TY - CONF
AU - Jun Ye
AU - L.-S. Ma
AU - John Hall
AB - High detection sensitivities of quantum absorptions are important in many research fields of physics, chemistry and biology.  In this paper we present our latest results on the ultrasensitive molecular overtone spectroscopy using the cavity-enhanced frequency modulation (FM) technique.  The principle of this method makes use of a high-finesse external cavity to enhance the intrinsic resonance contrast, while an FM modulation approach provides shot-noise limited signal recovery.  Ideal  matching of the FM sideband frequency to the cavity free-spectral-range makes the detection process insensitive to the laser frequency noise relative to the cavity, while at the same time overcomes the cavity bandwidth limit.  Working with a 1064-nm Nd:YAG laser, we have obtained sub-Doppler overtone resonances of HCCD, HCCH and CO2 molecules.  A detection sensitivity of 5 x 10-13 of integrated absorption (1 x 10-14 / cm) over 1-s averaging time has been achieved.  The resultant high signal-to-noise ratio of the weak resonance produces excellent laser frequency stabilization.



BT - SPIE Proceedings Optoelectronics and High-Power Lasers & Applications: Methods for Ultrasensitive Detection
CY - San Jose, CA
DA - 1998-04
DO - 10.1117/12.308366
N2 - High detection sensitivities of quantum absorptions are important in many research fields of physics, chemistry and biology.  In this paper we present our latest results on the ultrasensitive molecular overtone spectroscopy using the cavity-enhanced frequency modulation (FM) technique.  The principle of this method makes use of a high-finesse external cavity to enhance the intrinsic resonance contrast, while an FM modulation approach provides shot-noise limited signal recovery.  Ideal  matching of the FM sideband frequency to the cavity free-spectral-range makes the detection process insensitive to the laser frequency noise relative to the cavity, while at the same time overcomes the cavity bandwidth limit.  Working with a 1064-nm Nd:YAG laser, we have obtained sub-Doppler overtone resonances of HCCD, HCCH and CO2 molecules.  A detection sensitivity of 5 x 10-13 of integrated absorption (1 x 10-14 / cm) over 1-s averaging time has been achieved.  The resultant high signal-to-noise ratio of the weak resonance produces excellent laser frequency stabilization.



PB - SPIE
PP - San Jose, CA
PY - 1998
EP - 85
T2 - SPIE Proceedings Optoelectronics and High-Power Lasers & Applications: Methods for Ultrasensitive Detection
TI - Cavity-enhanced frequency modulation spectroscopy: advancing optical detection sensitivity and laser frequency stabilization
VL - 3270
ER -