Growth of Optical Quality Lead Magnesium Niobate-Lead Titanate Thick Films

Date of Award


Degree Name

M.S. in Electro-Optics


Department of Electro-Optics


Advisor: Paul McManamon


Lead magnesium niobate-lead titanate (1-x)[Pb(Mg1/3Nb2/3)O3]-x[PbTiO3] (PMN-PT) is a relaxor ferroelectric crystal that has many uses, specifically in non-mechanical beam steering for use in Light Detection And Ranging (LIDAR) assemblies, or other optical devices, such as free space laser communication. When using bulk PMN-PT crystals, the voltage required to steer a beam can be in the kilovolt range. However, with unique designs, optical quality PMN-PT polycrystalline thick films (5-50?m thick) could be used in order to minimize the voltage required for beam steering projects to less than 100V. Steering an optical beam requires a change in index of refraction, which is dependent on the electric field. The required voltage to produce an electric field is dependent on the thickness of the field region, so thinner regions between electrodes will result in lower required voltage to produce the same electric field, and therefore the same change in index of refraction. In the present research, PMN-PT polycrystalline thick films were grown on strontium titanate (SrTiO3), lanthanum aluminate (LaAlO3), and platinum substrates, via a modified sol-gel method. These films were deposited by a dip-coat method and annealed by a fast-fire method. Using the polycrystalline PMN-PT crystal as a phase modulator, the optical path delay (OPD) was measured with a maximum voltage applied across the PMN-PT crystal. Using Jones matrices to calculate the polarization and crystallography to identify the correct electro-optical coefficients, we can measure the values for a few specific linear electro-optic coefficients. This experiment resulted in a measured value for the linear electro-optic effect coefficient, ?13, of 196pm/V while only applying 23V across the crystal.


Physics, Optics, Materials Science, PMNPT, PMN-PT, optical crystal, thick film, thin films, electro optic, electro-optic, kerr effect, pockels effect, polycrystalline, ceramic crystal, relaxor, ferroelectric, laser, communication, sol-gel, dip coat, beam steering

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