Location

La Jolla, CA

Start Date

1-1-1989 12:00 AM

Description

Thermal wave technology has proven to be a very effective means for investigating the near surface region of several different materials. Although there are many methods for generating and detecting thermal waves the most desirable for quantitative NDE are the noncontact and nondamaging laser methods. When a material is excited with an intensity-modulated laser pump beam a thermal wave is generated within the near surface of the sample. Since the complex refractive index of most materials depends on temperature, the laser pump induced modulations in the local temperature of the sample will induce a corresponding modulation in the local refractive index. This variation in refractive index can in turn be detected through the modulation in the reflectance of a laser probe beam from the surface of the material [1,2]. This method is not only a highly effective method for generating and detecting thermal waves, but also permits thermal wave measurements to be performed with micron scale spatial resolution by utilizing highly focused pump and probe laser beams.

Volume

8B

Chapter

Chapter 6: Electronic Materials and Devices

Section

Electronic Materials and Devices

Pages

1195-1201

DOI

10.1007/978-1-4613-0817-1_149

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Thermal Wave Characterization of Semiconductors and Superconductors

La Jolla, CA

Thermal wave technology has proven to be a very effective means for investigating the near surface region of several different materials. Although there are many methods for generating and detecting thermal waves the most desirable for quantitative NDE are the noncontact and nondamaging laser methods. When a material is excited with an intensity-modulated laser pump beam a thermal wave is generated within the near surface of the sample. Since the complex refractive index of most materials depends on temperature, the laser pump induced modulations in the local temperature of the sample will induce a corresponding modulation in the local refractive index. This variation in refractive index can in turn be detected through the modulation in the reflectance of a laser probe beam from the surface of the material [1,2]. This method is not only a highly effective method for generating and detecting thermal waves, but also permits thermal wave measurements to be performed with micron scale spatial resolution by utilizing highly focused pump and probe laser beams.