Compact and Low-Power-Consumption CO Sensor Using a QCL with Intermittent Scanning Technique

A compact and low-power-consumption gas sensor using a quantum cascade laser (QCL) emitting at 4.6 μm for measurement of carbon monoxide (CO) was proposed and experimentally demonstrated. A compact sensor structure with a physical dimension of 14 × 10 × 6.5 cm3 was designed. A new intermittent scanning technique was used to drive the QCL to reduce the power consumption of the system. In this technique, the power consumption of the sensor is as low as 1.08 W, which is about 75% lower than the conventional direct absorption technology. The stability of the CO sensor was demonstrated by continuously monitoring CO concentration for more than 1 h. In the concentration range of 10 ppm to 500 ppm, the CO sensor exhibited a satisfactory linear response (R-square = 0.9998). With an integration time of 202 s, the minimum detection limit was increased to 4.85 ppb, based on an Allan deviation analysis.