Detection of subsurface damage: studies in sapphire

David R. Black; Robert S. Polvani; Linda M. Braun; Bernard J. Hockey; Grady S. White

doi:10.1117/12.277036

27 June 1997 Detection of subsurface damage: studies in sapphire

David R. Black, Robert S. Polvani, Linda M. Braun, Bernard J. Hockey, Grady S. White

Proceedings Volume 3060, Window and Dome Technologies and Materials V; (1997) https://doi.org/10.1117/12.277036
Event: AeroSense '97, 1997, Orlando, FL, United States

Abstract

A variety of nondestructive characterization techniques has been used to detect and measure subsurface damage in single- crystal sapphire to develop methods suitable to inspect high performance optics for sub-surface damage. These techniques include polarized light microscopy, x-ray diffraction topography, transmission electron microscopy (TEM) and Raman spectroscopy. TEM examination shows that for ground surfaces damage can extend up to 6 - 7 micrometers into the bulk and includes cracks, twins and dislocations, while under polished surfaces only dislocations are seen. X-ray diffraction topography can image defects such as long-range strain, dislocations, residual surface scratches (not visible optically) and low-angle grain boundaries (lineage). Polarized light is also sensitive to strain and provides a relatively easy method for detecting defects such as cracks and lineage. Of all of the techniques Raman spectroscopy offers the best potential for quantifying strain in terms of stress.

Citation Download Citation

David R. Black, Robert S. Polvani, Linda M. Braun, Bernard J. Hockey, and Grady S. White "Detection of subsurface damage: studies in sapphire", Proc. SPIE 3060, Window and Dome Technologies and Materials V, (27 June 1997); https://doi.org/10.1117/12.277036

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available