center in Petaluma California, we are currently investigating methods to diamond turn such optics. As the aperture of the optic increases and the f/number decreases, the number of discrete zones that must be cut increases and the size of the individual zones becomes smaller. This combination of more and smaller zones provides a challenge -- and an eventual limit -- to diamond turning capabilities. We show how a novel design allows us to diamond turn diffractive optics that are larger and faster than was previously possible, but whose theoretical performance is nearly diffraction limited.
System Design for Planar Optics
Authors: Jahns Jürgen
Published: February 2023

Planar optics was proposed as a way to build miniaturized free-space optical systems by using planar fabrication techniques that are used the production of integrated circuits and with minimal need for mechanical assembly and alignment [1-3]. Furthermore, the use of computer aided design tools and foundry-based manufacturing is supposed to further adapt the procedures of the electronics industry to optics [4-6].
Fabrication and Integration of DOEs into High Density Vertical Interconnects
Authors: Haas Franz , Honey David A , Bare Harold , Mikolas David , Craighead Harold , Bojko Richard , Pugh Graham
Published: February 2023

Diffractive optical element (DOE) designs and fabrication techniques were investigated for a vertical optical interconnect architecture illustrated in Fig 1. This design provides high interconnect densities for stacked Multi Chip Module (MCM) computer architectures required in future high speed, low power, and small size computer systems. A 16 channel interconnect was demonstrated and an evaluation of greater interconnect densities is presented. Key design parameters for this effort were: ease of fabrication, compatibility of fabrication techniques with industry standards, density of interconnects, misalignment tolerance, data rates, and power consumption.
Artificial distributed index structures realized by zero order gratings
Authors: Haidner H. , Kipfer P. , Sheridan J.T. , Stork W. , Streibl N.
Published: February 2023

The effective refractive index of a high frequency grating can be altered by changing its duty cycle. First experiments for infrared optical distributed index components are presented.
Design of 1-D Anti-Reflection Structured Surfaces Using Second-Order Effective Medium Theory
Authors: Raguin Daniel H. , Morris G. Michael
Published: February 2023

Recently, the use of anti-reflection structured (ARS) surfaces has been proposed to reduce unwanted reflections off optical surfaces, see for example, Refs. 1-3. As shown in Fig. 1, ARS surfaces are surface-relief gratings that are designed such that only the zeroth-order transmitted and reflected waves propogate. In order for no diffracted waves to propogate for all incident angles, θj, up to a maximum angle of incidence, θmax, the wavelength to surface period ratio, λ/Λ, must be larger than unity and satisfy where Max is equal to the maximum value of its arguments. Since light does not diffract when interacting with these subwavelength surface features, the optical characteristics of the system can be completely described if the structured region is represented by a film having an effective permittivity.
Holographic beam samplers for high power laser
Authors: Trudeau J.M. , Fréchette J. , Côté M. , Langlois P. , Bélanger M.P. , Galarneau P. , Vander Haeghe R.E. , Barsetti S.
Published: February 2023

Smart laser-based material processing systems require complete monitoring of the laser beam characteristics. The development of such monitoring units depends strongly on the beam sampling device employed. Beam samplers compatible with a randomly polarized 1 kW average power Nd:YAG laser has been realized by etching an holographic grating directly onto the surface of a high quality fused silica substrate [1].
Diffractive Optics for Industrial Lasers
Authors: Gruhlke Russell , Giamona Larry , Sullivan William
Published: February 2023

Theory predicts that monochromatic radiation can be focussed by a diffractive optical element to a diffraction limited focal spot with nearly 100 % efficiency. Thus, large energy densities are predicted at the focal point making diffractive optical elements well suited for application to industrial laser cutting and welding technology. To utilize this potential, Coherent, in collaboration with HoloOr, has fabricated ZnSe and GaAs diffractive optical elements designed to be used in carbon dioxide industrial laser systems. These elements exhibit high diffraction efficiency and diffraction limited focal spot sizes.
Solution to the Multiple Grooves Scattering Problem–The Fast Polarization Case
Authors: Kok Yon-Lin
Published: February 2023

The problem of electromagnetic scattering by a perfectly conducting grating has been extensively studied in the field of antennas and optics. Most of the solution forms of the Fourier series type are derived with the assumption that grating structures extend in space with an infinite periodicity. In this paper a much more practical model of the grating structure is introduced for the first time to the field of diffractive optics. The model is given as follows: A finite number of rectangular grooves of arbitrary width and depths are arbitrarily spaced and corrugated into a perfectly conducting plane forming a grooves array with an aperiodic geometry.
Laser Technologies of Diffractive Element Synthesis for Mass-Application Optical Systems
Authors: Koronkevich V.P.
Published: February 2023

