Course Description This is an advanced course in which we explore the field of Statistical Optics. Topics covered include such subjects as the statistical properties of natural (thermal) and laser light, spatial and temporal coherence, effects of partial coherence on optical imaging instruments, effects on imaging due to randomly inhomogeneous media, and a statistical treatment of the detection of light. Development of this more comprehensive model of the behavior of light draws upon the use of tools traditionally available to the electrical engineer, such as linear system theory and the theory of stochastic processes.

http://ieeexplore.ieee.org/iel5/3/23094/01073023.pdf

Statistical optics

THE OPTO-MECHANICAL DESIGN PROCESS Introduction Conceptualization Performance Specifications and Design Constraints Preliminary Design Design Analysis and Computer Modeling Error Budgets and Tolerances Experimental Modeling Finalizing the Design Design Reviews Manufacturing the Instrument Evaluating the End Product Documenting the Design References ENVIRONMENTAL INFLUENCES Introduction Parameters of Concern Environmental Testing of Optics References OPTO-MECHANICAL CHARACTERISTICS OF MATERIALS Introduction Materials for Refracting Optics Materials for Reflecting Optics Materials for Mechanical Components Adhesives Sealants Special Coatings for Opto-Mechanical Materials Techniques for Manufacturing Opto-Mechanical Parts References MOUNTING INDIVIDUAL LENSES Introduction Considerations of Centered Optics Cost Impacts of Fabrication Tolerances Lens Weight and Center of Gravity Location Mounting Individual Low-Precision Lenses Mountings for Lenses with Curved Rims Mountings Interfacing with Spherical Surfaces Elastomeric Mountings for Lenses Mounting Lenses on Flexures Alignment of the Individual Lens Mounting Plastic Lenses References MOUNTING MULTIPLE LENSES Introduction Multielement Spacing Considerations Examples of Lens Assemblies with No Moving Parts Examples of Lens Assemblies Containing Moving Parts Lathe Assembly Techniques Microscope Objectives Assemblies Using Plastic Parts Liquid Coupling of Lenses Catadioptric Assemblies Alignment of Multi-Lens Assemblies Alignment of Reflecting Telescope Systems References MOUNTING WINDOWS AND FILTERS Introduction Conventional Window Mounts Special Window Mounts Mounts for Shells and Domes Conformal Windows Filter Mounts Windows Subject to a Pressure Differential References DESIGNING AND MOUNTING PRISMS Introduction Geometric Relationships Designs for Typical Prisms Kinematic and Semikinematic Prism Mounting Principles Mounting Prisms by Clamping Mounting Prisms by Bonding Flexure Mounts for Prisms References DESIGN AND MOUNTING SMALL, NONMETALLIC MIRRORS, GRATINGS, AND PELLICLES Introduction General Considerations Semikinematic Mountings for Small Mirrors Mounting Mirrors by Bonding Flexure Mounts for Mirrors Multiple-Mirror Mounts Mountings for Gratings Pellicle Design and Mounting References LIGHTWEIGHT NONMETALLIC MIRROR DESIGN Introduction Material Considerations Core Cell Configurations Cast Ribbed Substrates Slotted-Strut and Fused Monolithic Substrates Frit-Bonded Substrates Low-Temperature Bonded Substrates Machined-Core Substrates Contoured-Back Solid Mirror Configurations Thin Face Sheet Mirror Configurations Scaling Relationships for Lightweight Mirrors References MOUNTING LARGE, HORIZONTAL-AXIS MIRRORS Introduction General Considerations of Gravity Effects V-Type Mounts Multipoint Edge Supports The Ideal Radial Mount Mercury Tube Mounts Strap and Roller-Chain Mounts Push-Pull Mounts Comparison of Dynamic Relaxation and Finite-Element Analysis Techniques References MOUNTING LARGE VERTICAL-AXIS MIRRORS Introduction Ring Mounts Air Bag (Bladder) Mounts Multiple-Point Supports Metrology Mounts References MOUNTING LARGE, VARIABLE-ORIENTATION MIRRORS Introduction Mechanical Flotation Mounts Hydraulic/Pneumatic Mounts Center-Mounted Mirrors Mounts for Double-Arch Mirrors Bipod Mirror Mounts Thin Face Sheet Mirror Mounts Mounts for Large Space-Borne Mirrors References DESIGN AND MOUNTING OF METALLIC MIRRORS Introduction General Considerations of Metal Mirrors Aluminum Mirrors Beryllium Mirrors Mirrors Made from Other Metals Mirrors with Foam and Metal Matrix Cores Plating of Metal Mirrors Single-Point Diamond Turning of Metal Mirrors Conventional Mountings for Metal Mirrors Integral Mountings for Metal Mirrors Flexure Mountings for Larger Metal Mirrors Interfacing Multiple SPDT Components to Facilitate Assembly and Alignment References OPTICAL INSTRUMENT STRUCTURAL DESIGN Introduction Rigid Housing Configurations Modular Design Principles and Examples A Structural Design for High Shock Loading Athermalized Structural Designs Geometries for Telescope Tube Structures References ANALYSIS OF THE OPTO-MECHANICAL DESIGN Introduction Failure Predictions for Optics Stress Generation at Opto-Mechanical Interfaces Parametric Comparisons of Annular Interface Types Bending Effects Due to Offset Annular Contacts Effects of Temperature Changes Effects of Temperature Gradients Stresses in Cemented and Bonded Optics Due to Temperature Changes Some Effects of Temperature Changes on Elastomerically Mounted Lenses References APPENDIX A: UNITS AND THEIR CONVERSION APPENDIX B: SUMMARY OF METHODS FOR TESTING OPTICAL COMPONENTS AND OPTICAL INSTRUMENTS UNDER ADVERSE ENVIRONMENTAL CONDITIONS APPENDIX C: HARDNESS OF MATERIALS APPENDIX D: GLOSSARY INDEX

