Application of a characterized difference-frequency laser source to carbon monoxide trace detection  

作　　者：Alireza Khorsandi Zahra Shabani Monireh Ranjbar S. Ali Hoseinzadeh Salati 

机构地区：[1]Department of Physics,University of Isfahan,81746-73441 Isfahan,Iran

出　　处：《Chinese Physics B》2012年第6期257-263,共7页中国物理B（英文版）

摘　　要：A tunable continuous wave（cw） mid-infrared（MIR） laser based on difference-frequency generation（DFG） in a 1.5-cm long AgGaS2 nonlinear crystal for trace gas detection is reported.Two visible and near-infrared diode lasers were used as pump and signal sources.The MIR-DFG laser was tunable in a wavelength range of 4.75 μm-4.88 μm.The phase-matching（PM） condition was non-critically achieved by adjusting the temperature of the crystal for fixed pairs of input pump and signal wavelengths.The required PM temperatures of the generated MIR-DFG wavelengths have been calculated by using three sets of recent Sellmeier equations and the temperature-dispersion equations of AgGaS2 given by Willer U,et al.（Willer U,Blanke T and Schade W 2001 Appl.Opt.40 5439）.Then the calculated PM temperatures are compared with the experimental values.The performance of the MIR-DFG laser is shown by the trace detection of the P（16） carbon monoxide（12C16O） absorption line in a laboratory-fabricated absorption cell.The enhanced sensitivity of about 0.6×10 4 was obtained through the long path absorption provided by consecutive reflections between coated cylindrical mirrors of a constructed cell.A tunable continuous wave（cw） mid-infrared（MIR） laser based on difference-frequency generation（DFG） in a 1.5-cm long AgGaS2 nonlinear crystal for trace gas detection is reported.Two visible and near-infrared diode lasers were used as pump and signal sources.The MIR-DFG laser was tunable in a wavelength range of 4.75 μm-4.88 μm.The phase-matching（PM） condition was non-critically achieved by adjusting the temperature of the crystal for fixed pairs of input pump and signal wavelengths.The required PM temperatures of the generated MIR-DFG wavelengths have been calculated by using three sets of recent Sellmeier equations and the temperature-dispersion equations of AgGaS2 given by Willer U,et al.（Willer U,Blanke T and Schade W 2001 Appl.Opt.40 5439）.Then the calculated PM temperatures are compared with the experimental values.The performance of the MIR-DFG laser is shown by the trace detection of the P（16） carbon monoxide（12C16O） absorption line in a laboratory-fabricated absorption cell.The enhanced sensitivity of about 0.6×10 4 was obtained through the long path absorption provided by consecutive reflections between coated cylindrical mirrors of a constructed cell.

关 键 词：difference-frequency generation AgGaS2 crystal multi-pass cell 

分 类 号：TN247[电子电信—物理电子学]