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Keywords: non-linear optics, quasi phase matching, second harmonic generation, periodically poled lithium niobate, e-beam.

Summary

Our paper introduces the main principles of nonlinear optical methods like frequency conversion, second harmonic generation, sum- and difference frequency generation and optical parametric oscillation. These methods require an effective phase matching of the pumping and generated electromagnetic fields [1]

Crystals with periodically modified domain structure are called periodically polarised crystals, in our case periodically poled lithium-niobate (PPLN). There are several methods to produce PPLN: one of these is the electron beam bombardment. This article introduces some results of a research project where the aim is to develop a device which is able to create a patterned surface charge density on ferroelectric crystals. The paper introduces how the surface charge pattern was generated with the help of the electron beam of a scanning electron microscope where the electron beam deflection is controlled by a microcontroller to produce the necessary surface charge pattern.

We have determined the parameters of the scanning electron microscope (accelerating voltage, charge density, etc.) and also we have examined the pattern considering the effects happen in the crystal (damage caused by the electron bombardement, influence of surface conduction, contrast of the illuminated pattern, etc.)

Our goal is to create a method adapted for changing the wavelength of the light sources and to develop a device that is able to create a patterned surface charge density distribution on ferroelectric crystals to produce controlled domain structure ready for light frequency conversion.

We have worked out a procedure to determine the parameters of the PPLN structures. We have determined the physical conditions of periodic polarisation using the electron beam and improving the control of the e-beam polarisation.

Works are carried out to revise the contrast of the illuminated pattern, the role of doping (MgO) materials and solving the insulation problems with resists.

References

1: C. Restoin, S. Massy, C. Darraud-Taupiac, A. Barthelemy, "Fabrication of 1D and 2D structures at submicrometer scale on lithium niobate by electron beam bombardment", Optical Materials 22, 193-199, 2003. doi:10.1016/S0925-3467(02)00244-6

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 89 PROCEEDINGS OF THE SIXTH INTERNATIONAL CONFERENCE ON ENGINEERING COMPUTATIONAL TECHNOLOGY Edited by: M. Papadrakakis and B.H.V. Topping Paper 122 Creation of Periodically Poled Lithium Niobate by Domain Structure Inversion with a Scanning Electron Microscope A. Nagyváradi¹ and G. Almási² ¹Pollack Mihály Faculty of Engineering, ²Institute of Physics, University of Pécs, Hungary doi:10.4203/ccp.89.122 purchase the full-text of this paper Full Bibliographic Reference for this paper , "Creation of Periodically Poled Lithium Niobate by Domain Structure Inversion with a Scanning Electron Microscope", in M. Papadrakakis, B.H.V. Topping, (Editors), "Proceedings of the Sixth International Conference on Engineering Computational Technology", Civil-Comp Press, Stirlingshire, UK, Paper 122, 2008. doi:10.4203/ccp.89.122 Keywords: non-linear optics, quasi phase matching, second harmonic generation, periodically poled lithium niobate, e-beam. Summary Our paper introduces the main principles of nonlinear optical methods like frequency conversion, second harmonic generation, sum- and difference frequency generation and optical parametric oscillation. These methods require an effective phase matching of the pumping and generated electromagnetic fields [1] Crystals with periodically modified domain structure are called periodically polarised crystals, in our case periodically poled lithium-niobate (PPLN). There are several methods to produce PPLN: one of these is the electron beam bombardment. This article introduces some results of a research project where the aim is to develop a device which is able to create a patterned surface charge density on ferroelectric crystals. The paper introduces how the surface charge pattern was generated with the help of the electron beam of a scanning electron microscope where the electron beam deflection is controlled by a microcontroller to produce the necessary surface charge pattern. We have determined the parameters of the scanning electron microscope (accelerating voltage, charge density, etc.) and also we have examined the pattern considering the effects happen in the crystal (damage caused by the electron bombardement, influence of surface conduction, contrast of the illuminated pattern, etc.) Our goal is to create a method adapted for changing the wavelength of the light sources and to develop a device that is able to create a patterned surface charge density distribution on ferroelectric crystals to produce controlled domain structure ready for light frequency conversion. We have worked out a procedure to determine the parameters of the PPLN structures. We have determined the physical conditions of periodic polarisation using the electron beam and improving the control of the e-beam polarisation. Works are carried out to revise the contrast of the illuminated pattern, the role of doping (MgO) materials and solving the insulation problems with resists. References 1 C. Restoin, S. Massy, C. Darraud-Taupiac, A. Barthelemy, "Fabrication of 1D and 2D structures at submicrometer scale on lithium niobate by electron beam bombardment", Optical Materials 22, 193-199, 2003. doi:10.1016/S0925-3467(02)00244-6 purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £95 +P&P)
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