Opto-mechanical systems design

An adaptive optics scanning laser ophthalmoscopes is introduced to produce non-invasive views of the human retina. The use of dual deformable mirrors improved the dynamic range for correction of the wavefront aberrations compared with the use of the MEMS mirror alone, and improved the quality of the wavefront correction compared with the use of the bimorph mirror alone. The large-stroke bimorph deformable mirror improved the capability for axial sectioning with the confocal imaging system by providing an easier way to move the focus axially through different layers of the retina.

High-resolution adaptive optics scanning laser ophthalmoscope with multiple deformable mirrors

Femtosecond laser fabrication of controlled three dimensional structures deep in the bulk of diamond is facilitated by a dual adaptive optics system. A deformable mirror is used in parallel with a liquid crystal spatial light modulator to compensate the extreme aberrations caused by the refractive index mismatch between the diamond and the objective immersion medium. It is shown that aberration compensation is essential for the generation of controlled micron-scale features at depths greater than 200 μm, and the dual adaptive optics approach demonstrates increased fabrication efficiency relative to experiments using a single adaptive element.

https://www.eng.ox.ac.uk/som/publications/dualAODiamond.pdf

Three dimensional laser microfabrication in diamond using a dual adaptive optics system

The past few decades have witnessed growing research interest in developing powerful nanofabrication technologies for three-dimensional (3D) structures and devices to achieve nano-scale and nano-precision manufacturing. Among the various fabrication techniques, focused ion beam (FIB) nanofabrication has been established as a well-suited and promising technique in nearly all fields of nanotechnology for the fabrication of 3D nanostructures and devices because of increasing demands from industry and research. In this article, a series of FIB nanofabrication factors related to the fabrication of 3D nanostructures and devices, including mechanisms, instruments, processes, and typical applications of FIB nanofabrication, are systematically summarized and analyzed in detail. Additionally, current challenges and future development trends of FIB nanofabrication in this field are also given. This work intends to provide guidance for practitioners, researchers, or engineers who wish to learn more about the FIB nanofabrication technology that is driving the revolution in 3D nanostructures and devices.

Recent advances in focused ion beam nanofabrication for nanostructures and devices: fundamentals and applications

Two kinds of algorithm for an adaptive optics (AO) system that uses two deformable mirrors (DMs), one with large stroke and the other with high spatial frequency, to correct different aberrations are described. The algorithms are based on modal method and direction-gradient method, respectively. Numerical simulations for the algorithms have been made. The simulation results indicate that the two DMs in the AO system can correct different aberrations with different characteristics, and the closed-loop performance of a double-DM AO system will be almost the same as that of an AO system that uses a single DM with an ideal stroke.

