R.  Kanavvade, Kumar, A., Pawar, D., Vairagi, K., Late, D., Sarkar, S., Sinha, R. K., and Mondal, S., ?Negative axicon tip-based fiber optic interferometer cavity sensor for volatile gas sensing?, Optics Express, vol. 27, no. 5, pp. 7277-7290, 2019.