Real-time monitoring of hydrogen cyanide (HCN) and ammonia (NH₃) emitted by Pseudomonas aeruginosa.

We present the real-time monitoring of hydrogen cyanide (HCN) production from Pseudomonas aeruginosa (P. aeruginosa) strains in vitro, using laser-based photoacoustic spectroscopy. Simultaneously, the production of ammonia (NH3) was measured, and the influence of different factors (e.

Optical parametric oscillator-based photoacoustic detection of hydrogen cyanide for biomedical applications.

A versatile, continuous wave, optical parametric oscillator is used in combination with photoacoustic spectroscopy for long-term trace gas experiments of volatile compounds emitted by biological samples. The optical parametric oscillator-based spectrometer (wavelength near 3 μm, 8-MHz linewidth, output power ∼1 W) is successfully tested for the detection of hydrogen cyanide (HCN) emission from clover leaves, and Pseudomonas bacteria; in addition, the presence of HCN in exhaled human breath is measured. For specific experiments, the spectrometer is operated continuously up to 10 days and has a detection limit of 0.

Real-time, subsecond, multicomponent breath analysis by Optical Parametric Oscillator based Off-Axis Integrated Cavity Output Spectroscopy.

Breath analysis is an attractive field of research, due to its high potential for non-invasive medical diagnostics. Among others, laser-based absorption spectroscopy is an excellent method for the detection of gases in exhaled breath, because it can combine a high sensitivity with a good selectivity, and a high temporal resolution. Here, we use a fast-scanning continuous wave, singly-resonant Optical Parametric Oscillator (wavelength range between 3 and 4 μm, linewidth 40 MHz, output power > 1 W, scanning speed 100 THz/s) with Off-Axis Integrated Cavity Output Spectroscopy for rapid and sensitive trace gas detection.

Optical parametric oscillator based off-axis integrated cavity output spectroscopy for rapid chemical sensing.

An optical parametric oscillator (OPO), pumped by a fiber-amplified diode laser, is combined with off-axis integrated cavity output spectroscopy (OA-ICOS). The cw OPO (power 1.2 W, tunability 3-4 μm, 5 cm(-1) mode-hop-free tuning) has a tuning speed of 100 THz/s, which is ideal for rapid and sensitive trace gas detection.