The absorption spectra and wavelength modulation spectroscopy (WMS) of ${\mathrm{NO}}_2$ using a tunable, external cavity CW quantum cascade laser operating at room temperature in the region of 1625 to $1645{\mathrm{cm}}^{-1}$ are reported. The external cavity quantum cascade laser enabled us to record continuous absorption spectra of low concentrations of ${\mathrm{NO}}_2$ over a broad range ( $\sim 16{\mathrm{cm}}^{-1}$ ), demonstrating the potential for simultaneously recording the complex spectra of multiple species. This capability allows the identification of a particular species of interest with high sensitivity and selectivity. The measured spectra are in excellent agreement with the spectra from the high-resolution transmission molecular absorption database [ J. Quant. Spectrosc. Radiat. Transfer 96, 139–204 (2005)]. We also conduct WMS for the first time using an external cavity quantum cascade laser, a technique that enhances the sensitivity of detection. By employing WMS, we could detect low-intensity absorption lines, which are not visible in the simple absorption spectra, and demonstrate a minimum detection limit at the $100\mathrm{ppb}$ level with a short-path absorption cell. Details of the tunable, external cavity quantum cascade laser system and its performance are discussed.

© 2009 Optical Society of America

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

Related Journal Articles

• On-line Multicomponent Trace-Gas Analysis With a Broadly Tunable Pulsed Difference-Frequency Laser Spectrometer (AO)
• Ultrasensitive Absorption Spectroscopy with a High-Finesse Optical Cavity and Off-Axis Alignment (AO)
• Variable Pressure Infrared Diode Laser Spectroscopy: A New Method for Trace-Gas Monitoring (AO)
• Enhanced sensitivity for the detection of trace gases using multiple line integrated absorption spectroscopy (AO)
• Enhancement of trace gas detection by integrating wavelength modulated spectra across multiple lines (AO)

Related Conference Papers

• A quantum cascade laser-based sensor for measurement of the stable isotopomers of carbon dioxide
• Temperature Impact on the Long-Term Stability of a Portable Laser Spectroscopic CO2 Sensor
• Temperature Impact on the Long-Term Stability of a Portable Laser Spectroscopic CO2 Sensor
• In-Line Reference Cell for Real-Time Calibration of Laser Absorption Spectrometers
• Temperature Impact on the Long-Term Stability of a Portable Laser Spectroscopic CO2 Sensor