June 15, 2014
June 15, 2014
June 18, 2014
Engineering Physics & Physics
24.957.1 - 24.957.6
Engineering Physics (EP), at its core, is a multidisciplinary approach to solving problemsthat require insights from various traditional disciplines. The EP curriculum at Rose-HulmanInstitute of Technology strives to foster this multidisciplinary approach by incorporating studentprojects that require integrating concepts and principles from various fields into a meaningfulapproach toward a realistic solution. These projects, ideally involve a design / problemstatement, a fabrication step, and a testing or characterization stage. As an example of such anapproach, a new lab is proposed to provide students with an understanding of optics, thin filmdepositions and real world constraints. Students are presented with the concept of a Fabry-Perot(FP) filter, and are asked to create a metal-dielectric-metal multilayer film to produce filters inthe visible spectrum. The filters are then analyzed with reflectance spectroscopy andellipsometry. The results are then analyzed for consistency and to gain insights into the details ofthe fabrication process and the resulting structure. The project involves fabricating and analyzing a metal-dielectric-metal (MDM) film.MDM is a thin layer of a highly reflective metal (Cr), then a layer of highly transparent dielectricmaterial (SiO2), and finally a thin layer of a highly reflective metal. When light enters an MDMfilm, it can reflect off of the first layer of metal, or it can pass through the metal and dielectric,and reflect off of the second layer of metal. When white light enters an MDM film, it acts muchlike a FP etalon; the light interferes constructively and the reflectance of the film peaks at acertain wavelength. The peak reflectance wavelength, like a Fabry-Perot etalon, is dependent onthe optical path length, e.g., the thickness of the dielectric material, the index of refraction, andthe angle of incidence. By carefully controlling the thickness of the dielectric material, one canchange the reflectance peak of the film. This can be visible to the naked eye, depending upon thethickness of the film, as changing the color of the film. By adding more layers, the width of thereflectance peak can be decreased. Also, as more layers are added, the peak reflectance increases.The fabricated structures are also analyzed by reflectance and spectroscopic ellipsometry tounderstand how the actual sample differs from the ideal structure that is proposed. We alsodiscuss how this project can be incorporated into different classes with varying emphasis.Examples of possible courses that can benefit from such a project include senior project, opticsof materials, Advanced MEMs, etc.
Kirkpatrick, S. R., & Syed, M. M., & Liptak, R. W. (2014, June), Optical Filter Design, Fabrication and Characterization; A Multifaceted Approach to Project- Based Curriculum Paper presented at 2014 ASEE Annual Conference & Exposition, Indianapolis, Indiana. https://peer.asee.org/22890
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