A Rapidly Tunable Laser System for Measurements of NH2 at 597 nm Behind Reflected Shock Waves
2024

Rapidly Tunable Laser System for NH2 Measurements

publication Evidence: high

Author Information

Author(s): Sean Clees, Spencer C. Barnes, Taylor M. Rault, Christopher L. Strand, Ronald K. Hanson

Primary Institution: Stanford University

Hypothesis

Can a rapidly tunable laser system effectively measure NH2 radicals at 597 nm behind reflected shock waves?

Conclusion

The developed laser system successfully measured NH2 concentrations during NH3 pyrolysis in shock tube experiments.

Supporting Evidence

  • The laser system achieved a second-harmonic generation efficiency of 109%/W.
  • It demonstrated rapid-tuning capabilities with a scan rate of up to 900 kHz.
  • The system maintained optical frequency and power stability within standard deviations of 48 MHz and 0.4% over 20 minutes.
  • Measurements were conducted using four different laser absorption spectroscopy techniques.

Takeaway

Scientists built a special laser that can quickly change colors to measure a gas called NH2, which is important for understanding how ammonia breaks down.

Methodology

The system used a distributed feedback diode laser, an optical amplifier, and a periodically poled lithium niobate waveguide for second-harmonic generation.

Limitations

The study was limited to specific temperature and pressure ranges during the shock tube experiments.

Digital Object Identifier (DOI)

10.3390/s24247920

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