Cascade Technologies Ltd. has developed a gas-detection technology that uses quantum cascade lasers and is suitable for oil and gas, defense, security and medical diagnostics applications. The portable gas sensor works in real time, detects with parts-per-trillion sensitivity and operates at room temperature. It enables compound identification and simultaneous measurement of multiple gases. Mid-infrared semiconductor lasers provide the light source, which is passed through a gas cell to a detector. Changes in light intensity caused by absorption by the gases of interest produce a chemical fingerprint.