Bidirectional Reflectance Measurements of Low-Reflectivity Optical Coating Z302

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dc.contributor.authorShirsekar, Deepalien
dc.contributor.committeechairMahan, James Roberten
dc.contributor.committeechairNguyen, Vinhen
dc.contributor.committeememberVick, Brian L.en
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2019-02-06T09:00:29Zen
dc.date.available2019-02-06T09:00:29Zen
dc.date.issued2019-02-05en
dc.description.abstractBlack coatings essentially absorb incident light at all wavelengths from all directions. They are used when minimal reflection or maximum absorption is desired and therefore are effective in applications that require control of stray light. Our motivation stems from the use of black coating Lord AeroglazeĀ® Z302 in aerospace and remote sensing applications and the desire to support the development of bidirectional spectral models that can be used successfully to predict the performance of optical instruments such as telescopes. The bidirectional reflectance distribution function (BRDF) is an indispensable parameter in the optical characterization of such coatings. The current effort involves investigation of the BRDF of the commercial black coating AeroglazeĀ® Z302. An automated goniometer reflectometer has been designed, fabricated and successfully used for performing the BRDF measurements of Z302 at visible and ultraviolet wavelengths and at both polarizations. The current contribution involves study of Z302 samples prepared at different thicknesses and by different methods, which provides insight about influence of surface roughness on BRDF of Z302.en
dc.description.abstractgeneralWhen light falls on different materials it undergoes various phenomenon such as reflection, refraction, absorption and scattering. The amount of each phenomenon varies with the optical nature of a material as well as the wavelength and direction of the light. Therefore, understanding the optical properties of materials at various wavelengths of light is necessary for effectively using those materialsin specific applications which require light to be efficiently reflected or absorbed. This research studies an optical property known as Bidirectional Reflectance Distribution Function (BRDF) of a black coating called Lord Aeroglaze Z302. Black coatings are materials that ideally absorb almost all light that falls on them irrespective of the lightā€™s direction and wavelength. They are used in applications where maximum absorption of light is required. One such application which relates to the motivation for this research is absorbing unwanted light in instruments used in space such as telescopes and radiometers. Z302 is used in the Clouds and the Earthā€™s Radiant Energy System (CERES) instruments developed by NASA. BRDF is an important parameter which gives information about all other optical properties of a surface and can be used to know optical performance of that surface. The current work describes the experiments and an automated device developed, called reflectometer, to measure the BRDF of Z302 at different angles and wavelengths of light. The results are reported for different thickness samples of Z302 coating, and two different wavelengths of light that belong to the visible and ultraviolet spectrum of light.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:18579en
dc.identifier.urihttp://hdl.handle.net/10919/87467en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectBRDFen
dc.subjectBidirectional Reflectivityen
dc.subjectRadiation Heat Transferen
dc.subjectZ302en
dc.subjectMonte-Carlo ray trace methoden
dc.subjectReflectometryen
dc.titleBidirectional Reflectance Measurements of Low-Reflectivity Optical Coating Z302en
dc.typeThesisen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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