College of Engineering at UMass Dartmouth

Examinations begin today.

UMass Dartmouth

Spring 2024 Second 7-week session final exam day.

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Mechanical Engineering MS Project Presentation by Mr. Noah Whitney DATE: May 3, 2024 TIME: 3:00 P.M. - 5:00 P.M. LOCATION: Zoom link: https://umassd.zoom.us/j/93989772725?pwd=Ulk5ME9KYnpvMGhBU2toZ1dKeHE3dz09 (Contact scunha@umassd.edu for Meeting ID# and Passcode) TOPIC: Ion Beam Figuring Prototype for Guiding the Polishing Process of Optical Substrates ABSTRACT: For high efficiency optical components, substrate surface smoothness is critical. This project aims to create a polishing method for substrates that can be performed at Plymouth Grating Laboratory, for the purpose of creating ultra-high efficiency diffraction gratings. Traditional polishing methods, such as pitch polishing and lap polishing, use an abrasive slurry to mechanically smooth substrate surfaces. This method can be quite expensive and often fails for large scale optics. Therefore, a non-mechanical polishing technique called Ion Beam Figuring is proposed as an alternative method for substrate polishing. This method can be achieved on site at Plymouth Grating Laboratory while simultaneously reducing cost and increasing the likelihood of a successful polish. To achieve this method of polishing, a framework is developed for experimentally profiling a radio frequency ion source, via broadband spectroscopy. Next, a prototype 1-dimensional Ion Beam Figuring method is created using a custom MATLAB program. This program yields a dwell time map, which guides the figuring process by determining the position and time for which the ion beam etches the substrate. This prototype Ion Beam Figuring program will be based on a Fourier transform deconvolution method. Once this program was created, initial validations were performed using test case surface profiles to ensure the program properly computes parameters used in the IBF process. This project provides a foundation to produce large polished substrates with higher reliability and a significantly decreased cost. This is a key step in creating high efficiency meter class diffraction gratings to be used in some of the highest power laser systems in the world. These laser systems can be used in fusion, biomedical, defense, and semiconductor industries. ADVISOR: - Dr. Jun Li, Assistant Professor, Department of Mechanical Engineering, UMass Dartmouth COMMITTEE MEMBERS: - Dr. Wenzhen Huang, Professor, Department of Mechanical Engineering, UMass Dartmouth - Dr. Alfa Heryudono, Associate Professor, Department of Mathematics, UMass Dartmouth Open to the public. All MNE students are encouraged to attend. For more information, please contact Dr. Jun Li (jun.li@umassd.edu).

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Spring 2024 Second 7-week session grades are due, 72 hours from final exam day.

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Spring 2024 Final Exams end for the Third 5-week session MLT-MLS Program classes.

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Spring 2024 14-week full session final exams end.

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