skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Predictive models for the Strehl ratio of diamond-machined optics
This paper provides a practical connection between the Strehl ratio as an optical performance metric and manufacturing parameters for diamond-machined optics. The choice of fabrication parameters impacts residual midspatial frequency groove structures over the part’s surface, which reduce optical performance. Connections between the Strehl ratio and the fabrication parameters are studied using rigorous Rayleigh–Sommerfeld simulations for a sample optical system. The connections are generalized by incorporating the shape of diamond-machined groove structures and the effects of optical path differences for both transmissive and reflective optics. This work validates the analytical representation of the Strehl ratio as a Fourier transform of a probability density that relates to surface errors. The result is a practical tool that can be used to guide the choice of machining parameters to achieve a targeted optical performance. © 2019 Optical Society of America https://doi.org/10.1364/AO.58.003272  more » « less
Award ID(s):
1822049 1338877
PAR ID:
10161238
Author(s) / Creator(s):
; ; ;
Date Published:
Journal Name:
Applied optics
Volume:
58
Issue:
12
ISSN:
1559-128X
Page Range / eLocation ID:
3272-3276
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, Proceedings of the 20th euspen International Conference and Exhibition)
    Single crystal calcium fluoride (CaF2) is widely used for transmissive optics in the ultraviolet and vacuum ultraviolet (UV and VUV) spectral regions because of its high optical transmission. Optical components made of CaF2 are usually manufactured by precision machining to generate high quality surfaces with low surface roughness. However, the influence of the clamping technique on the resulting surface roughness of diamond machined CaF2 has not been reported. In this research, two clamping techniques, vacuum clamping and gluing with wax, are used in off-axis diamond turning experiments with zero degree and negative rake angle diamond tools. Surface characterization by white light interferometry and atomic force microscopy show surfaces with low surface roughness. Furthermore, a significant influence of the clamping technique on the generated surface topography is observed. 
    more » « less
  2. ; ; (, Journal of Manufacturing Science and Engineering)
    null (Ed.)
    Abstract This article is written as a tribute to Professor Frederick Fongsun Ling 1927–2014. Single-point diamond machining, a subset of a broader class of processes characterized as ultraprecision machining, is used for the creation of surfaces and components with nanometer scale surface roughnesses, and submicrometer scale geometrical form accuracies. Its initial development centered mainly on the machining of optics for energy and defense related needs. Today, diamond machining has broad applications that include the manufacture of precision freeform optics for defense and commercial applications, the structuring of surfaces for functional performance, and the creation of molds used for the replication of a broad range of components in plastic or glass. The present work focuses on a brief review of the technology. First addressed is the state of current understanding of the mechanics that govern the process including the resulting forces, energies and the size effect, forces when cutting single crystals, and resulting cutting temperatures. Efforts to model the process are then described. The workpiece material response when cutting ductile and brittle materials is also included. Then the present state of the art in machine tools, diamond tools and tool development, various cutting configurations used, and some examples of diamond machined surfaces and components are presented. A discussion on the measurement of surface topography, geometrical form, and subsurface damage of diamond machined surfaces is also included. 
    more » « less
  3. ; ; (, Proceedings of the 20th euspen International Conference and Exhibition)
    Single-crystal calcium fluorite (CaF2) is widely used for transmissive optics in ultraviolet and vacuum ultraviolet (UV and VUV) wavelength applications because of its exceptional transmission performance. Generally, products using CaF2 are manufactured through finishing processes such as chemo-mechanical polishing (CMP), magnetorheological finishing (MRF) or ion-beam figuring (IBF) after performing precision cutting and grinding processes for profiling. However, CaF2 is known as a brittle material with high anisotropy, and subsurface damage is induced by each cutting process. But, the effects of surface integrity on the optical and functional performance of precision machined CaF2 has not been reported yet. In this research, a newly developed multiaxial adjustment system that can precisely align specimens is used in single-axis orthogonal cutting experiments with zero degree and negative rake angle diamond radius tools to prevent pre-machining and thus pre-damaging of single-crystal CaF2 specimens. Cutting forces evaluation via piezoelectric dynamometer acquisition as well as surface analysis by atomic force microscopy and white light microscopy has been performed. Finally, smooth surfaces due to ductile material removal mechanisms could be determined on all machined specimen surfaces. 
    more » « less
  4. ; ; ; ; ; (, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation V)
    Geyl, Roland; Navarro, Ramón (Ed.)
    With the advancements of ultra-high-precision micro-optics fabrication technologies, it is now possible to fabricate integral field units (IFUs) with slicer mirror width of 30 m or less. This paper describes a 36-um machined image slicer IFU (MISI-36) for the Diffraction-Limited near-IR Spectropolarimeter (DL-NIRSP) of the Daniel K. Inouye Solar Telescope (DKIST). MISI-36 has a unique 2-section image slicer design, and is consists of a monolithic image slicer block with 112 micro slicer mirrors, a parabolic collimator, a monolithic flat mirror array consists of 112 fold mirrors, and a monolithic spherical mirror array consists of 112 spherical mirrors. We have successfully fabricated a prototype device using Canon Inc.’s diamond-cutting CNC, and conducted a preliminary performance evaluation using an experimental bench-top spectrograph similar to the spectrograph of DL-NIRSP. We will present the optical design and optical performances of the MISI-36 prototype. 
    more » « less
  5. ; ; ; ; ; ; ; ; ; ; et al (, Adaptive Optics Systems VIII)
    Schmidt, Dirk; Schreiber, Laura; Vernet, Elise (Ed.)
    We present evaluations of the Keck Telescope’s adaptive optics (AO) performance on Milky Way Galactic center imaging and spectroscopic observations using three different AO setups: laser guide star with infrared (IR) tip-tilt correction, laser guide star with visible tip-tilt correction, and infrared natural guide star with a pyramid wavefront sensor. Observations of the Galactic Center can utilize a bright IR tip-tilt star (K′ = 7.4 mag) for corrections, which is over 10 arcseconds closer than the optical tip-tilt star. The proximity of this IR star enables the comparison of the aforementioned AO configurations. We present performance metrics such as full-width-at-half-maximum (FWHM), Strehl ratio, and spectral signal to noise ratio and their relations to atmospheric seeing conditions. The IR tip-tilt star decreases the median spatial FWHM by 31% in imaging data and 30% in spectroscopy. Median Strehl for imaging data improves by 24%. Additionally, the IR star removes the seeing dependence from differential tip-tilt error in both imaging and spectroscopic data. This evaluation provides important work for ongoing upgrades to AO systems, such as the Keck All sky Precision Adaptive Optics (KAPA) upgrade on the Keck I Telescope, and the development of new AO systems for extremely large telescopes. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email