title: Laser heating of uncoated optics in a convective medium.
abstract: Powerful, long-pulse lasers have a variety of applications. In many applications, optical elements are employed to direct, focus, or collimate the beam. Typically the optic is suspended in a gaseous environment (e.g., air) and can cool by convection. The variation of the optic temperature with time is obtained by combining the effects of laser heating, thermal conduction, and convective loss. Characteristics of the solutions in terms of the properties of the optic material, laser beam parameters, and the environment are discussed and compared with measurements at the Naval Research Laboratory, employing kW-class, 1 µm wavelength, continuous wave lasers and optical elements made of fused silica or BK7 glass. The calculated results are in good agreement with the measurements, given the approximations in the analysis and the expected variation in the absorption coefficients of the glasses used in the experiments.
authors.affiliation: Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, USA. bahman.hafizi@icarusresearch.com
authors.forename: B
authors.initials: B
authors.lastname: Hafizi
authors.forename: A
authors.initials: A
authors.lastname: Ting
authors.forename: D F
authors.initials: DF
authors.lastname: Gordon
authors.forename: P
authors.initials: P
authors.lastname: Sprangle
authors.forename: J R
authors.initials: JR
authors.lastname: Peñano
authors.forename: R F
authors.initials: RF
authors.lastname: Fischer
authors.forename: G P
authors.initials: GP
authors.lastname: DiComo
authors.forename: D C
authors.initials: DC
authors.lastname: Colombant