Optical Properties of Solids Optical materials Non linear optical materials play an important 丽 Laser role in data transmission and storage T Non linear optical properties LiNbO, KTiOPO, KH,PO 重 Photoluminescence T Laser materials semiconductors and laser host crystals e Phosphors for displays and imaging Interactions between photons and materials When Light Meets a Solid ic and Electronic Interactions o Total intensity equals electron cloud induces electronic polarization ● Transmitted nergy lost in absorption .Absorbed slows light down (seen as refraction .Reflected eLectron Transitions-electrons excited to higher unoccupied states QT+A+RE I cannot remain there indefinitely =Emission .(fraction transmitted, absorbed and optical characteristics of a material relate to the sorption and emission of electromagnetic radiation Optical Properties of Semiconductors Classes of Optical Materials otion Materials are often characterized by what happens to ligh atransparent ostly transmitted transmitted diffusely Copaque no transmission 4shiny-mostly reflected a longest wavelength absorption to promote e corresponds to E T Eg is energy between"HOMO"of valence band and LUMO" of conduction band1 Optical Properties of Solids Laser Non-linear optical properties Photoluminescence Optical Materials Non-linear optical materials play an important role in data transmission and storage LiNbO3 , KTiOPO4 , KH2PO4 Laser materials semiconductors and laser host crystals Phosphors for displays and imaging Interactions Between Photons and Materials Atomic and Electronic Interactions Electronic Polarization ¾ interaction with electron cloud induces electronic polarizationÞ energy lost in absorption slows light down (seen as refraction) Electron Transitions ¾ electrons excited to higher unoccupied statesÞ cannot remain there indefinitely ÞEmission optical characteristics of a material relate to the absorption and emission of electromagnetic radiation When Light Meets a Solid… . Total intensity equals: Transmitted Absorbed Reflected T+A+R = 1 (fraction transmitted, absorbed and reflected = 1) Classes of Optical Materials Materials are often characterized by what happens to light transparent ¾¾ mostly transmitted translucent ¾¾ transmitted diffusely opaque ¾¾ no transmission shiny ¾¾ mostly reflected Optical Properties of Semiconductors Absorption Eg longest wavelength absorption to promote e￾corresponds to Eg Eg is energy between “HOMO ”of valence band and “LUMO”of conduction band Emission Eg