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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.
141

Optical and luminescence properties of erbium, ytterbium and terbium doped in aluminum nitride

Corn, Tyler R. 24 July 2010 (has links)
Studies have been done to determine rare-earth elements’ optical and luminescent properties using wide bandgap nitride semiconductors as suitable hosts. Research done here will contribute to the information needed to further study rare-earth elements and their unique properties. Thin films of rare-earth elements erbium, terbium, ytterbium, and both erbium and ytterbium doped into AlN are studied by laser excitation. A 532 nm Nd: YAG green laser and 783nm crystal infrared laser are used for excitation in conjunction with a spectrometer to measure photoluminescence. With the 532 nm laser, AlN: Er emits peaks at 554 nm, 561 nm, and 1552 nm, AlN: Tb emits peaks at 549 nm and 562 nm, AlN: Yb emits peaks at 966 nm, and co-doped AlN: ErYb contains peaks including both AlN: Er and AlN: Yb. Energy transfer occurred from Er to Yb resulting in an increased magnitude and peak shift. The 783 nm laser gave peaks at 1563nm for AlN: Er, 1508 nm and 1533 nm for AlN: Tb, and 1567nm for AlN: ErYb. No detectable peaks were given for AlN: Yb. A peak shift was detected in comparison of AlN: Er and AlN: ErYb. A magnetic field of 1000 G was applied to AlN: ErYb resulting in an increase in intensity of the major peak at 561nm with a splitting, creating a secondary peak at 564.5 nm. Biomedical applications can be used from the high penetration ability of lower wavelength lasers and the use of a magnetic field, which is not harmful to the human body. Enhanced green emission in erbium can be useful in future optical, photonic, and electrical devices. / Department of Physics and Astronomy
142

Développement d'un laser verre codopé erbium et ytterbium compact à sécurité oculaire pour des applications de télémétrie.

Tanguy, Eric 24 September 1996 (has links) (PDF)
Leur grande efficacité et leur directivité font des lasers des sources optiques extrêmement dangereuses pour l' oeil humain. Cependant il existe une bande spectrale s'étendant de 1,5 à 1,55 µm où le seuil d'endommagement de l'oeil est plus élevé et où les risques encourus sont moins importants. Cette bande spectrale est dite à " sécurité oculaire ". Un laser solide pompé par diode laser émettant dans cette bande spectrale doit trouver de nombreuses applications dans les domaines de la détection d' obstacles et de la télémétrie. Ce travail a donc pour objectif d' étudier théoriquement et de valider expérimentalement un tel laser à sécurité oculaire pompé par diode laser de puissance fondé sur l'utilisation d'un verre codopé erbium et ytterbium. Ce laser fonctionne en régime continu et déclenché mécaniquement. En régime continu une puissance de 100 mW avec un faisceau gaussien parfait a été obtenue pour une puissance de pompe absorbée de 650 mW. En régime déclenché par insertion dans la cavité d'un disque tournant, nous avons obtenu une puissance crête de 120W sur une impulsion de 35 ns de largeur à mi-hauteur et en régime déclenché par insertion d'un diapason dans la cavité, nous avons obtenu une puissance crête de 50 W sur une impulsion de 60 ns de largeur à mi-hauteur. Les résultats intéressants obtenus en régime déclenché nous ont permis de réaliser un télémètre à sécurité oculaire.
143

Entwicklung und Untersuchungen zur Herstellung verlustarmer passiver Wellenleiter und verstärkender Wellenleiter

Graf, Jürgen. Unknown Date (has links) (PDF)
Universiẗat, Diss., 1999--Saarbrücken. / Erscheinungsjahr auf der Haupttitels.: 1999.
144

Avaliação da adesão de fibroblastos sobre superfícies apicectomizadas pelo laser de Er:YAG e tratadas ou não com o laser de Nd:YAG

LOBATO NETO, ARCELINO de M. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:51:25Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:01Z (GMT). No. of bitstreams: 1 11302.pdf: 6104294 bytes, checksum: 2f6603857241226128098a3cdc3f54ff (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo
145

Avaliacao da temperatura na camara pulpar durante preparo classe V com laser de erbio:YAG

PICININI, LEONARDO S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:46:37Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:34Z (GMT). No. of bitstreams: 1 08352.pdf: 3349850 bytes, checksum: 8bcc73d5ede4b0438ca9f74691cebab8 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo
146

Avaliacao da temperatura intrapulpar de incisivos bovinos irradiados com o laser de ER:YAG

MARTINS, VINICIUS R.G. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:48:12Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:01Z (GMT). No. of bitstreams: 1 09325.pdf: 3741931 bytes, checksum: 56ca1474041429eb96c795e1072d01c0 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo
147

Avaliacao da dor e da reparacao clinica em pacientes submetidos a frenectomia com lasers de diodo(808nm) ou Er, Cr:YSGG ou por tecnica convencional

TREVISAN, MARINES S.F. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:28:51Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:05Z (GMT). No. of bitstreams: 1 16374.pdf: 618632 bytes, checksum: 99e6c25f834160ee6bcf169bfc0e3c6d (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP; Faculdade de Odontologia, Universidade de Sao Paulo, Sao Paulo
148

Estudo clinico comparativo entre o uso de lasers e metodos convencionais de diagnostico e tratamento de dentes deciduos da presenca de lesao cariosa

PULGA, FABIANE G. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:46:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:19Z (GMT). No. of bitstreams: 1 07906.pdf: 2878645 bytes, checksum: 7759ff26cf400a2aba605cb826d91e7e (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo
149

Avaliacao in vitro da microinfiltracao marginal em restauracoes de classe V com resina composta em dentes bovinos. Influencia da irradiacao laser e sistema adesivo no pre-tratamento dentinario

CARVALHO, WENDELL L. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:48:28Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:39Z (GMT). No. of bitstreams: 1 09064.pdf: 3638993 bytes, checksum: 8325a415e5861bfd1f85383134e3dcee (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo
150

Avaliacao morfologica das superficies do esmalte e do cemento dental apos a irradiacao do laser ER:YAG em diferentes angulacoes

TANNOUS, JOSE T. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:44:44Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:51Z (GMT). No. of bitstreams: 1 07297.pdf: 2897384 bytes, checksum: ade16901adf7663b2eb89bed60b5b413 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

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