In this work we present a promising method for fabrication of conductive tracks on paper based substrates by laser assisted reduction of Graphene Oxide (GO). Printed electronics on paper based substrates is be coming more popular due to lower cost and recyclability. Fabrication of conductive tracks is of great importance where metal, carbon and polymer inks are commonly used. An emerging option is reduced graphene oxide (r-GO), which can be a good conductor. Here we have evaluated reduction of GO by using a 532 nm laser source, showing promising results with a decrease of sheet resistance from >100 M Ω/Sqr for unreduced GO down to 126 Ω/Sqr. without any observable damage to the paper substrates.
In this work we have investigated the use of laser sintering of different ink-jet printed nano-particle links (NPIs) on paper substrates. Laser sintering is shown to offer a fast and non-destructive way to produce paper based printed electronics. A continuous wave fiber laser source at 1064 nm is used and evaluated in combination with a galvo-scanning mirror system. A conductivity in order of 2.16 <sub>*</sub> 10<sup>7</sup> S/m is reached for the silver NPI structures corresponding to nearly 35 % conductivity compared to that of bulk silver and this is achieved without any observable damage to the paper substrate.
In this work we present a compact, nanosecond pulsed, single frequency, single stage Yb-doped fiber amplifier by using an overall fiber core diameter of 20 μm. The key component is a custom made, compact, ultra-low noise, single frequency ring-cavity solid state laser (SSL) at 1064 nm used as a master oscillator. The SSL can be designed to provide nanosecond pulses with pulse energies in the sub-mJ range. Our ultimate goal is to develop a compact linearly polarized, single frequency, nanosecond pulsed laser source in an all-fiber format. Short (less than 1m), highly Yb-doped fibers have been used in order to suppress non-linear effects.
A fiber laser operating at 1.94μm in pulsed regime has been developed in a MOPA configuration. The seed consists of a custom-developed board hosting a laser diode, whose current is modulated to achieve the desired pulse shape, duration and repetition rate. The pulses are amplified through a thulium-doped fiber amplifier pumped at 793 nm. The design of the amplifier stage has been performed by dynamic simulation of a rate-equations model and compared to the experimental measurements. Simulations and experimental measurements have exhibited comparable results, devising the realization of an effective pulsed laser system whose parameters can be easily tuned through the seed.