Entwicklung eines neuen Pumpkonzeptes für ein miniaturisiertes, diodengepumptes Er:YSGG-Lasersystem für den zahnmedizinischen Einsatz

Erbium solid-state laser systems have gained in importance in medicine over the last years. Because of the high absorption of their emission wavelengths of 2.7-3 µm in water and hydroxyapatit these lasers are very well suited for hard and soft tissue applications. In dentistry erbium lasers are used for cavity preparation, surgery, periodontics, and endodontics. All commercial available erbium lasers are flash-lamp pumped and and therefore feature only a low slope efficiency in the order of magnitude of 1%. This results in high heat losses which require the laser to be equipped with a sumptuous cooling. Since also a high voltage supply is neccessary for a flash-lamp pumped laser, clinically used erbium lasers are bulky supplementary devices. The miniaturization of an erbium:YSGG (erbium Yttrium Scandium Gallium Granat) was achieved using a newly developed pump technique. The presented thesis introduces the new pump concept of "multi-reflective pumping" which allows to integrate an erbium laser head into a dental handpiece for the very first time. This pump concept is based upon resonant excitation of the upper laser level of the erbium ion with infrared pump radiation of a wavelength of 970 nm. The pump radiation is delivered by pump laser diodes. The usage of these diodes also allows to build such an erbium laser without a high voltage supply. To describe the diode pumped laser process a theoretical model of the erbium ion was developed and mathematically described as a coupled system of differential rate equations. This system of equations is solved numerically and the used solving approaches and the results are discussed. The multi-reflective pumping concept is explained and optimized with a raytracing algorithm. Different experimental setups were assembled and tested for their output energies and their slope efficiencies. Output energies of 5,5 mJ were achieved with a pump energy of 125 mJ yielding a slope efficiency of 7.5%. This value increases to 10.5% when the theoretical pump losses are included. For the laser threshold values between 1.5 and 2.25 mJ per mm^3 were observed. For the first time is has been demonstrated that it is possible to build a miniaturized erbium laser head of a diameter of 10.5 mm and a length below 3 cm including resonator and cooling circuit.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2003

Author dc:creator

• Franzen, René

Contributors dc:contributor

• Gutknecht, Norbert

• info:eu-repo/classification/ddc/610
• Medizin
• Laser
• Erbium
• Zahnheilkunde
• Laserzahnheilkunde
• Multireflexion

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-121072%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:59271