Raster scanning with a laser image generator operating in a polar coordinate system is applied for recording of an arbitrary-topology diffraction structure [1]. The synthesis technology of element masks is based on the effects of thermo-chemical modifications in thin metal films (chromium, 100-200 nm thick). Nanosecond-pulse radiation causes the growth of an oxide layer, its etching rate being many times lower than the etching rate of chromium. It allows one to carry out negative recording of a mask structure [2]. The pattern transfer into glass and formation of a binary, multilevel and continuous profile is performed by means of photolithography methods [3].
Efficient Beamsplitters and Beam Deflectors for Integrated Planar Micro-optics
Authors: Walker S. J. , Jahns J. , Ailawadi N. K. , Mansfield W. M. , Mulgrew P. P. , Pastalon J. Z. , Roberts C. W. , Tennant D. M.
Published: February 2023

Diffraction gratings are of wide interest in integrated planar micro-optics to provide beamsplitting, multi-beam generation, beam deflection, beam focussing, and anti-reflection properties. Applications for integrated planar microoptics include; imaging1, clock distribution2, computing and switching systems. By using lithographic and etching techniques, multiple micro-optic elements can be integrated on a single substrate with submicron positioning accuracy. By using through wafer alignment, elements can be positioned on the substrates top and bottom surfaces. This allows the signal to travel within the substrate, in a zig-zag fashion, from one element to the next (see fig. 1). This approach is attractive because it provides a stable compact system compared to discrete bulk optics.
Simultaneous and Sequential Recording of Holographic Fan-Out Elements
Authors: Herzig H. P. , Ehbets P. , Prongué D. , Dändliker R.
Published: February 2023

Binary phase gratings, also called Dammann gratings, represent a successful technique to fabricate fan-out elements with good uniformity of the generated array of beams, but moderate efficiency (60 - 70 %). Multilevel phase gratings [1], or smooth surface relief structures [2] have been investigated yielding improved diffraction efficiencies (> 90 %). However, proper modulation at large carrier frequencies (> 1000 lines/mm) is difficult to achieve by mask projection or laser beam writing. Therefore, interferometrically recorded holograms are still of interest for realizing off-axis elements and large fan-out numbers. This paper deals with simultaneous and sequential recording of efficient fan-out elements in thick volume holograms. We have applied coupled wave theory to the special problem of regular fan-out elements.
Lamellar Gratings as Polarizing Elements for Specularly Reflected Beams
Authors: Haggans Charles W. , Li Lifeng , Kostuk Raymond K.
Published: February 2023

Reflection of light from a high spatial frequency lamellar grating at a glass-air (Θ>Θc) or glass-metal interface introduces a phase shift between the orthogonal polarization components. If a conventional incidence geometry is used (grating vector parallel to the plane of incidence), no polarization conversion occurs. Thus, gratings of this type can be used as phase compensation and retardation elements operating on a specularly reflected beam.
Beam Shaping of High-Power Laser Diode Array by Continuous Surface-Relief Elements
Authors: Ehbets P. , Herzig H. P. , Dändliker R. , Kjelberg I.
Published: February 2023

Laser diode arrays (LDAs) can generate coherent light beams of high power. Unfortunately, LDAs generate poor quality output beams, which cannot be properly collimated by conventional diode laser optics. In order to improve the optical quality of the output, Veldkamp et al. [1] have proposed different possibilities using binary optical elements. Our approach is based on the tandem component described in Ref. 2, but it uses a simple phase plate and a continuous surface relief-element for the fan-in of the N beams. Theory for the design and the realization of the diffractive optical elements (DOEs), simulated results for the performance of the system, as well as experimental results for a compact set-up will be presented.
Grating Enhanced Detection of Surface Acoustic Waves Using an Acousto-optic Modulator
Authors: Larson D. A. , Black T. D.
Published: February 2023

The sensitivity for enhanced detection of surface acoustic waves (SAW) using a traveling Bragg regime grating was found to be similar to that obtained using stationary reference gratings operating in the Raman-Nath diffraction regimes.1 An acousto-optic modulator (AOM) with a nominal frequency of 40 MHz was used to detect traveling gratings produced by SAW on a LiNbO3 substrate. The center frequency of the SAW was 34.88 MHz corresponding to a wavelength, ΛS, of 100 µm. With the AOM tuned to 38.5 MHz, the wavelength of the bulk acoustic wave, ΛB, in the flint glass modulator was also about 100 µm. The AOM was operating in the Bragg diffraction regime (Q'≈11) and the SAW in these experiments was a weakly modulated traveling grating, either cw or pulsed, operating in the Raman-Nath diffraction regime.2
Traceable Aspheric Testing Using Diamond-Machine Diffractive Null Lenses
Authors: Evans Clinton , Francis Melvyn , Morrison Donald
Published: February 2023

