Töpfer T, Petrov K P, Mine Y, Jundt D, Curl R F, Tittel F K
Appl Opt. 1997 Oct 20;36(30):8042-9. doi: 10.1364/ao.36.008042.
Design and operation of a compact, portable, room-temperature mid-infrared gas sensor is reported. The sensor is based on continuous-wave difference-frequency generation (DFG) in bulk periodically poled lithium niobate at 4.6 mum, pumped by a solitary GaAlAs diode laser at 865 nm and a diode-pumped monolithic ring Nd:YAG laser at 1064.5 nm. The instrument was used for detection of CO in air at atmospheric pressure with 1 ppb precision (parts in 10(9), by mole fraction) and 0.6% accuracy for a signal averaging time of 10 s. It employed a compact multipass absorption cell with a 18-m path length and a thermoelectrically cooled HgCdTe detector. Precision was limited by residual interference fringes arising from scattering in the multipass cell. This is the first demonstration of a portable high-precision gas sensor based on diode-pumped DFG at room temperature. The use of an external-cavity diode laser can provide a tuning range of 700 cm(-1) and allow the detection of several trace gases, including N(2) O, CO(2), SO(2), H(2) CO, and CH(4).
报道了一种紧凑、便携式室温中红外气体传感器的设计与运行。该传感器基于在4.6微米的块状周期性极化铌酸锂中进行连续波差频产生（DFG），由一个865纳米的孤立GaAlAs二极管激光器和一个1064.5纳米的二极管泵浦单片环形Nd:YAG激光器泵浦。该仪器用于在大气压下检测空气中的一氧化碳，在10秒的信号平均时间内，精度为1 ppb（按摩尔分数计，10⁹分之一），准确度为0.6%。它采用了一个路径长度为18米的紧凑多程吸收池和一个热电冷却的HgCdTe探测器。精度受到多程池中散射产生的残余干涉条纹的限制。这是首次展示基于二极管泵浦DFG的便携式高精度室温气体传感器。使用外腔二极管激光器可提供700厘米⁻¹的调谐范围，并允许检测多种痕量气体，包括N₂O、CO₂、SO₂、H₂CO和CH₄。
