Simulation of thermal, mechanical and optical behavior of yag ceramics with increasing Nd3+ concentration under lasing conditions.

Download
2007
Kenar, Necmettin
Two-dimensional thermal, mechanical and optical simulations are carried out to investigate the effect of Nd3+ concentration on thermal, mechanical and optical behavior of Nd:YAG ceramic laser materials under continuous wave laser operation. In the analyses, rods are pumped longitudinally with laser diodes, in three, six, nine and twelve fold structures. Rods having diameters of 3 and 6 mm are pumped with 808 nm and 885 nm sources separately having Nd+3 concentrations of 0.6, 1, 2, 3, 4 and 6 at. %. Total absorbed pump power are kept constant for all rods. Absorbed pump power distribution are obtained for each rod using ray tracing method and Beer’s Law. In the analysis, temperature dependent material properties are incorporated. Nonlinear numerical solutions of thermal and stress equations have been performed. Temperature and stress results are obtained to investigate the effect of Nd concentration on the optical properties of ceramic YAG laser material. Analysis results reveal that, increase in Nd3+ concentration of YAG ceramic laser material, decreases the temperature and stress developed during optical pumping. Rods pumped with 808 nm source have large temperature and stress values compared to 885 nm pumped ones. Optical path difference (OPD) of each ray passed trough the material is calculated using thermal and elastic strain results together with photo-elastic constants of Nd:YAG material. Focal length and depolarization of each rod is calculated numerically from OPD results. Focal length of each rod is found to increase, in contrary depolarization is found to decrease with increase in the dopant concentration.

Suggestions

Pumping chamber design in diode pumped solid-state lasers for maximum system efficiency and minimum optical distortion
Zengin, Kubilay; Sayan, Gönül; Yelen, Kuthan; Department of Electrical and Electronics Engineering (2013)
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 chamb...
Analysis of reconstruction performance of magnetic resonance conductivity tensor imaging (MRCTI) using simulated measurements
DEĞİRMENCİ, EVREN; Eyüboğlu, Behçet Murat (2017-01-01)
Magnetic resonance conductivity tensor imaging (MRCTI) was proposed recently to produce electrical conductivity images of anisotropic tissues. Similar to magnetic resonance electrical impedance tomography (MREIT), MRCTI uses magnetic field and boundary potential measurements obtained utilizing magnetic resonance imaging techniques. MRCTI reconstructs tensor images of anisotropic conductivity whereas MREIT reconstructs isotropic conductivity images. In this study, spatial resolution and linearity of five rec...
Design and production of antireflection coating for Ge, ZnSe and ZnS in 8-12 micrometer wavelength region
Üçer, Begüm; Parlak, Mehmet; Department of Physics (2009)
This thesis describes the works done during the design and deposition process of the antireflection coating for the materials commonly used as refractive optical elements in thermal imaging systems. These coatings are quite necessary to reduce reflection losses from the surface of the optics and stray light that directly affects the image quality. Germanium, zinc sulfide and zinc selenide were used as substrate material and their optical properties were investigated with infrared ellipsometry and FTIR. Anti...
High temperature chemistry of some borophosphates, phase relations and structural studies
Seyyidoğlu, Semih; Kızılyallı, Meral; Department of Chemistry (2003)
The solid state, hydrothermal and flux methods were used for the investigation of alkaline earth and transition metal borophosphate compounds. The products and the phase relations were investigated by XRD, IR, DTA, and EDX methods. The solid state reactions of several boron compounds with different phosphating agents have been studied in the temperature range of 400-1200 oC. Hydrothermal and flux techniques were performed at 150 oC and 1200 oC, respectively. On the other hand, an attempt has been made to pr...
Simulation of crystallization and glass formation processes for binary Pd-Ag metal alloys
Kart, HH; Uludogan, M; Cagin, T; Tomak, Mehmet (2003-09-12)
Glass formation and crystallization process of Pd-Ag metallic alloys are investigated by means of molecular dynamics simulation. This simulation uses the quantum Sutton-Chen (Q-SC) potential to study structural and transport properties of Pd-Ag alloys. Cooling rates and concentration effects on the glass formation and crystallization of binary alloys considered in this work are investigated. Pd-Ag alloys show the glass structure at fast cooling rates while it crystallizes at slow cooling rates. Increment of...
Citation Formats
N. Kenar, “Simulation of thermal, mechanical and optical behavior of yag ceramics with increasing Nd3+ concentration under lasing conditions.,” Ph.D. - Doctoral Program, Middle East Technical University, 2007.