Effect of Al concentration on optically pumped random lasing in Zn1−xAlxO (0 ≤ x ≤ 0.10) thin films fabricated via pulsed laser deposition technique. (April 2020) - Bharti, Gyan Prakash
Highlights: Lasing modes in Zn1−x Alx O (0 ≤ x ≤ 0.10) thin films fabricated via PLD technique. Nearly equidistant longitudinal lasing modes observed in the films. The lasing modes attributed to RL, FP and WGM cavities in the films. A maximum quality factor of 1004 achieved in x = 0.05 thin film sample. Abstract: Effect of Al content on the lasing emission of pulsed laser deposited nanostructured Zn1−x Alx O (0 ≤ x ≤ 0.10) thin films is reported in the present paper. The thin films were grown onto fused silica substrate employing 2nd harmonic of a Q-switched Nd:YAG laser (532 nm, 10 ns, 10 Hz). The Random lasing emission was observed in these films by pumping with 3rd harmonic of the Q-switched Nd:YAG laser (355 nm, 10 ns, 10 Hz). The longitudinal modes of nearly equal separation of ~3 nm were observed having FWHM in the range of 0.38–0.56 nm. The optical cavity length in these was found to be in the range of 7.3–8.1 μm. The lasing mechanism in the films having spherical particulates was due to the pure Random Lasing action where as that of containing the nano rods and nano wire was due to the formation of Fabry-Perot and Whispering Gallery Mode cavity together. The quality factor was observed to be highly influenced with Al content in the films and was found to be in the range of 691–1004. The maximum quality factor of 1004 was obtained for the thin film having x = 0.05 containing nanorods. The RL threshold was estimated to be ~3.2 × 10 2 MW/cm 2 .