RESUMO
For the first time, lasing at NV- centers in an optically pumped diamond sample is achieved. A nanosecond train of 150-ps 532-nm laser pulses was used to pump the sample. The lasing pulses have central wavelength at 720 nm with a spectrum width of 20 nm, 1-ns duration and total energy around 10 nJ. In a pump-probe scheme, we investigate lasing conditions and gain saturation due to NV- ionization and NV0 concentration growth under high-power laser pulse pumping of diamond crystal.
RESUMO
Hollow-core photonic-crystal fibres (PCFs) for the delivery of high-fluence laser radiation capable of ablating tooth enamel are developed. Sequences of picosecond pulses of 1.06 microm Nd:YAG-laser radiation with a total energy of about 2 mJ are transmitted through a hollow-core photonic-crystal fibre with a core diameter of approximately 14 microm and are focused on a tooth surface in vitro to ablate dental tissue. The hollow-core PCF is shown to support the single-fundamental-mode regime for 1.06 microm laser radiation, serving as a spatial filter and allowing the laser beam quality to be substantially improved. The same fibre is used to transmit emission from plasmas produced by laser pulses on the tooth surface in the backward direction for detection and optical diagnostics.
Assuntos
Cristalização/métodos , Esmalte Dentário/efeitos da radiação , Esmalte Dentário/cirurgia , Tecnologia de Fibra Óptica/instrumentação , Terapia a Laser/instrumentação , Terapia a Laser/métodos , Procedimentos Cirúrgicos Bucais/instrumentação , Esmalte Dentário/patologia , Relação Dose-Resposta à Radiação , Análise de Falha de Equipamento , Tecnologia de Fibra Óptica/métodos , Humanos , Técnicas In Vitro , Lasers , Procedimentos Cirúrgicos Bucais/métodos , Porosidade , Espalhamento de RadiaçãoRESUMO
Sequences of picosecond pulses of 1.06-microm Nd:YAG laser radiation with a total energy of approximately 2 mJ are transmitted through a hollow-core photonic-crystal fiber with a core diameter of approximately 14 microm and are focused onto a tooth's surface in vitro to ablate dental tissue. The hollow-core photonic-crystal fiber is shown to support the single-fundamental-mode regime for 1.06-microm laser radiation, serving as a spatial filter and allowing the laser beam's quality to be substantially improved. The same fiber is used to transmit emission from plasmas produced by laser pulses onto the tooth's surface in the backward direction for detection and optical diagnostics.