Abstract

Application of the phase memory of acetylene (${\mathrm{C}}_2{\mathrm{H}}_2$) vibrational-rotational transitions in the 1520–1540 nm wavelength range for a self-referencing homodyne detection of a sub-nanosecond optical phase modulation is reported. In the proposed configuration the collinearly propagating coherent dipole radiation of the excited molecule acts like a phase-locked reference wave (local oscillator) that enables transformation of the initial phase modulation into the intensity one. This technique does not need high light intensity and can operate in a linear range of the medium optical absorption. The linear optical phase demodulation (i.e., transformation of the phase-to-amplitude light modulation) is interpreted as an introduction of an additional phase shift to the carrier frequency component of the modulated signal in the maximum of the dispersion curve of a narrow optical absorption peak. It has been experimentally demonstrated with the bulk 10 cm long cuvette filled with low pressure ($\sim 2\mathrm{Torr}$) acetylene at room temperature. Effective demodulation of the milliwatt-scale incident laser wave of a single- and multi-mode structure is shown. As expected, the response to the fast ($<1\mathrm{ns}$) phase modulation was quadratic when the acetylene inhomogeneous Doppler-broadened ($\sim 500\mathrm{MHz}$) absorption line is excited in its center and was linearized by tuning at one of the absorption line sides. It is of a differentiating (high-pass) type with the cutoff frequency determined by the total spectral width of the utilized absorption line. Expected detection resolution is determined by the photon noise of the incident light intensity.

© 2019 Optical Society of America

Polarization hole burning and self-rotation of the polarization ellipse in an acetylene-filled hollow-core photonic crystal fiber

Nayeli Casillas, Serguei Stepanov, Manuel Ocegueda, and Eliseo Hernández
J. Opt. Soc. Am. B 38(1) 129-138 (2021)

High-resolution trace gas detection by sub-Doppler noise-immune cavity-enhanced optical heterodyne molecular spectrometry: application to detection of acetylene in human breath

Gang Zhao, Thomas Hausmaninger, Florian M. Schmidt, Weiguang Ma, and Ove Axner
Opt. Express 27(13) 17940-17953 (2019)

Synchronous in-phase and quadrature demodulation technique for resonant micro-optic gyroscope

Chuanbin Wu, Yi Lin, Xiaojun Jin, Huilian Ma, and Zhonghe Jin
Appl. Opt. 58(18) 5050-5056 (2019)

Absolute frequency measurement of an acetylene-stabilized laser at 1542 nm

Feng-Lei Hong, Atsushi Onae, Jie Jiang, Ruixiang Guo, Hajime Inaba, Kaoru Minoshima, Thomas R. Schibli, Hirokazu Matsumoto, and Ken’ichi Nakagawa
Opt. Lett. 28(23) 2324-2326 (2003)

Self-corrected frequency modulation spectroscopy immune to phase random and light intensity fluctuation

Jian Chen, Zhenhui Du, Tao Sun, Jinyi Li, and Yiwen Ma
Opt. Express 27(21) 30700-30709 (2019)