Location

Brunswick, ME

Start Date

1-1-1997 12:00 AM

Description

The mirage technique (with a single modulated heating source) [1–3] has been successfully applied to study the thermal, optical and electronic properties of solid state materials. Its advantages of being nondestructive, noncontact and high sensitivity make it a powerful and versatile tool. In this paper, we propose a new technique which is the same mirage technique, but with a dipole source. It inherits the advantages of the traditional mirage technique but overcomes some of the shortcomings. The traditional mirage technique generally gathers data by positional scanning, which, in additional to being time-consuming, introduces noise associated with the mechanical movement and makes the analysis susceptible to the nonuniformity of the sample. The nonuniformity can be unevenness in optical properties, surface roughness, or simply grain boundaries. With a dipole source, it is possible to gather data by frequency sweeping. In doing so, the new technique is free from those shortcomings connected with positional scanning. Also, the use of a dipole heating source nearly doubles the signal magnitude with the same amount of unmodulated heating beam power. We use this technique to study the thermal properties of CVD diamonds, glass and silicon samples. The results show that this technique has capabilities of measuring thermal diffusivity with both good resolution and wide range.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

16A

Chapter

Chapter 1: Standard Techniques

Section

Thermal Waves

Pages

379-382

DOI

10.1007/978-1-4615-5947-4_50

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

A Dipole Thermal Wave Source and Mirage Detection

Brunswick, ME

The mirage technique (with a single modulated heating source) [1–3] has been successfully applied to study the thermal, optical and electronic properties of solid state materials. Its advantages of being nondestructive, noncontact and high sensitivity make it a powerful and versatile tool. In this paper, we propose a new technique which is the same mirage technique, but with a dipole source. It inherits the advantages of the traditional mirage technique but overcomes some of the shortcomings. The traditional mirage technique generally gathers data by positional scanning, which, in additional to being time-consuming, introduces noise associated with the mechanical movement and makes the analysis susceptible to the nonuniformity of the sample. The nonuniformity can be unevenness in optical properties, surface roughness, or simply grain boundaries. With a dipole source, it is possible to gather data by frequency sweeping. In doing so, the new technique is free from those shortcomings connected with positional scanning. Also, the use of a dipole heating source nearly doubles the signal magnitude with the same amount of unmodulated heating beam power. We use this technique to study the thermal properties of CVD diamonds, glass and silicon samples. The results show that this technique has capabilities of measuring thermal diffusivity with both good resolution and wide range.