Mid-infrared surface transmitting and detecting quantum cascade device for gas-sensing.

Area of Science:

• Optoelectronics
• Chemical Sensing
• Infrared Spectroscopy

Background:

• Gas sensing technologies are crucial for environmental monitoring and industrial safety.
• Existing methods often require complex setups or limited interaction regions.
• Mid-infrared (mid-IR) spectroscopy offers unique molecular fingerprinting capabilities for gas detection.

Purpose of the Study:

• To develop a novel bi-functional mid-infrared device for gas sensing.
• To integrate a distributed feedback ring quantum cascade laser with a bi-functional detector on a single chip.
• To enable efficient gas detection through a long analyte interaction region and surface operation mode.

Main Methods:

• Monolithic integration of a ring quantum cascade laser and a bi-functional detector material.
• Utilizing a surface-emitting and surface-detecting configuration for mid-IR radiation.
• Employing a double-pass gas cell configuration for enhanced analyte interaction.

Main Results:

• Demonstrated a single-mode, low-divergence emission at 6.5 μm.
• Achieved detection of isobutane (2-methylpropane) and propane with high concentration ranges (0-90% and 0-70%, respectively).
• Validated the device's suitability for sensing gaseous analytes requiring long interaction paths.

Conclusions:

• The bi-functional mid-infrared device offers a compact and efficient solution for gas sensing.
• The integrated laser-detector design enables sensitive detection of various gases.
• The platform is scalable for 2D array integration with multi-frequency capabilities.