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Estudos opticos dos centros de cor em cristais LiYF4:Nd3+MACEDO, TANIA C.A. 09 October 2014 (has links)
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01411.pdf: 1427457 bytes, checksum: 9115b3894c3a648de77a8f438360c26c (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Operacao C.W. e sintonia por um par de prismas de um laser de cor KCL:TLsup0 (1)PEIRO, GREGORIO P. 09 October 2014 (has links)
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02195.pdf: 1757480 bytes, checksum: 739dc260b2486dfe469bf77fa1698a31 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Fisica, Universidade de Sao Paulo - IF/USP
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Estudos opticos dos centros de cor em cristais LiYF4:Nd3+MACEDO, TANIA C.A. 09 October 2014 (has links)
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01411.pdf: 1427457 bytes, checksum: 9115b3894c3a648de77a8f438360c26c (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Operacao C.W. e sintonia por um par de prismas de um laser de cor KCL:TLsup0 (1)PEIRO, GREGORIO P. 09 October 2014 (has links)
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02195.pdf: 1757480 bytes, checksum: 739dc260b2486dfe469bf77fa1698a31 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Fisica, Universidade de Sao Paulo - IF/USP
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Operacao do laser KCl:Tlsup(0)(1) no regime de travamento de modos por bombeamento sincronoFREITAS, ANDERSON Z. de 09 October 2014 (has links)
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05240.pdf: 4018365 bytes, checksum: e396b233b17c8c7b02169aa142deba30 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:94/04083-5
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Operacao do laser KCl:Tlsup(0)(1) no regime de travamento de modos por bombeamento sincronoFREITAS, ANDERSON Z. de 09 October 2014 (has links)
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05240.pdf: 4018365 bytes, checksum: e396b233b17c8c7b02169aa142deba30 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:94/04083-5
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The Stark effect of M, N, and Z color centers in alkali halidesDeWerd, Larry Albert, January 1971 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1971. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.
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Ionizing-Radiation-Induced Color Centers in YAG, Nd:YAG, and Cr:Nd:YAG: Developing and Analyzing a Radiation-Hard Laser Gain MediumGlebov, Boris L. January 2010 (has links)
This report presents results from a series of experiments in which YAG samples (undoped, as well as doped with Nd and Cr3+) were exposed to ionizing radiation (gamma rays and UV). These experiments were performed for the purpose of investigating the various phtodarkening processes taking place in these materials in response to the ionizing radiation. The purpose of this investigation was to establish whether and how co-doping YAG with Cr3+ improves the material's resistance to photodarkening due to the ionizing radiation. The experiments tracked time-resolved transmittance of the samples at 1064 nm in immediate response a pulsed exposure to the ionizing radiation, as well as steady-state spectrally-resolved changed in the samples' optical absorption after the irradiation. The investigation revealed a number of photodarkening processes occurring in the samples in response to the ionizing radiation, both transient and permanent. It was further revealed that inclusion of Cr3+ ions in YAG significantly reduces these photodarkening processes, improving the material's radiation resistance. It was observed that materials containing at least 0.5 at% Cr3+ are essentially radiation-hardened, resisting both transient and steady-state changes in transmittance observed in the materials not containing Cr3+.