Figure 1 shows a 5.6 inch diameter aspheric mirror which we wish to manufacture and test. Figure 2 shows the mirror’s wavefront aberration when used with one infinite conjugate. The most significant feature of this plot is a large spherical zone of about 25 waves.
Design of Dynamic Imaging Systems using SLM based Kinoform Lenses
Authors: Tam Eddy C. , Song Qiwang
Published: February 2023

The subject of diffractive optics has been studied for many years. Some of the applications in this area are the use of Fresnel zone plates in x-ray or gamma ray imaging, modulation zone plates in laser machinery, computer generated holograms in optical interconnects and optical computing, and microlenses in laser beam and LEDs focusing. However, there is not much attention in spatial light modulator (SLM) based dynamic diffractive optical elements. In this paper, we would like to study the design of SLM based kinoform lenses in dynamic electro-optical imaging systems. The phase relief profile of a spherical lens, usually called a kinoform lens, is implemented onto a continuous phase SLM. The focal length of the kinoform lens can then be changed at the frame rate of the SLM. This dynamic lens will be incorporated with other refractive lenses to give an electro-optical imaging system which does not require any movable mechanical parts for focusing and/or zooming. More importantly, focusing/zooming can be accomplished at the frame rate of the SLM, typically in the order of 30 to 40 ms per frame for a commercially available nematic liquid crystal light modulator. This speed represents at least an order of magnitude faster than that required in a conventional focusing or zooming system based on mechanical motion of lenses.
Binary Mask Generation For Diffractive Optical Elements Using Microcomputers
Authors: O’Shea Donald C. , Beletic James W. , Poutous Menelaos
Published: February 2023

A new technique for generation of binary masks for the fabrication of diffractive optical elements is presented. This technique, which uses ordinary desktop publishing software and hardware in conjunction with a standard photoreduction camera, is much faster and less expensive than the conventional methods. The short turnaround time and low cost should give researchers a much greater degree of flexibility in the field of binary optics and enable wider application of diffractive optics technology. The paper includes examples of optical elements made by the new technique.
Methods for Diffractive Elements Surface Profile Fabrication
Authors: Poleshchuk A.G.
Published: February 2023

The progress in optics is related to wide application of computer-synthesized diffractive optical elements (DOE). The lithography technology allows one to fabricate easily a DOE with binary profile. Using a set of N = 3-4 masks one can fabricate multilevel DOE with the diffraction efficiency (DE) over 90% [1]. Another way to form a DOE profile is based on incoherent spatial filtering of a periodic mask spectrum and bleaching of the exposed film [2]. This method simplifies substantially the process of DOE fabrication because it does not involve fabrication and aligning of a set of masks. However, this method allows to fabricate only periodic DOE.
Implementation of a Packed Data Format for Production of Computer Generated Holograms by E-beam Lithography
Authors: Newman Daniel M. , Hawley Robert W. , Gallagher Neal C.
Published: February 2023

Electron beam lithography has become the method of choice for producing computer generated holograms. The demand for these high quality diffractive optics has made their fabrication much more than a research interest. Unfortunately, the electron beam machines themselves have not kept pace with the demand for this new application. The pattern data formats used with these machines were developed with the VLSI industry in mind. As a result they are not well suited for exposing the arbitrary fringe patterns found in many computer generated holograms.
Processing Error Limitations on Performance of Diffractive Optical Elements
Authors: Cox J. Allen
Published: February 2023

The use of lithographic and etching techniques to fabricate phase-only diffractive elements was first demonstrated by d’Auria et al1 and has now become popular following the improvements in the technology driven by the microelectronics industry. In the usual approach, a staircase approximation to the ideal continuous phase profile is implemented in the substrate using a binary mask-and-etch sequence in which the number of phase levels generated is a power of two. Performance is usually discussed in terms of diffraction efficiency and image quality. Dammann2 first showed how to calculate diffraction efficiency for the staircase structures using the Fourier theory. Image quality, for those diffractive elements which form images, has been modeled either using raytrace codes with an infinite index approximation or using brute-force integration of the scalar Kirchhoff equation3.
Performance of Diffractive Optics
Authors: DeSandre Lewis F. , Hodgkin Van A. , Elson J. Merle , Zhao Tianji , Macleod Angus , Buzcek Carl
Published: February 2023

