The delayed optical nutation effect has been used to evaluate the longitudinal relaxation time (T 1) inside an acetylene-filled hollow-core photonic crystal fiber (HC-PCF) at room temperature. In this experiment, sequences of two short optical pulses of 30 ns and 15 ns in width, respectively, with the maximum peak power up to ∼2.5 W, were generated at a laser wavelength of 1530.37 nm, which corresponds to the acetylene ro-vibrational P9 absorption line. The gas pressure inside the 1 m-long HC-PCF varied in the range 0.1–1 Torr. Numerical simulations based on the optical Bloch equations allowed us to evaluate the longitudinal relaxation time as T 1 ∼ 9 ns , proving to be fundamentally limited by the transit-time broadening. Also, the obtained results revealed the influence of slow and fast molecules in the form of a non-exponential decay of the delayed-nutation signals. [ABSTRACT FROM AUTHOR]
Copyright of Journal of Applied Physics is the property of American Institute of Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)