我們建立了一套高準確的波長可調中紅外光源，此光源包含了光學參量振盪器(Optical Parametric Oscillator, OPO)、碘分子穩頻雷射系統、可調式偏差鎖頻系統、光頻梳及偏差鎖頻系統。這套光源可以產生2.4~4.0 μm的中紅外光，閒(idler)光功率可以達2 W。
OPO的泵浦(pump)光頻率是由碘分子穩頻雷射系統和可調式偏差鎖頻系統決定，我們利用偏差鎖頻技術，將pump光頻率鎖在碘分子穩頻雷射上，同時將OPO的訊號(signal)光頻率利用偏差鎖頻技術鎖在光頻梳上。如此藉由改變pump光頻率就可以準確控制idler光頻率。
我們透過改善OPO pump光頻率來提升OPO idler光頻率的準確度，使OPO idler光在寬頻輸出下，頻率精準度可以達8 kHz以下，掃頻範圍可以達3 GHz以上。
我們利用這套光源量測了CH_4 P(7) F_2^((2))躍遷的頻率，除了可以校正我們的系統外，還可以證實OPO idler光頻率輸出的準確度。我們也量測了H_3^+ R(1,0)躍遷的頻率，譜線的準確度約在200 kHz以下，與其他團隊的量測結果之差異也在1 MHz以下。

This study deals with the set-up of a high-accuracy and wavelength tunable mid-infrared light source. The light source includes Optical Parametric Oscillator (OPO), I2-stabilized Nd:YAG laser system, tunable offset locking system, optical frequency comb and frequency offset locking system. This light source is tunable in the mid-infrared ranging from 2.4 µm to 4.0 µm. The maximum power of the idler light is ~ 2 W.
OPO pump frequency is determined by I2-stabilized Nd:YAG laser system and tunable offset locking system. OPO pump frequency is locked on I2-stabilized Nd:YAG laser system by offset locking technology, while OPO signal frequency is locked on optical frequency comb by offset locking technology. So the change in the pump frequency precisely controls the idler frequency.
The OPO idler frequency accuracy can be enhanced by improving the OPO pump frequency. We have enhanced the OPO idler frequency accuracy to 8 kHz and sweep range to 3GHz by improving the OPO pump frequency.
We have used this light source to measure the transition frequency of CH_4 P(7) F_2^((2)), In addition to correcting our system, it can also improve OPO idler frequency accuracy. We have also measured the transition frequency of H_3^+ R(1,0). The accuracy of the transition frequency is about 200 kHz or less, and the difference between the measurement results of ours and the other group is ~ 1 MHz or less.

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