System for time-resolved laser absorption spectroscopy and its application to high-power impulse magnetron sputtering

Area of Science:

• Plasma Physics
• Spectroscopy
• Materials Science

Background:

• Pulsed plasma discharges are crucial in various technological applications.
• Accurate diagnostics of transient plasma properties are essential for process optimization.
• Existing laser absorption spectroscopy (LAS) methods often lack the temporal resolution required for pulsed plasmas.

Purpose of the Study:

• To develop and construct an apparatus for time-resolved tunable diode laser absorption spectroscopy (TR-LAS).
• To extend continuous-wave LAS methods to a direct triggering method for pulsed plasma diagnostics.
• To enable high-time-resolution measurements of plasma species' temporal evolution.

Main Methods:

• Development of a TR-LAS apparatus based on repetitive sampling.
• Extension of continuous-regime LAS to a direct triggering method.
• Application of TR-LAS for diagnostics of argon metastable species.

Main Results:

• The developed TR-LAS method achieves time resolution less than 1 μs.
• Simultaneous measurement of particle density and kinetic temperature is demonstrated.
• Temporal evolution of argon metastable species was successfully measured during magnetron sputtering.

Conclusions:

• The TR-LAS apparatus provides a powerful tool for diagnosing pulsed plasma processes.
• The method is suitable for periodic plasma applications, including pulsed plasma discharges.
• TR-LAS enables detailed insights into plasma dynamics during thin film deposition.