Standoff analysis of laser-produced plasmas using laser-induced fluorescence

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Laser ablation (LA) is a technique used for material analysis.
• Standoff detection of elemental species is crucial for various applications.
• Traditional emission spectroscopy methods can be limited in sensitivity and resolution.

Purpose of the Study:

• To investigate the application of laser-induced fluorescence (LIF) for standoff analysis of laser ablation (LA) plumes.
• To demonstrate the capability of LIF for detecting aluminum (Al) species at a distance of approximately 10 meters.
• To compare the performance of LIF with thermally excited emission for LA plume analysis.

Main Methods:

• Generation of nanosecond laser-produced plasma plumes from aluminum samples at a standoff distance.
• Utilizing continuous wave (cw) tunable laser to resonantly excite an Al transition at 394.4 nm.
• Collecting direct-line fluorescence signal at 396.15 nm.
• Achieving spectral resolution by scanning the cw tunable LIF laser across the Al transition.

Main Results:

• Successful standoff detection of Al species in LA plumes at a distance of ~10 meters.
• LIF demonstrated enhanced signal intensity compared to thermally excited emission.
• LIF provided improved emission persistence and spectral resolution.
• The method allowed for the analysis of both major and minor Al species.

Conclusions:

• Laser-induced fluorescence is a viable and effective technique for standoff analysis of laser ablation plumes.
• LIF offers significant advantages in signal intensity, persistence, and spectral resolution over conventional methods.
• This approach has potential for remote elemental analysis in various fields.