Poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) spin-coated onto polyvinyl alcohol film as saturable absorber for generating Q-switched laser at 1.5 µm region

In this article, we proposed and demonstrated a Q-switched laser operating at a 1.5 µm region utilizing Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) spin-coated onto polyvinyl alcohol (PVA) thin film as a passive saturable absorber (SA). A stable Q-switched pulse train was successfully obtained to operate at 1563.3 nm with a 3-dB bandwidth of 1.24 nm while the highest pulse rate and the minimum pulse duration were recorded at 85.91 kHz, and 1.97 µs, respectively. The maximum average output power and pulse energy were measured to be 13.36 mW and 155.51 nJ respectively, with the highest peak power of 78.93 mW. The spin-coated PEDOT: PSS/PVA SA showed no deterioration sign even when the laser cavity was pumped at 225 mW power. This is the first time that PEDOT: PSS/PVA has been used as a SA to produce a stable Q-switched laser in 1.55 µm.