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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Study on the Growth and Optical Properties of Large-Sized Highly-Doped Nd:YAG Crystal by Czochralski Technique

Chen, Yingwei 07 August 2012 (has links)
¡@¡@This paper mainly focuses on the discussion about how to grow a large-sized highly-doped laser crystal- Neodymium yttrium aluminum garnet( {NdxY1-x}3Al5O3; Nd:YAG). The higher concentration of Nd:YAG crystal can allow the better efficiency of the laser. Since the ion size doped with Nd3+ ( R= 1.12A ) is larger than the ion size of Y3+ (R= 1.01A ), in the lattice of YAG, it¡¦s not easy to mix the smaller Y3+ site with the larger diameter of the Nd3 + ion. Therefore, the higher concentration of the laser crystal we want to grow, the more difficult work it is. ¡@¡@This experiment works under the use of the Czochralski technique to grow the laser crystal: Nd:YAG, and explore the impacts of different crystal pulling growth conditions on the growth of Nd:YAG crystal. Through adjusting the parameters of crystal growth, the crystal growth environments and the thermal fields, I discuss how to solve the problems of the scattering, cracking and spiral growing during the crystal growth process in order to improve the quality of the crystals. ¡@¡@Finally, comparing the results of a variety of spectral analysis (X-ray diffraction, UV / Vis Spectroscopy, Raman Spectroscopy, PL Spectroscopy) on the slice samples of Nd:YAG crystal which grew by our laboratory with the literature results, we can find that the X-ray diffraction pattern, the absorption spectroscopy, the Raman spectroscopy and the Photoluminescence spectroscopy of the Nd:YAG crystals grew in this experiment are consistent with the literature.
2

Pumping Chamber Design In Diode-pumped Solid-state Lasers For Maximum System Efficiency And Minimum Optical Distortion

Sezgin, Kubilay 01 January 2013 (has links) (PDF)
The beam quality and the system efficiency of a diode-pumped solid-state laser source are directly related to the thermal profile inside the laser crystal. The thermal profile in a laser crystal should be made uniform in order to reduce the negative effects of the thermal lens. However, the absorbed pump profile that forms a uniform thermal profile inside the gain medium may adversely affect the system efficiency. In this thesis, a computational and empirical method was developed for designing pumping chambers that results in a suitable thermal profile inside the gain medium, and thus desired laser beam quality was achieved while keeping the system efficiency at an acceptable level. Accomplishment of this thesis work will lead to the design of pumping chambers and resonators in high power laser systems operating at even higher thermal loads.

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