Dissertation > Excellent graduate degree dissertation topics show

Mg Effect on Spectroscopic Properties of Er:LiNbO3

Author: YangQingZhong
Tutor: ZhangDeLong
School: Tianjin University
Course: Optical Engineering
Keywords: LiNbO3 crystal J-O theory Absorption spectrum Spectrum parameter Defect structure model
CLC: O433.4
Type: Master's thesis
Year: 2009
Downloads: 19
Quote: 0
Read: Download Dissertation

Abstract


Lithium niobate (LiNbO3) has become a most common crystal material to fabricate waveguide for its physical properties. Many important properties strongly depend on the composition and lattice defects inside the Lithium niobate crystal. Deep MgO doped Er:LiNbO3 can enhance 1.5um emission and suppress green upconversion emission. Since the waveguide amplifier and laser at 1.54μm is commonly concerned and studied,it is greatly necessary to study the effects and mechanism of action about deep Mg-doping to Er:LiNbO3. Some experimental results are reached in this article.These experimental can offer considerable guidance to further work in the future.The main work of the dissertation can be summarized as following three aspects:1. At room temperature Y cut Er (1 mol%):LiNbO3 unpolarized absorption spectrum with several MgO-codoped concentration (2,4,6,8 mol%) were measured, and an obvious blue shift of Mg doped LiNbO3 optical absorption edge was observed.With the growth of Mg concentration, integral quantities of absorption coefficient in absorption band decrease which shows Mg doping restrains the absorption of each energy level. The unpolarized absorption spectrum was analyzed with J-O theory, Experimental and theoretical value of Er3+ electronics transition intension is obtained at different Mg concentration doped respectively.2.By using a 800nm femtosecond laser excitation source ,time-resolved spectroscopy study shows that the decay trace of the green upconversion emiission of the Er/Mg codoped crystal is obvious nonexponential and threshold effect.these spectroscopic charachacteristics are associated with the higher concentration of the cluster sites of Er3+ ion,the higher nonradiative cross relaxation.And hence the populations of the lower located manifolds of the Er ion,such as the 4I13/2 (1.5um) manifold resulting in enhancing 1.5um emission and simultaneously suppressing green upconversion emission.3 .The impacts of doping Mg on the microcosmic defect structure of MgO-doped LiNbO3 crystal have been investigated. The existing Mg-doping models have been analyzed and compared, based on which we introduce some improvements. According to the improved model and experimental data, we deduce that the number of the clustered Er ions is related to the population of Li-site vacancy in the crystal: doping Mg decreases the population of Li-site vacancy , which results in the increase of the population of the clustered sites and the enhancement of cross relaxation of the nonradiative transition, and also results in that the nonexponential character of the attenuation curve strengthens and the attenuation life decreases. In order to approve above conclusion, we also design two validation experiments.

Related Dissertations

  1. Research on Dam-Break Probability Analysis Method for Dangerous Reservoir,TV697
  2. Study on Design of Museum Architecture on the Catalytic Theroy,TU242.5
  3. Research on Testing and Analyzing Technology for Time Parameter of Aerospace Relay,TM58
  4. Application of Interior-Point Theory for Reactive Power Optimization in Large Power Systems,TM714.3
  5. Teaching research and practice of high school function,G633.6
  6. Research on Joint Target Detection for Dual-Sensor Image and System Implementation,TP391.41
  7. On Explanatory Power of Conceptual Integration Theory for the Ttanslation of Chinese Ancient Classic Through the Analysis of the English Versions of Tao Te Ching,H315.9
  8. Theory and Practice of Writing Workshop,G633.3
  9. General Secondary Schools Student Political Theory of Teaching Effectiveness,G651
  10. On Civilian-run Colleges and Universities Issue and Its Internal Management System to Improve,G647
  11. Clinical observation of gout Treatment of acute gouty arthritis ( heat Accumulation card),R259
  12. Explore the Role of Reciting to Improve the Rural Junior Middle School Students’ English Listening Ability,G633.41
  13. Research on Characteristics and Relations of Theory of Mind, Attachment to Grandparents and Peer Acceptance among Children Aged 3-5 with Skip-generation Raising,B844.1
  14. Application of Ascending-Descending Theory in Treatment of Chronic Renal Failure,R277.5
  15. Ryle’s Behaviorism,B089
  16. Research on the Board of Trustees Governance Stucture of Chinese Private Colleges Based on the Stakeholder Theory,G648.7
  17. Research on the Theory of the Transmission-line Metamaterials and Their Applications,O441.6
  18. Of wildlife resources and property rights system research,D923.2
  19. Adorno and Modernism,B83-0
  20. On Mao Zedong 's socialist construction idea of ??the creative contribution,A841
  21. Of China's socialist development of the concept of evolution in the way of thinking change,D61

CLC: > Mathematical sciences and chemical > Physics > Optics > Spectroscopy > Spectroscopy
© 2012 www.DissertationTopic.Net  Mobile