Double-deformable-mirror adaptive optics system for phase compensation.

A 127-element adaptive optical system has been developed and integrated into a 18-m astronomical telescope in September 2009 In addition, the first light on a high-resolution imaging for stars has been achieved (September 23, 2009) In this letter, a 127-element adaptive optical system for 18-m telescope is described briefly Moreover, star observation results in the first run are reported Results show that the angular resolution of the system after adaptive optics correction can attain 01 arcsec, which approaches the diffraction limit of 18-m telescope at 700-900 nm band

First light on the 127-element adaptive optical system for 1.8-m telescope

An optimized dwell time algorithm for magnetorheological finishing (MRF) is discussed. Based on the D-shape of the removal function of MRF, an optimized non-negative least-squares method is introduced to get dwell time from a linear matrix equation transferred from the de-convolution operation. Moreover, one kind of general surface error map extension is developed for any shape of optics to obtain a more precise optical surface in MRF. The simulation results show that the non-negative least-squares method of the constrained generalized minimal residual (GMRES) method with adaptive Tikhonov regulation is much faster to get highly stable dwell time distribution. In combination with the general surface error map extension, the peak to valley (PV) and root mean square (RMS) of the surface error of the diameter 400 mm converge from 184.41 and 21.26 nm to 7.56 and 0.632 nm with the consistency of the edge and the aperture inside. Finally, a fabricating experiment proves the validity of the optimized algorithm. Therefore, the algorithm developed and presented in this paper can facilitate the MRF process effectively.

Optimized dwell time algorithm in magnetorheological finishing

A new method for testing aspheric surfaces by annular subaperture stitching interferometry is introduced. It can test large-aperture and large-relative-aperture aspheric surfaces at high resolution, low cost, and high efficiency without auxiliary null optics. The basic principle of the method is described, the synthetical optimization stitching model and effective algorithm are established based on simultaneous least-square fitting. A hyperboloid with an aperture of 350 mm is tested by this method. The obtained peak-to-valley (PV) and root-mean-square (RMS) values of the surface error after stitching are 0.433'lambda' and 0.052'lambda' ('lambda' is 632.8 nm), respectively. The reconstructed surface map coincides with the entire surface map from null test, and the difference of PV and RMS errors between them are 0.031'lambda' and 0.005'lambda', respectively. This stitching model provides another quantitive method for testing large aspheric surfaces besides null compensation.

Measurement of large aspheric surfaces by annular subaperture stitching interferometry

The Fresnel Zone Plate (FZP) is widely used in a variety of applications. However, the most concerning drawback of the FZP is its low diffraction efficiency limited by fabrication capability. The diffraction efficiency of an FZP with a surface-relief profile can reach 100% at a specified diffracted order, however, this is difficult to engineer in a precise manner. In this paper, a hybrid-level FZP (HLFZP) is proposed to maximize the diffraction efficiency under a certain lithography condition. To theoretically verify this enhancement, the diffracted field of the HLFZP is derived by establishing a diffraction model. According to different machining capabilities, the design criteria for the level number distribution on the HLFZP are presented. Simulated results show significant improvement in imaging quality while comparing the diffraction efficiency of the specifically designed 8-4-2 HLFZP to that of the traditional 2-level FZP. Fabrication processes for the 8-4-2 HLFZP are developed, with experimental results indicating that the diffraction efficiency could be improved by 54% using the proposed HLFZP, compared to the traditional 2-level FZP. The root mean square (RMS) of the wavefront error for the 8-4-2 HLFZP is 1/20λ (λ = 632.8 nm), and imaging results are good as the predicted results. It is concluded that the proposed hybrid-level method is also promising for improving the diffraction efficiency of other diffractive optical elements.

Xuejun Zhang

Papers

Double-deformable-mirror adaptive optics system for phase compensation.

First light on the 127-element adaptive optical system for 1.8-m telescope

Optimized dwell time algorithm in magnetorheological finishing

Measurement of large aspheric surfaces by annular subaperture stitching interferometry

Hybrid-level Fresnel zone plate for diffraction efficiency enhancement