Relaxation Oscillation with Picosecond Spikes in a Conjugated Polymer Laser

Wafa Musa Mujamammi; Saradh Prasad; Mohamad S AlSalhi; Vadivel Masilamani

doi:10.3390/polym8100364

Relaxation Oscillation with Picosecond Spikes in a Conjugated Polymer Laser

Polymers (Basel). 2016 Oct 14;8(10):364. doi: 10.3390/polym8100364.

Authors

Wafa Musa Mujamammi¹, Saradh Prasad^{2

3}, Mohamad S AlSalhi^{4

5}, Vadivel Masilamani^{6

7}

Affiliations

¹ Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia. walmujammi@ksu.edu.sa.
² Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia. srajendra@ksu.edu.sa.
³ Research Chair on Laser Diagnosis of Cancers, College of Science, King Saud University, Riyadh 11451, Saudi Arabia. srajendra@ksu.edu.sa.
⁴ Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia. malsalhi@ksu.edu.sa.
⁵ Research Chair on Laser Diagnosis of Cancers, College of Science, King Saud University, Riyadh 11451, Saudi Arabia. malsalhi@ksu.edu.sa.
⁶ Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia. mvadivel@ksu.edu.sa.
⁷ Research Chair on Laser Diagnosis of Cancers, College of Science, King Saud University, Riyadh 11451, Saudi Arabia. mvadivel@ksu.edu.sa.

Abstract

Optically pumped conjugated polymer lasers are good competitors for dye lasers, often complementing and occasionally replacing them. This new type of laser material has broad bandwidths and high optical gains comparable to conventional laser dyes. Since the Stokes' shift is unusually large, the conjugated polymer has a potential for high power laser action, facilitated by high concentration. This paper reports the results of a new conjugated polymer, the poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}](PFO-co-MEH-PPV) material, working in the green region. Also discussed are the spectral and temporal features of the amplified spontaneous emissions (ASE) from the conjugated polymer PFO-co-MEH-PPV in a few solvents. When pumped by the third harmonic of the Nd:YAG laser of 10 ns pulse width, the time-resolved spectra of the ASE show relaxation oscillations and spikes of 600 ps pulses. To the best of our knowledge, this is the first report on relaxation oscillations in conjugated-polymer lasers.

Keywords: amplified spontaneous emission spectra (ASE); conjugated polymer (PFO-co-MEH-PPV); green laser; picoseconds spikes; relaxation oscillations.