First detection of transitions in the second quadrupole overtone band of nitrogen near 1.44 μm by CW-CRDS with 6 × 10−13 cm−1 sensitivity

- Very high sensitivity CW-Cavity Ring Down spectroscopy of nitrogen near 1.44 μm.
- A record sensitivity of αmin ∼ 6 × 10−13 cm−1 is achieved by averaging CW-CRDS spectra.
- Two electric quadrupole transitions of the 3-0 band of 14N2 are detected.
- The measured lines are among the weakest ever detected in the laboratory.
- Good agreement with theoretical values for the line positions and line intensities.