Two PhD students, Kaitlin Wozniak (Optics) and Michael Echter ( Mechanical Engineering), have successfully defended their PhD proposals, outlining the scopes of their respective research to finalize their degrees. Kaitlin’s proposed work is on Properties and Safety of Femtosecond Photo-modification in Hydrogel and Cornea as part of the IRIS: Intra-tissue Refractive Index Shaping program at the University of Rochester. Mike’s work is on Composite Laminate Characterization and Piezoelectric Actuator Testing for
the Design of a Precision, Adaptive, High-Strain Composite Hinge, working with the MIT Lincoln Laboratory. Congratulations to both!
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.