Phase-shift Cavity Ring Down Spectroscopy Set-up for NO2 Sensing : Design and Fabrication

  • Cherry Dhiman Dept. of Physics, Jamia Millia Islamia, New Delhi
  • Mohd. Shahid Khan Dept. of Physics, Jamia Millia Islamia, New Delhi
  • M.N. Reddy Laser Science and Technology Centre, Delhi
Keywords: Phase-shift cavity ring down spectroscopy (PS-CRDS), high reflectivity, laser diode, broadband

Abstract

An indigenously designed cavity ring down spectroscopy cell of 80 cm length of mild steel material was fabricated by attaching two 1″ diameter high reflecting concave mirrors with reflectivity 99.997 % at 405 nm and radius of curvature was 1 m in specially designed mirror holding assemblies to the cell at two ends. Fine alignment of the resonator is facilitated with three tip-tilt adjusting screws to the mirror-mounting plate assembly. The PS-CRDS experimental set-up is evaluated by measuring the phase shift values corresponding to the absorption of NO2 gas filled at low pressures in the cell. The limit of detection of pure NO2 using the set-up under given conditions of Ar @ 50 mbar is estimated to be 1.50 × 1011 cm-3 and @ 60 mbar as 2 × 1011 cm-3.

Defence Science Journal, Vol. 65, No. 1, January 2015, pp.25-30, DOI:http://dx.doi.org/10.14429/dsj.65.7790

Author Biographies

Cherry Dhiman, Dept. of Physics, Jamia Millia Islamia, New Delhi
Ms Cherry Dhiman received her BSc (H) Physics from Deen Dayal Upadhayaya College, Delhi University, and MSc (Physics) from Punjabi University, Patiala. She is currently pursuing her PhD from Jamia Milia Islamia, New Delhi. She has worked as a project assistant on a DRDO funded project on ‘Detection of traces of toxic gases/Explosives using cavity ring down laser spectroscopy’ at Jamia Milia Islamia (JMI), New Delhi.
Mohd. Shahid Khan, Dept. of Physics, Jamia Millia Islamia, New Delhi
Dr Mohd. Shahid Khan did his MSc Physics (Material Science) from Jamia Millia Islamia, New Delhi, in 1992. He completed his PhD (Physics) from JMI in 2002. He has been teaching Physics at JMI since 2004 and is presently working as Assistant Professor. His areas of research are laser spectroscopy, non-linear optics and computational molecular and nanoscience. He has authored 40 research publications.
M.N. Reddy, Laser Science and Technology Centre, Delhi
Dr M.N. Reddy is Scientist ‘G’ and Divisional Head of Advanced S&T and Photonics Division at LASTEC, Delhi. He has done his MSc and MPhil in Physics from Central University of Hyderabad, Hyderabad, and PhD in Laser High Resolution Spectroscopy of Rydberg Atoms from IIT, Kanpur. His present R&D activities include development of laser based sensors for stand-off detection of explosives and mines and high power fibre lasers for directed energy systems.
Published
2015-02-26
How to Cite
Dhiman, C., Khan, M., & Reddy, M. (2015). Phase-shift Cavity Ring Down Spectroscopy Set-up for NO2 Sensing : Design and Fabrication. Defence Science Journal, 65(1), 25-30. https://doi.org/10.14429/dsj.65.7790
Section
Chemical Science & Technology