Biomaterial Database

Investigation of stress induced by CO2 laser processing of fused silica optics for laser damage growth mitigation. 2009

Laurent Gallais, and Philippe Cormont, and Jean-Luc Rullier

Institut Fresnel, CNRS, Aix-Marseille Université, Ecole Centrale Marseille, Campus de Saint-Jérôme, 13013 Marseille, France. laurent.gallais@fresnel.fr

Laser damage mitigation' is a process developed to prevent the growth of nanosecond laser-initiated damage sites under successive irradiation. It consists of re-fusing the damage area with a CO2 laser. In this paper we investigate the stress field created around mitigated sites which could have an influence on the efficiency of the process. A numerical model of CO2 laser interaction with fused silica is developed. It takes into account laser energy absorption, heat transfer, thermally induced stress and birefringence. Residual stress near mitigated sites in fused silica samples is characterized with specific photoelastic methods and theoretical data are compared to experiments. The stress distribution and quantitative values of stress levels are obtained for sites treated with the CO2 laser in various conditions of energy deposition (beam size, pulse duration, incident power). The results provided evidence that the presence of birefringence/residual stress around the mitigated sites has an effect on their laser damage resistance.

UI	MeSH Term	Description	Entries
D011829	Radiation Dosage	The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).	Sievert Units,Dosage, Radiation,Gray Units,Gy Radiation,Sv Radiation Dose Equivalent,Dosages, Radiation,Radiation Dosages,Units, Gray,Units, Sievert
D004307	Dose-Response Relationship, Radiation	The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.	Dose Response Relationship, Radiation,Dose-Response Relationships, Radiation,Radiation Dose-Response Relationship,Radiation Dose-Response Relationships,Relationship, Radiation Dose-Response,Relationships, Radiation Dose-Response
D012822	Silicon Dioxide	Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.	Silica,Aerosil,Aerosil 380,Cristobalite,Quso G-32,Quso G32,Tridymite,380, Aerosil,Dioxide, Silicon,G32, Quso,Quso G 32
D013314	Stress, Mechanical	A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.	Mechanical Stress,Mechanical Stresses,Stresses, Mechanical
D013499	Surface Properties	Characteristics or attributes of the outer boundaries of objects, including molecules.	Properties, Surface,Property, Surface,Surface Property
D054020	Lasers, Gas	Lasers in which a gas lasing medium is stimulated to emit light by an electric current or high-frequency oscillator.	Argon Ion Lasers,CO2 Lasers,Carbon Dioxide Lasers,Copper Vapor Lasers,Gas Lasers,Gold Vapor Lasers,Helium Lasers,Helium Neon Gas Lasers,Metal Vapor Lasers,Nitrogen Lasers,Xenon Ion Lasers,HeNe Lasers,Lasers, Argon Ion,Lasers, CO2,Lasers, Carbon Dioxide,Lasers, Copper Vapor,Lasers, Gold Vapor,Lasers, Helium,Lasers, Helium Neon Gas,Lasers, Metal Vapor,Lasers, Nitrogen,Lasers, Xenon Ion,Argon Ion Laser,CO2 Laser,Carbon Dioxide Laser,Copper Vapor Laser,Dioxide Laser, Carbon,Dioxide Lasers, Carbon,Gas Laser,Gold Vapor Laser,HeNe Laser,Helium Laser,Ion Laser, Argon,Ion Laser, Xenon,Ion Lasers, Argon,Ion Lasers, Xenon,Laser, Argon Ion,Laser, CO2,Laser, Carbon Dioxide,Laser, Copper Vapor,Laser, Gas,Laser, Gold Vapor,Laser, HeNe,Laser, Helium,Laser, Metal Vapor,Laser, Nitrogen,Laser, Xenon Ion,Lasers, HeNe,Metal Vapor Laser,Nitrogen Laser,Vapor Laser, Copper,Vapor Laser, Gold,Vapor Laser, Metal,Vapor Lasers, Copper,Vapor Lasers, Gold,Vapor Lasers, Metal,Xenon Ion Laser