Tag Archives: Research

New Papers Online

Papers by Chen Wang and Bill Green have appeared in their final form online. Chen’s paper, Data Age Error Compensation for Nonconstant Velocity Metrology, was recently accepted in IEEE Transactions on Instrumentation and Measurement. Bill’s paper, with a PhD student James Corsetti from Optics, was recently accepted and published by Applied Optics. This paper is on Simultaneous interferometric measurement of linear coefficient of thermal expansion and temperature-dependent refractive index coefficient of optical materials. Links to both papers can be found on the publications page. Nice job and congratulations!

Bill Green has co-author paper accepted

Bill Green, Mechanical Engineering Undergraduate Student, has had a paper accepted as a co-author by Optical Engineering. This is Bill’s first time co-authoring a paper. Additionally, Bill will be presenting his work on thermal expansion and dn/dT metrology at the upcoming ASPE Annual Meeting in Portland, OR. When the final version is published and online, we’ll be sure to update.

Congrats Bill!

Xiangzhi and Chen have papers published

Xiangzhi Yu and Chen Wang both have had first author publications accepted recently. Chen’s paper is Data age error compensation for non-constant velocity metrology, which advances his previous work on data age error to arbitrary orders. This paper has been accepted into IEEE Transactions on Instrumentation and Measurement. More details will be posted when available.

Xiangzhi had two 1st author papers published. His first is with Dr. Tieli Zhang, a former visiting scientist in the group from the Beijing Aerospace Institute for Metrology & Measurement Technology, on Absolute air refractive index measurement and tracking based on variable length vacuum cell. This work was supported by NIST and the paper was published in Optical Engineering.  Xiangzhi’s second paper was with co-authors Dr. Steven Gillmer (now at MIT Lincoln Labs) and Dr. Shane Woody (InSituTec, Inc.) and was published in Review of Scientific Instruments. This work was on the Development of a compact, fi€ber-coupled, six degree-of-freedom measurement system for precision linear stage metrology with research support from NIST and NSF.

Congratulations to both students and the rest of their team! Well done!

Mike Ricci successfully defends his MS Thesis

Mechanical Engineering MS student Mike Ricci successfully defended his MS Thesis. His work, Opto-Mechanical Design of a Three-Degree-of-Freedom Homodyne Interferometer for Freeform Optics Metrology, was part of research within the Center for Freeform Optics. His thesis, once finalized, will be available for viewing under the downloads section.

Mike is now off to Quartus Engineering to work on opto-mechanical design for the aerospace industry. Congratulations Mike and we wish you all the best!

Steve Gillmer successfully defends his PhD research!

Steve Gillmer successfully defended his PhD Thesis, Resolution and Functionality Enhancements in Optical Metrology, this past semester. Steve has worked hard over the past few years and has broadened his expertise to metrology, instrumentation, signal processing, and controls. Steve’s thesis can be accessed on the Downloads page. Steve is off to MIT Lincoln Laboratory and we wish him all the best.

Sam Butler defends MS Thesis Today!

Mechanical Engineering MS student, Sam Butler, will defend his MS thesis work on Thursday, April 14th at 3 PM in the Hopeman 224 conference room.

Development of Electronics and Signal Processing for a Displacement Measuring Interferometer Probe for Freeform Optics

The burgeoning field of freeform optical design is currently limited by metrological techniques for validating manufactured designs. State-of-the-art measurement systems do not provide the flexibility, measurement bandwidth, or low measurement uncertainty required for producing freeform optics of the same quality achievable for spherical and aspheric parts. One promising avenue for reaching high-quality metrology is through the use of optical coordinate measuring machines (OCMM). These are 5-axis probing machines that use non-contact, optics-based probes for surface measurement. This research seeks to develop an optical probe with high measurement bandwidth and low measurement uncertainty in a compact form factor that provides linear and angular measurement of the optical surface under test. The probe uses homodyne interferometry in a Michelson configuration for linear displacement sensing, and a lens in combination with a position-sensitive detector in an autocollimation capacity for angular displacement sensing. Development of electronics and signal processing, as well as preliminary measurement results using a prototype probe, will be discussed.

Paper accepted in Precision Engineering

Jonathan Ellis, along with researchers at the University of South Carolina and the University of North Carolina at Charlotte have recently had a paper accepted in Precision Engineering. The paper entitled, “Application of the continuous wavelet transform in periodic error compensation,” demonstrates a novel algorithm for the compensation of periodic error for both constant and non-constant velocity motion. Congratulations to first author Chao Lu, a MechE PhD student under Prof. Joshua A. Tarbutton at the University of South Carolina, for his first 1st author journal publication!

The prepress of the paper can be accessed here.

Xiangzhi Defends Thesis Proposal Today

Xiangzhi Yu, mechanical engineering PhD student, is defending his PhD Thesis Proposal today, Monday, December 14 at 1 PM. The location for his Proposal Defense is in Hopeman 224.

Precision linear stages provide the basic movement for many nanotechnology systems such as lithography stages, biological scanning systems, and nanofabrication positioning systems. All these systems require precise position sensing for feedback control and extensive calibration procedures to achieve the required accuracy. In this proposal, a compact state-of-the-art multidegree of freedom optical metrology system is presented which will enable fast, accurate calibration and error mapping of multiple axes simultaneously. The working principle for each degree-of-freedom measurement is shown and system-level integration will be investigated to evaluate the overall performance. In addition, the proposed system will significantly mitigate the temporal, dynamic, location and Abbe errors during calibration process. In the end, a refractometer which enables both absolute refractive index of air sensing and tracking based on variable length vacuum cell is presented, which is essential for ultra-precision interferometry measurements under atmospheric conditions.

MST Paper by Xiangzhi & Steve published

Research by MechE PhD students Xiangzhi Yu and Steven Gillmer has been published by Measurement Science & Technology. Their work, Beam geometry, alignment, and wavefront aberration effects on interferometric differential wavefront sensing, shows how including these effects in DWS can enable calibration level measurements for linear stages. More information on the article can be found here.

Sam & Mike awarded 1st Place at OptiFab 2015

Congratulations to Sam Butler and Mike Ricci, MS students in the Department of Mechanical Engineering, for presenting their work at the 2015 SPIE OptiFab conference in Rochester, NY. Their work with co-authors Chen Wang (UR-ECE) and Dr. Qun Wei (CIOMP and UR-Optics) entitled Homodyne displacement measuring interferometer probe for optical coordinate measuring machine with tip and tilt sensitivity was awarded 1st prize in the APOMA Outstanding Student Poster Competition, sponsored by the American Precision Optics Manufacturers Association (APOMA). More information on the award can be found here and their paper can be found here.