Spatially resolved measurements of thermal stresses by picosecond time-domain probe beam deflection

David G. Cahill, Xuan Zheng, Ji Cheng Zhao

Research output: Contribution to journalArticle

Abstract

Measurements of thermally induced strains with micron-scale lateral spatial resolution, picosecond time resolution, and sub-picometer vertical sensitivity are achieved using a newly developed experimental method, time-domain probe beam defection (TD-PBD). TD-PBD is a pump-probe optical technique that combines an ultrafast laser oscillator as the light source, high frequency (10MHz) modulation of the pump beam, and a wide range of time delays (0-4ns) between the pump and probe. Deflections of the probe beam are measured by a position sensitive detector and an rf lockin amplifier. The beam-deflection data are analyzed using a detailed model of heat transport and thermally generated stresses and strains. Comparisons between the model and the data enable quantitative measurements of the coefficient of thermal expansion with a spatial resolution of 4m.

Original languageEnglish (US)
Pages (from-to)9-14
Number of pages6
JournalJournal of Thermal Stresses
Volume33
Issue number1
DOIs
StatePublished - Jan 1 2010

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Keywords

  • Coefficient of thermal expansion
  • Combinatorial materials science
  • Pump-probe techniques
  • Ultrafast laser metrology

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Science(all)

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