Combination diffractive and refractive optical systems offer numerous and exciting possibilities as alternatives to all refractive systems. Combinations of refractive and diffractive elements can work very well together for certain applications. Also, diffractive elements can be used solo in more restricted cases such as monochromatic and narrow-field-of-view applications. Diffractive elements can be computer designed, lightweight, used to control aberrations, and used to shape the wavefront. While diffractive elements definitely have much potential for the right applications, there are some possible drawbacks. These include questions of diffraction efficiency and light scattering due to random imperfections. In this work, we propose to address some of these issues.
Phase Optimization Of Kinoforms By Simulated Annealing
Authors: Yoshikawa N. , Yatagai T.
Published: February 2023

The kinoform1 is a phase-only computer-generated hologram which has some advantages because of its high efficiency. Some studies on the optimization of the phase distribution in the kinoform has already been reported by several authors to the present2,3. In most of studies, the iterative method were chiefly adopted to optimize the phase distribution in the kinoform. However, in the iterative method, a system to be optimized may be trapped the local minimum , so that the global minimum is not always found. The optimization of a simple kinoform by the simulated annealing(SA) algorithm4 has already been studied by Turunen et al.5. The SA algorithm is a method of finding the global minimum in a system to be optimized.
Annealing Binary Fresnel Holograms for Shaped Beam Generation
Authors: Guest Clark C.
Published: February 2023

Many applications arise in optics and other regimes of electromagnetic waves that require the generation of a beam with a specified two dimensional profile. Optical power is provided in the form of a plane or spherical wave having a known amplitude profile. An optical system must then be designed to transform this input into a beam that produces the desired intensity distribution at a plane a known distance away. This distance often falls within the Fresnel diffraction regime of the optical system.
Diffraction efficiency of multi-level binary optics lenses
Authors: Southwell William H.
Published: February 2023

A kinoform surface designed to perfectly focus incident plane waves can be expressed1 by a surface sag s given by where m=0,1,2… is the zone number, gm=λm/(n1-n2) is the offset of the projected vertex plane of the mth zone from the m=0 zone, n1 is the incident refractive index, n2 is the refractive index of image space, κ=-(n1/n2)2 is the conic coefficient, and the curvature in the mth zone is given by where f is the lens focal length. Applying the condition that the path length between adjacent zones differ by one wavelength, the radial height of the zone edges or surface discontinuities is given by The longitudinal surface discontinuity em at top of the mth zone is found by equating em=s in Eq.(1) at the height ym+1 given by Eq.(3), Although an approximation to Eq.(4) is given by em≈λ/(n1-n2), the magnitude of em tends to decrease with increasing zone number m. This may be seen by observing the depths of the jumps of the smooth surface in Fig. 1.
Boundary Element Method for Analysis and Design of One-Dimensional Diffractive Optical Elements
Authors: Prather Dennis W. , Mirotznik Mark S. , Mait Joseph N.
Published: February 2023

The boundary element method (BEM) is a numerical technique to solve the boundary integral for the vector analysis of diffraction.1,2 Boundary integral methods model the interaction between an incident field and a diffractive optical element (DOE) using distributions induced on the surface of the DOE by the incident field. For a conductor the surface distribution is a current and, for a dielectric, it is a polarization field. Re-radiation from the surface distribution, in turn, generates a diffracted field. The objective of the BEM is the determination of the surface distribution given the incident field and DOE.
Mathematical Justification for the Recent Improvement of the Modal Method by Fourier Expansion
Authors: Li Lifeng
Published: February 2023

Recently, Lalanne and Morris1, and Granet and Guizal2 numerically achieved dramatic improvement in the convergence rate of the modal method by Fourier expansion (MMFE, also called the coupled-wave method) for metallic gratings in TM polarization by reformulating the algebraic eigenvalue problem. Figure 1 shows a numerical comparison between the old and new formulations for a case studied in Ref. 3. Their work convincingly proved that the cause of the slow convergence of the MMFE is not the use of the Fourier series but the way in which the Fourier series of the permittivity and reciprocal permittivity functions are used.
Single Step Fabrication of Glass Microlenses for Array and Diode Laser Applications
Authors: Fromer Neil , Lawandy N. M.
Published: February 2023

