Reflectance Changes Of Metals During Laser Irradiation

William T. Walter

doi:10.1117/12.958027

24 January 1980 Reflectance Changes Of Metals During Laser Irradiation

William T. Walter

Proceedings Volume 0198, Laser Applications in Materials Processing; (1980) https://doi.org/10.1117/12.958027
Event: 23rd Annual Technical Symposium, 1979, San Diego, United States

Abstract

The reflectance behavior of a target surface during laser irradiation determines the laser energy which is directly absorbed. Experimentally, the reflectance of a metal surface has been observed to undergo a sharp and substantial decrease during an intense laser pulse. Explanations have been offered based on an increase in electron-phonon collision frequency as the temperature of the metal surface rises to the melting point of the metal. It is doubtful, however, that the temperature dependence of a Drude-type free-electron model can explain the substantial reflectance changes reported, particularly for high conductivity metals such as copper. Three other classes of explanations have been proposed: 1) deformation of the metal surface, 2) plasma formation in the front of the target, or 3) a nonlinear process causing enhanced absorption within the metal. Specular and total reflectances of metal surfaces during ruby laser irradiation have been measured at the Polytechnic. The laser energy absorbed has been calculated and the temperature history of the metal surface determined using a one-dimensional heat-conduction approach. Reflectance and temperature histories have been related to permanent changes observed in the metal target surface. Only at temperatures significantly above the melting point of the metal does a substantial decrease in the total reflectance occur.

Citation Download Citation

William T. Walter "Reflectance Changes Of Metals During Laser Irradiation", Proc. SPIE 0198, Laser Applications in Materials Processing, (24 January 1980); https://doi.org/10.1117/12.958027

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