Xiangzhi Yu, Mechanical Engineering PhD student, has successfully defended his PhD work entitled Multi-Degree of Freedom Optical Metrology Techniques. Xiangzhi is the second student graduate with his PhD from the group. After graduation, Xiangzhi will head to FARO where he has accepted a position as a Senior Systems Engineer. Congratulations and good luck on the next step in your career!
Undergraduate student Bill Green from Mechanical Engineering recently presented his work on Gradient Index (GRIN) Metrology at the 31st Annual ASPE Meeting. His work, entitled Development of a Twyman-Green Interferometer Capable of Measuring the Thermal Properties of Optical Materials, was presented on behalf of co-authors James Corsetti, Greg Schmidt, Duncan Moore, and Jonathan Ellis. It is a pretty rare feat for an undergraduate student to be selected to present at a major international conference. Well done Bill!
Professor Ellis recently gave an invited talk at the Frontiers in Optics conference held in Rochester, NY this past October. The subject of his talk, IRIS – A new paradigm in laser refractive correction, was an overview of how femtosecond lasers and multi-photon absorption can induce meaningful refractive change in cornea and hydrogels. This work, with co-authors Gustavo Gandara, Dan Brooks, Kaitlin Wozniak, Sara Gearhart, Len Zheleznyak, Paul Funkenbusch, Wayne Knox, and Krystel Huxlin, is part of a larger research program centered on non-invasive vision correction.
In addition to that talk, Professor Ellis was not the only person in the family participating in OSA’s 100 year celebration. Julia Ellis, his daughter, was selected to hand out awards to the panel of seven Nobel Laureates.
Ethan Burnham-Fay, Xiangzhi Yu, Fenghe Zhong, and Allie Browar placed second in the 3rd Annual ASPE Student Competition held in Portland, Oregon in late October this fall. The group spent all night working on a laser scanning system using MechBlocks from MOTUS Mechanical.
Also, these four students, along with Chen Wang, Dan Brooks, Kaitlin Wozniak, and Bill Green were all recipients of NSF Grantee Scholarships to attend the ASPE Annual Meeting.
Xiangzhi Yu, PhD student in Mechanical Engineering, will defend his dissertation work Wednesday, November 11 at 9:30 AM (today!!!). His PhD work is on Multi-Degree of Freedom Optical Metrology Techniques. We wish Xiangzhi well during his presentation and defense.
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.
Steven Gillmer, MechE PhD Student, will be defending his PhD work on Tuesday, April 26th at 10:00 AM. The defense will take place in Hopeman 224, in the MechE Conference Room.
Resolution and Functionality Enhancements in Optical Metrology
Scientific experiments continue to push engineering limits beyond the nano-scale, driving the development of extremely high resolution measurement tools and calibrations as a result. The effective implementation of optical metrology and its associated instrumentation involves a multi-disciplinary approach. This thesis draws from mechanical, electrical, and optical engineering subject areas in order to implement the proposed resolution and functionality enhancements. The discussion will focus on three forms of optical metrology: optical displacement sensing, scatterometry, and interferometric weak measurements. The primary applications of the advancements in optical displacement sensing lie in the measurement and calibration of computer numerical control (CNC) equipment and coordinate measuring machines (CMMs). A novel scatterometry tool will be presented for critical-dimension metrology in the continued sustenance of Moore’s law. Finally, optical displacement sensing and scatterometry will find parallels through weak measurements. Both application areas have potential for vast performance improvements via the measurement of a weak value. A variety of novel concepts and experiments will be presented within these fields of research with the ultimate goal of their dissemination into the manufacturing and semiconductor industries.
Sam Butler successfully defended his MS Thesis, Development of Electronics and Signal Processing for a Displacement Measuring Interferometer Probe for Freeform Optics, on April 14th. Sam’s committee consisted of his advisor, Professor Paul Funkenbusch (MechE), and Professor Qiang Lin (ECE).
Sam has recently accepted a position as a System Engineer at Clerio Vision, Inc., a startup company spun off from the University of Rochester and the labs of Prof. Ellis, Knox, and Huxlin. We wish Sam congratulations and all the best in the future!
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.
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.