Recently, a single step technique for the fabrication of microlenses was reported, in which a laser induced thermal runaway process caused a local melting transition near the surface of a semiconductor doped glass. [1] These microlenses were produced on time scales of a fraction of a second and in a single step, a dramatic improvement over conventional fabrication techniques, where multiple processing steps and long processing times are required. Using this method, we have produced micro -elliptical lenses and demonstrated their capability to correct the output of a diode laser. In addition, microlens arrays have been produced using diffractive spot generators to irradiate the glass. Because of heat transfer effects, this approach had to be modified to produced equivalent microlenses throughout the array. The appropriate spot grating phase mask design to generate uniform arrays has been addressed and is also discussed in the work that follows.
Ion Exchange in Glass for the Fabrication of Continuous-Phase Diffractive Optical Elements
Authors: Salmio Risto-Pekka , Saarinen Jyrki , Saarikoski Henri , Turunen Jari , Tervonen Ari
Published: February 2023

Diffractive phase elements, which only modulate the phase of an incident wavefront, provide high diffraction efficiencies. Such elements can be fabricated in the form of surface-relief profiles by a variety of methods including selective etching or material deposition, and diamond turning. Binary surface-relief elements have diffraction efficiencies of the order of 30–75% depending on the symmetries of the signal, while efficiencies even in excess of 90% are only possible if one employs continuous surface profiles fabricated, e.g., by direct-write laser beam or electron-beam lithography. Then, however, accurate exposure control is needed. Continuous surface profiles can be approximated by multilevel profiles, which may be fabricated by successive lithography steps, where careful mask alignment is then required.
Diffractive Optics in Free-Space OptoElectronic Computing Systems
Authors: Marchand Philippe J. , McCormick Frederick B. , Esener Sadik C.
Published: February 2023

Optical interconnections have been shown to have advantages over electrical interconnections in terms of speed, energy, and density for global links1. In addition, the flexibility of optical interconnections permits efficient electronic layouts that can improve the performance of electrical connections in an opto-electronic computing system. Optical interconnections systems are currently a very active area of research2,3,4,5. These systems typically combine electronic circuits, opto-electronic transmitters and receivers, and optical elements. Electronic circuits are usually designed, optimized, and fabricated using standard VLSI technology. Many technologies are available for opto-electronic transmitters and receivers; in our case, we will use either Si/PLZT6,7 or Si/MQW8 technologies. Similarly, there is a wide choice of technologies available for the optical elements in the system. In this paper we first present some results on diffractive elements for Free-Space Interconnection systems fabricated using e-beam direct write technology. Then we discuss the design and optimization of the diffractive elements used in a particular free-space optical interconnection scheme: the optical transpose interconnection system (OTIS); where we have used CodeV®9 optical system design software package to design and optimize several different systems based on both refractive and diffractive micro-optic technologies. In addition, we have explored the possibility of using a volume holographic element to replace the need for a polarizing beam splitter in the system.
Integration of Diffractive Optical Elements with Vertical-Cavity Surface-Emitting Lasers
Authors: Warren M.E. , Du T.C. , Wendt J.R. , Vawter G.A. , Lear K.L. , Kilcoyne S.P. , Carson R.F. , Seigal P.K. , Crawford M. Hagerott , Hou H. , Schneider R.P.
Published: February 2023

Vertical-cavity surface-emitting lasers (VCSELs) are very desirable sources for a variety of optical system applications. In particular, the inherent planarity of arrays of VCSELs makes them ideal for compact 3-dimensional optical interconnect systems1. Despite smaller beam divergence than edge emitting lasers, spreading of the beam emerging perpendicular to the surface of the VCSEL limits the range of free space transmission, reduces the device density in an array and can introduce cross-talk. Although an external optical system using a separate lens array is a possible solution, the idea may be impractical or expensive due to constraints such as space limitations or the additional need for an optomechanical system to position the lenses. An alternative approach is the integration of high efficiency diffractive optics and VCSELs on a single transparent substrate. Such a compact source is also very attractive for miniature optical instrumentation applications. Integrating diffractive optical elements with substratemitting VCSELs provides a method for manipulating the propagation properties of the exiting beams2. With diffractive structures, a broad range of optical elements can be easily designed and fabricated and high diffraction efficiencies can be achieved with current processing technologies.
Fabrication of continuous-relief micro-optics: progress in laser writing and replication technology
Authors: Gale M.T. , Hessler Th. , Kunz R.E , Teichmann H.
Published: February 2023

