ASPE 2015 Summer Topical Meeting

Precision Interferometric Metrology
July 8 – 10, 2015
The Golden Hotel
Golden, Colorado, USA

Meeting Organizers:
Chris J. Evans,
University of North Carolina at Charlotte
Peter J. de Groot, Zygo Corporation
Angela D. Davies, University of North Carolina at Charlotte
Jack Clark, Surface Analytics, LLC; Colorado State University

Program & Schedule | Invited Speakers | Presentations | Evening Session | NIST Tour

Golden Sites | Adventure Tours | Committee | Photo Album

Golden, Colorado – Last week, July 7-10, the 5th ASPE Topical Meeting on Precision Interferometric Metrology was held in beautiful Golden, Colorado. This special topical meeting, which takes place every 5 years, brings together specialists and practitioners from industry, government and academia in an ideal forum for the exchange of ideas.

Organizers Chris Evans, Angela Davies, Jack Clark and Peter de Groot composed a schedule that began with a pre-conference tour of the NIST Boulder on Tuesday, including laboratories exploring applications of femto-second lasers for environmental spectroscopy and distance measurement and facilities for fabrication of superconductor and nanoelectronic circuits. The next three days followed the workshop-style format enjoyed in past meetings, with an emphasis on discussion in a relaxed atmosphere. The first full day of presentations concluded with a sponsored conference dinner, and the second day included a free afternoon for discovering the town of Golden, and an evening session with both an open agenda and an open bar. Friday morning concluded the conference, capped by a group luncheon prior to departure to the airport or to the Rocky Mountains to enjoy the Colorado countryside.

The invited papers give some idea of the diversity of technologies and applications discussed during the meeting. Klaus Freischlad delivered the keynote, describing his several years of experience in developing surface topography instruments with exceptionally low noise, using his solid understanding of optical coherence and precision instrument design. Esther Baumann described innovative work in the 3D measurement of objects using swept-wavelength techniques, leveraging a frequency comb laser for in-situ calibration. Jon Pratt captured everyone’s attention with his entertaining and instructive “canonical ideas” in precision engineering, using the Watt balance as a supremely challenging example. Jim Burge outlined the impressive work in optical metrology of large telescope mirrors using both interferometric and non-interferometric techniques such as deflectometry, which is challenging interferometry for the title of “gold standard” for in process, mid spatial frequency analysis.  Jack Clark filed his front-line report on the use of the new areal surface parameters and advanced interferometric instrumentation to improve surface quality and performance for applications ranging from improving medical devices to automotive component manufacture. Vivek Badami outlined the state of the art in fine-positioning interferometry, covering laser displacement measurement for photolithography stages, the new generation of heterodyne optical encoders, and distributed fiber-optic position sensors with extraordinary lifetime and performance.

A wide range of contributed papers covered the microscopic to the astronomical scale, including Fabry-Perot accelerometer standards (Felipe Guzman), sub-wavelength diffraction gratings for optomechanics (John Lawall), point-scanning CMM technology for asphere metrology (Andreas Beutler), precision measurements of refractive index (Patrick Egan and Xiangzhi Yu) and challenges in lithography optics manufacture (Frank Riepenhausen). Kate Medicus provided a partial uncertainty analysis for asphere measurements with holographic null correctors—a topic that was revived during the evening discussion session. Also during the evening session, John Ellis held a vote to finally settle the debate over life’s most important questions: (1) Homodyne or heterodyne and (2) HeNe, doubled solid state or semiconductor lasers. The final vote tally will be disclosed at the next meeting—we’ll see you there in five years!