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Medidas de transições ópticas em candidatos a meio laser ativo: aplicação a centros de cor / Measurements of optical transitions in candidates for active laser medium: application to color centersMartins, Evely 20 April 1990 (has links)
Centros de cor e íons de metal de transição em cristais iônicos tem mostrado um grande potencial como candidatos a meios laser ativos sintonizáveis. Para determinar se tais materiais são apropriados ou não para operar como meios laser, seus parâmetros espectroscópicos fundamentais tem de ser conhecidos. No presente trabalho, nos descrevemos um metodo espectroscópico que permite determinar o diagrama de níveis de energia da espécie investigada, o tempo de decaimento, a eficiência quântica e a secção de choque de emissão. O tempo de decaimento foi medido usando-se um bombeamento senoidal de excitação e detecção sensível a fase; obtendo-se 1,6ms para o kcl:TL POT.0 (1), 17ns para o LIf:F IND.2, 28ns para o LIf:F2 POT.+ E 4ns para o LIf:F3 POT.+. Usando-se uma técnica de absorção rotulada foi possível determinar absorções do estado fundamental e do primeiro estado excitado da espécie investigada mesmo com a interferência de outros centros. Técnica utilizada em kcl:tl onde níveis de energia do centro de cor de TL POT.0 (1) foram identificados vários outros agregados de tl devido a preparação do cristal, que perturbam o centro TL POT.0 (1) também foram identificados. Vários outros agregados de T1, devido a preparação do cristal, que perturbam o centro TL POT.0 (1), também foram observados. / Color centers and transition metal ions in ionic crystals have shown a qreat potential as candidates for tunable laser sources. In order to determine whether or not such materials are suitable to operate as laser media, their fundamental spectroscopic parameters have to be known. In the present work we describe a spectroscopic method that can determine the energy level diagram of the species under investigation, the decay time, quantum efficiency and emission cross section. Firstly, the decay time was measured by using a sinosoidal pumping excitation and phase sensitive detection. Using a specially home designed cryostat we were able to measure the decay time in the temperature range of 77K to 310K, and therefore, the temperature dependence of the quantum efficiency. This technique was applied to the T1°(1):KCl, F2:LiF, F+3:LiF and F+2:LiF, where decay times of 1.6s, 17ns, 4ns and 28ns were measure, respectively. Secondly, by using a pump-probe technique we were able to determine the excited-state absorption of the studied species, even under the interference of other centers. This is particularly important in color centers due to the presence of several other species during the centers formation. Besides, this technique can identify excited state absorptions that can eliminate laser medium candidates. This technique was used in KCl:T1 crystals where laser active Tl° (1) color center energy levels were identified. Besides, several other Tl aggregates due to the crystal preparation that perturb the Tl° (1) center were also observed.
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Criação e caracterização óptica em cristais de KI / Growth and optical characterizations of color centers in KIAndrade, Luis Humberto da Cunha 22 April 1999 (has links)
No presente trabalho apresentamos um outro método para criação de centros de cor, em matrizes de KI puro, através da absorção de dois fótons. Este processo possui uma característica útil: a coloração é realizada a baixa temperatura, ao contrário de outros métodos, que necessitam aquecer o cristal até próximo a ponto de fusão, fazendo com que as impurezas adicionadas durante o crescimento migrem para a superfície do cristal. Com este método, colorimos alguns cristais de KI puro, a fim de demonstrar a eficiência do processo, e algumas aplicações deste como em cristais de KI: \'Cu POT.+\', onde foi realizada a tentativa de criação de centros de cor do tipo \'F IND.A\', e cristais de KI:\'Yb POT.2+\', nos quais foram identificados centros de cor do tipo Z, com a possibilidade de formação de novos centros. Outras propriedades interessantes, como a suposta formação de \'Yb POT.3+\' nessas matrizes a partir da criação de centros de cor, abrem espaço para mais um amplo estudo desse processo, que ainda deverá ser investigado. / In this work we present an other method to produce color centers in pure KI lattice by two photon absorption. This process has a useful feature: coloring is achieved at low temperature as opposed to other methods that require heating of crystal up to near fusion temperature in such a way that impurities added during growing migrate to the surface of crystal. By this method we colored some pure KI crystals to demonstrate the efficiency and some applications of the process to some crystals such as KI: \'Cu POT.+\' crystals trying to create FA centers and KI:\'Yb POT.2+\' crystals where we identified Z centers with possibilities of formation of other centers. Other interesting properties as the supposed formation of \'Yb POT.3+\' in these lattices through color center creation widen the study of the process to be yet investigated.
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