Laser writing technology for the fabrication of continuous-relief micro-optical elements is being developed at a number of institutes worldwide [1,2]. It represents a very powerful and flexible fabrication technique and fits well to replication technology in which the resist surface-relief microstructure can be electroformed and replicated into plastic material. Fig. 1 illustrates the essential production steps involved.
Replication of continuous-relief diffractive optical elements by conventional CD injection molding techniques
Authors: Nikolajeff Fredrik , Holmér Anna-Karin , Jacobsson Stellan , Hård Sverker , Billman Åke , Lundbladh Lars , Lindell Curt
Published: February 2023

Diffractive optical elements (DOEs) are realized either as continuous surface-relief microstructures (e.g. by direct-write electron beam lithography or direct laser writing) or as binary or multilevel reliefs (mostly using semiconductor fabrication technology). In general, the optical performance (especially efficiency) of continuous-reliefs is superior to that of their binary counterparts. One very important feature of DOEs is their ability to be replicated using techniques such as embossing, casting or molding1. Although the manufacture cost of one original DOE is relatively high, the piecewise cost is dramatically reduced when large series of one specific DOE is wanted (e.g. in telecommunication). A method particularly well suited for massproduction of DOEs is injection molding2,3. We will describe the process of replicating continuous-relief DOEs by conventional CD injection molding, report on successfully replicated DOEs and discuss the fidelity of the process.
Multiple Order Delay Holograms for Polarization and Color Selectivity
Authors: Xu Fang , Tyan Rong-Chung , Ford Joseph E. , Fainman Yeshayahu
Published: February 2023

Diffractive optical elements constructed as phase only computer generated holograms (CGHs) are attractive for numerous applications in photonics and optoelectronics. A conventional diffractive optical element (DOE) has a maximum phase delay of 2π between pixels. Therefore, the required etch depth is, in general, shallow (< wavelength λ, see Fig. 1a). These DOEs are relatively insensitive to the polarization and wavelength of the reconstruction field compared to volume gratings. Previously we demonstrated polarization selective diffractive optical elements using two birefringent LiNbO3 substrates with different diffractive microstructures on the interior.1,2 The required etch depths on both substrates are deeper than that in a conventional DOE because the substrates birefringence is relatively small (see Fig. 1b). Another approach to achieve the same functionality is based on deep etch structure (see Fig. 1c) that corresponds to multiple periods of phase delays (also called modular 2mπ) using a single birefringent substrate, as first proposed in reference 1 and later in reference 3. This approach may reduce the cost and simplify the fabrication process of such polarization selective diffractive optical elements. In the following we report the design, fabrication and characterization of multiple order delay (MOD) holograms that posses dual functionality in polarization or color.
Optical Design Comparison of 60° Eyepieces One with Aspherics and One with A Diffractive Surface Final Results
Authors: Knapp Wayne , Volk Brian , Tatian Berge , Blough Gary , Michaels Robert
Published: February 2023

Eyepiece optical designs were developed for a wide angle eyepiece with a large exit pupil and eye relief. In addition to the design criteria listed below in Table 1, one design was of a conventional configuration (aspherics and plastics permitted) and the other design was to include a diffractive optic.
Sub-nanometer linewidth resonant grating filters
Authors: Peng Song , Morris G. Michael
Published: February 2023

Narrowband filters are important optical components that have numerous applications. Conventional interference narrowband filters suffers low peak efficiency due to the roughness of the film coatings especially the roughness of the spacer layers. The minimum linewidths of interference filters are typically 1 nm for the visible regime, while the peak efficiencies are less than 40%. Spectral stability of interference filters is poor because spacer layers absorb water vapors and cause shifting of the peak wavelength. Usually the coatings have to be sandwiched in between two substrates, which are then sealed along the side. In addition, narrowband interference filters are structure-complex; 60 layers are not uncommon for 1 nm interference filters. The large number of layers imposes great difficulty in the use of advanced film deposition techniques such as chemical vapor deposition (CVD) methods.
Giant Microoptics: Wide Applications in Liquid Crystal Display (LCD) Systems
Authors: Aoyama Shigeru , Kurahashi Tsuyoshi , Uchida Daidou , Shinohara Masayuki , Yamashita Tsukasa
Published: February 2023

Microoptic devices1,2) as shown in fig.1 are becoming standard optical components by recent development in optical imaging systems and fiber communication systems because of 2-D configuration facility and mass productivity using replicating technique3). In particular, LCD systems have been grown up very fast in these few years and will be a promising industrial field of microoptic devices. For this purpose, area size must be increased from a few mm to a few 10 cm, while μm feature size is still remained, and this is called giant microoptics.
Color Separation Echelon Gratings
Authors: Stern Margaret B. , Swanson Gary J.
Published: February 2023

