[Incoherent broadband cavity enhanced absorption spectroscopy based on LED]

Area of Science:

• Spectroscopy
• Cavity Enhanced Absorption Spectroscopy
• Optical Physics

Context:

• Nitrogen dioxide (NO2) is a key air pollutant.
• Accurate and sensitive detection of NO2 is crucial for environmental monitoring and atmospheric research.
• Existing spectroscopic methods may lack the required sensitivity or portability for certain applications.

Purpose:

• To develop a high-sensitivity incoherent broadband cavity enhanced absorption spectroscopy (IB-CEAS) system.
• To utilize a high power LED as the light source for enhanced sensitivity.
• To demonstrate the system's capability in detecting low concentrations of NO2.

Summary:

• A novel IB-CEAS system was engineered using a high power LED light source and a high finesse optical cavity.
• The system achieved high sensitivity by measuring NO2 absorption spectra between 472.3-479.3 nm.
• Differential spectral fitting enabled retrieval of NO2 concentrations with statistical uncertainties as low as 3.1 ppb (ng x mL(-1)) over an 80 s averaging period.

Impact:

• This development offers a more sensitive and potentially portable spectroscopic technique for gas detection.
• It provides a valuable tool for precise environmental monitoring of pollutants like NO2.
• The methodology can be adapted for the detection of other trace gases.