Optical Science and Engineering ETDs

Publication Date

Summer 5-11-2017

Abstract

Laser-induced damage (LID) limits the performance of optical films and surfaces. Despite intensive study for decades following the invention of laser, the study of LID remains timely and attractive, because for nanosecond laser pulses the LID process is controlled by randomly distributed defects of unknown origin.

Traditional damage tests yield little information about the defects present in optical films and surfaces. These methods record a "yes" or "no" damage result after each test and cannot distinguish the different defects present.

This dissertation focuses on the development of a new kind of laser-induced damage test that measures the actual fluence (intensity) at which damage is initiated in each test. This technique works by identifying the initiation both spatially and temporally. The technique is dubbed Spatially-TEmporally REsolved Optical Laser- Induced Damage (STEREO-LID).

In this dissertation, the use of this new technique to study LID in optical films will be shown. First, it will be shown how the spatial and temporal information is recorded during a single damage event. Second, STEREO-LID will be compared to the ISO standard for damage characterization through a combination of experimental results and Monte Carlo simulations. Third, it will be shown how the statistics of repeated damage fluence measurements can be used to retrieve the defect density distribution function, which characterizes the areal density of defects in the optical coating as a function of damage fluence. Finally, the processes that occur after damage initiation and lead to the formation of ablation craters will be explored through modeling of transmission data obtained during STEREO-LID characterization of an optical coating.

Degree Name

Optical Science and Engineering

Level of Degree

Doctoral

Department Name

Optical Science and Engineering

First Committee Member (Chair)

Wolfgang Rudolph

Second Committee Member

Paul Schwoebel

Third Committee Member

David H. Dunlap

Fourth Committee Member

John Bellum

Keywords

laser damage test, optical coating, defect density distribution, laser-induced damage threshold, nanosecond pulse

Document Type

Dissertation

Language

English

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