Color discrimination by wavelength bands has a large number of military and commercial applications. In the infrared portion of the spectrum, wavelength separation allows better temperature discrimination of thermally emissive objects. [1] In the visible portion of the spectrum, a device which separates white light into red, green, and blue wavebands without loss of energy could increase the efficiency of color sensors. An echelon-like grating structure [2,3] separates electromagnetic radiation of different wavelengths according to diffraction order rather than by dispersion within one diffraction order as would be the case for a conventional prism-type grating, as shown schematically in Figure 1.
Microlens Lithography
Authors: Völkel R. , Herzig H. P. , Nussbaum Ph. , Singer W. , Dändliker R.
Published: February 2023

The future demands for flat panel display (FPD) manufacturing is a resolution of 3-5 μm for large substrates of 550 × 650 mm2 size. Standard lithographic techniques, like wafer stepping or proximity printing can be used. Unfortunately, these methods have some severe drawbacks which significantly increase the fabrication costs. Using a wafer stepper, the small printing area will cause numerous exposure steps. The stepping has to be very accurate, because stitching errors can be easily seen in the display pattern. Using a proximity printer, the substrate is set some 20-50 μm behind the mask to achieve a resolution of 3-5 μm. This is not an easy task for large substrates. The costs for these highly planar substrates are immense. A direct contact may easily damage the expensive photomask.
Interferometric Tests for Micro-Optics
Authors: Lindlein N. , Schwider J.
Published: February 2023

Micro-optics comprises different kinds of optical elements. This paper will mainly deal with the testing of microlenses, not of mirrors, prisms and other microoptical devices. Microlenses can be classified into two types: refractive and diffractive lenses. Since the diffractive lenses are normally computer generated it is not necessary to test their global optical function, only the microstructure has to be measured. In the case of refractive microlenses there are several properties which have to be determined: paraxial parameters (e.g. focal length, diameter), surface quality (deviations from the ideal form) and wave aberrations. The measurement of these parameters with the help of interferometers in reflected and transmitted light, as well as the advantages and problems of these interferometers, will be discussed.
Evaluation of Wavefront Sensors Based on Etched Microlenses
Authors: Pierson R. E. , Bishop K. B. , Chen E. Y. , Neal D. R. , McMackin L.
Published: February 2023

Since etched microlenses are produced by digital technology, it is inherently easy to fabricate optics customized for a particular application. However, optimization of wavefront sensors requires an ability to predict their complex behavior. In previous work,1,2 we demonstrated binary microlens arrays for wavefront sensing in a visible wavelength tomographic imaging system. An eight-view tomographic system based on microlens array sensors is now operational and is described in a separate paper at this conference.3 The current paper addresses error budgeting and optimal design for wavefront sensors; it describes modeling and test procedures and illustrates one design approach.
Submicron gratings with dielectric overcoat: performance and stability
Authors: Heine C. , Morf R. H. , Gale M. T.
Published: February 2023

Submicron gratings show increasing potential in applied optics, often presenting attractive alternatives to thin film technology solutions. Gratings on light-weight plastic materials can replace heavy and expensive glass devices. Embossing techniques can be used for cheap mass production. The coating of gratings with thin films leads to additional degrees of freedom for component design. For practical applications, it is important not only to investigate the possibilities of such structures, but also the limiting factors such as fabrication considerations and stability properties.
High Efficiency Dielectric Reflection Gratings
Authors: Shore B. W. , Perry M. D. , Britten J. A. , Boyd R. D. , Feit M. D. , Nguyen H. , Chow R. , Loomis G. , Li Lifeng
Published: February 2023

We discuss examples of designs for all-dielectric high-efficiency reflection gratings that tolerate high intensity laser pulses and are, in theory, capable of placing 99% of the incident light into a single diffraction order. The designs are based on placing a dielectric transmission grating atop a high-reflectivity multilayer dielectric stack. We comment on the connection between transmission gratings and reflection gratings and note that many combinations of gratings and multilayer stacks offer high efficiency. Thus it is possible to attain secondary objectives in the design. We describe examples of such designs aimed toward improving fabrication and lowering the susceptibility to laser-induced damage.
High efficiency fast diffractive lens for beam coupling
Authors: Sheng Yunlong , Feng Dazeng
Published: February 2023

