Applied Physics B

, Volume 85, Issue 2, pp 219–222

Two-tone frequency modulation spectroscopy for ambient-air trace gas detection using a portable difference-frequency source around 3 μm

  • P. Maddaloni
  • P. Malara
  • G. Gagliardi
  • P. De Natale
Article

DOI: 10.1007/s00340-006-2299-6

Cite this article as:
Maddaloni, P., Malara, P., Gagliardi, G. et al. Appl. Phys. B (2006) 85: 219. doi:10.1007/s00340-006-2299-6

Abstract

We report a portable, widely tunable, mW-power mid-infrared spectrometer based on difference-frequency generation in a periodically poled lithium-niobate crystal, realized in a compact and robust design. The analytical performance for real-time monitoring of natural-abundance trace gases in ambient air is evaluated, pointing out the possibility of field applications. In a direct-absorption scheme, a minimum detectable concentration of 3 ppb Hz-1/2 is demonstrated around 3.3 μm for methane at atmospheric pressure. The sensitivity is further improved by using a two-tone frequency modulation spectroscopy technique that provides an enhancement of a factor of 100 in the signal-to-noise ratio, thus yielding a minimum absorption coefficient of 5.3×10-9 cm-1 Hz-1/2.

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • P. Maddaloni
    • 1
  • P. Malara
    • 1
  • G. Gagliardi
    • 1
  • P. De Natale
    • 1
  1. 1.Istituto Nazionale di Ottica Applicata and European Laboratory for Nonlinear Spectroscopy (LENS), Comprensorio ‘A. Olivetti’Consiglio Nazionale delle RicerchePozzuoliItaly