The design of anti-reflective coatings for a quantum cascade laser emitting light in the mid-infrared range

dc.contributor.advisorCrawford, Richard H.
dc.contributor.advisorBelkin, Mikhail A.
dc.creatorBennett, Agatha Karenen
dc.date.accessioned2013-12-10T22:21:30Zen
dc.date.accessioned2017-05-11T22:40:02Z
dc.date.available2017-05-11T22:40:02Z
dc.date.issued2013-08en
dc.date.submittedAugust 2013en
dc.date.updated2013-12-10T22:21:30Zen
dc.descriptiontexten
dc.description.abstractQuantum cascade lasers (QCL) are semiconductor lasers that emit radiation in the mid-infrared to the terahertz (THz) range. External cavity quantum cascade lasers are broadly tunable mid-infrared and even THz laser sources that have a wide variety of applications in spectroscopy, sensing, imaging and other areas. Anti-reflection (AR) coatings, when applied on the laser facet reduce parasitic lasing, increase spectrum purity and tuning range, are crucial for good performance of external cavity systems. This report describes the process of determining the thickness of a double layer AR coating, applying the coatings to a quantum cascade laser and testing its reflectivity in the mid-infrared range. We determined the thickness of each layer of the AR coatings by building a propagation matrix model using Mathematica. We applied the coatings of Al2O3 and ZnSe using an Electron Beam Physical Vapor Deposition and a Sputtering Deposition system. Finally we tested the reflectivity of the laser by measuring a change in threshold current. The initial reflectivity of 30% was reduced to 7.7% with the addition of the AR coatings.en
dc.description.departmentScience and Mathematics Educationen
dc.format.mimetypeapplication/pdfen
dc.identifier.urihttp://hdl.handle.net/2152/22627en
dc.language.isoen_USen
dc.subjectAnti-reflectionen
dc.titleThe design of anti-reflective coatings for a quantum cascade laser emitting light in the mid-infrared rangeen

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