Diffractive lenses for laser diode beam focusing collimating and coupling have wide applications. Large numerical aperture and high light efficiency are important issues for the coupling lenses. Numerical aperture of a typical laser diode beam can be as large as NA ~ 0.5. To capture the highly divergent beam the lens must have a low F-number of F/1 ~ F/2. Coupling the laser beam into an optic fiber with an acceptance angle of NA ~ 0.1 - 0.2 needs even larger numerical aperture of the lens.
Fabrication and Experiment of Diffractive Phase Element That Implements Wavelength Demultiplexing and Focusing
Authors: Dong Bizhen , Zhang Guoqing , Yang Guozhen , Gu Benyuan , Zheng Shihai , Li Dehua , Chen Yansong
Published: February 2023

Recently, the diffractive optics has extensively attracted interest of researchers because diffractive optical elements (DOE’s) can incorporate several optical functions in a single optical element.[1–4] This is important in a number of areas such as integrated optics, optical computing, optical sensors, and so on. For example, one can design diffractive optical elements to perform wavelength multiplexing/demultiplexing, and focusing. Various designs and fabrication schemes for DOE’s that modulate only the phase of an incident lightwave have been proposed. In this paper we present the design and fabrication of diffractive phase element (DPE) that incorporates simultaneous wavelength demultiplexing and focusing in the optical system illuminated by a light beam with three wavelength components. Optical lithography and reactive-ion etching are used to fabricate the surface-relief structure with 8 levels. Experiments demonstrate the feasibility of three wavelength demultiplexing and focusing simultaneouslly.
Off-axis Talbot effect and array generation in planar optics
Authors: Testorf Markus , Jahns Jürgen , Khilo Nikolay A. , Goncharenko Andrey M.
Published: February 2023

Recently, planar optics was introduced as a concept for the micro integration of free space optics1. For the planar optics approach passive optical elements are arranged on the surface of a thick transparent substrate. The light signal travels within the substrate along a folded zigzag path, reflected at the surfaces of the substrate. Since planar optics was first proposed, various applications were successfully demonstrated, like integrated split and shift modules2 or integrated optical imaging systems3.
Analysis of Focal Tolerance and Fine Pattern Resolutions Formed by Phase Conjugation in Dichromated Gelatin Hologram
Authors: Im Yong Seok , Lee Young Lak , Kwak Chong Hoon , Choe Ok Shik
Published: February 2023

Submicrometer photolithography necessitates high resolution imaging system. Optical holography is one of the promising candidates for realizing such high resolution imaging systems. Several optical system utilizing holograms have been demonstrated until now including far-field holograms, image holograms, and focused image holograms. In order to achieve the required high resolution, there is to decreasing the wavelength or to increasing the numerical aperture. Two fundamental parameters limiting an optical system are the numerical aperture, NA, and the size of the image field of the imaging optics.1 For a given wavelength, the resolution is improved by increasing the numerical aperture. As a result, the increasing NA lead to decreasing the focal tolerance. In this paper we present the high resolution holographic imaging system using a focused imaging hologram with phase conjugate wave and demonstrated a long focal tolerance of an image.
Holographic Interferometry Methods for Conducting Stress Analysis on Quartz Crystal Components
Authors: Brosig Jill A.
Published: February 2023

The technique of holographic interferometry has aided in Motorola’s Quartz Products Division’s continuous pursuit of higher quality quartz crystal components. QPD’s portfolio consists of several models of quartz crystals, which are sold as resonators, oscillators, and filters. The crystal frequency for the various products ranges from 12 MHz to 100 MHz.
Measurement and Analysis of Compound Amplitude and Phase Holographic Gratings
Authors: Wang Y. J. , Fiddy M. A. , Teng Y. Y. , Pommet D. A. , Malley L.
Published: February 2023

A hologram on which an interference pattern is recorded, appears transparent after exposure, developing and bleaching. However, these types of holographic transparencies are found to have both some periodic variations of optical density and surface relief when measured using microdensitometer and profilometer. We refer to this kind of holographic grating as a compound hologram, i.e. it contains variations in both amplitude and phase.
Effect of spatial coherence on photolithographic phase mask performance
Authors: Salik Boaz , Yariv Amnon
Published: February 2023

We show that, contrary to the prevailing trend in photolithography, increasing the spatial coherence of illumination does not necessarily improve the performance of phase masks in enhancing resolution and focal depth. Simulations and experiments show that for large (aperiodic) phase masks, the optimal coherence diameter is determined by the minimum resolvable feature size, not the size of the mask. This is due to a trade-off between the destructive interference of adjacent features under coherent illumination and the larger effective aperture of incoherent illumination.