Key Points
- Researchers developed a miniaturized all-fiber photoacoustic spectrometer (FPAS) that can detect gases at ppb levels.
- The compact design replaces traditional bulky spectroscopy components. It measures 60 µm in length and 125 µm in diameter and achieves lab-level precision.
- Capable of real-time intravascular CO2 monitoring and yeast fermentation detection.
- It operates with millisecond response times, 1,000x faster than traditional systems. Easily integrates with fiber-optic networks and low-cost laser sources.
Researchers from China have unveiled a groundbreaking miniaturized all-fiber photoacoustic spectrometer (FPAS) capable of detecting trace gases at parts-per-billion (ppb) levels. Published in Advanced Photonics, this innovation is set to transform applications such as environmental monitoring, industrial process control, and biomedical diagnostics, particularly in scenarios requiring minimal invasiveness.
Traditional laser spectroscopy systems rely on bulky components like gas cells, mirrors, and detectors, rendering them unsuitable for confined spaces or intravascular diagnostics. The new FPAS overcomes these limitations by employing photoacoustic spectroscopy (PAS), which detects sound waves generated by gas molecules excited by modulated light.
The FPAS integrates a laser-patterned elastic membrane into a single optical fiber tip, coupled with a silica capillary, forming a microscale Fabry–Perot (F–P) cavity. This design replaces the bulky components of traditional systems with a compact structure that confines and amplifies acoustic waves, ensuring high sensitivity despite its small size. The F–P cavity measures just 60 micrometers in length and 125 micrometers in diameter yet achieves an impressive detection limit of 9 ppb for acetylene gas.
The compact spectrometer also excels in speed, delivering response times of 18 milliseconds—up to 1,000 times faster than conventional systems. Its versatility was demonstrated through real-time carbon dioxide (CO2) monitoring in flowing gas, detecting fermentation in yeast solutions with 100-nanoliter sample volumes, and intravascular blood gas analysis in live rats. Inserted via a syringe, the FPAS measured CO2 levels under varying conditions, eliminating the need for blood sample collection.
Easily integrated with fiber-optic networks and low-cost laser sources, the FPAS is a cost-effective and flexible spectroscopy solution. With its laboratory-level precision, compact form, and low sample volume requirements, the spectrometer holds promise for intravascular diagnostics, lithium-ion battery health monitoring, and gas leak detection in confined spaces.