For silicon, relaxation processes are dependent on the Ibrutinib supplier electron-phonon coupling constant (1 ps for silicon); therefore, a dramatic increase in temperature occurs after this point. The temperatures experienced by the irradiated target area during fs-PLD are typically above that of the boiling point, depending on the fluence of the laser [2]. For a silicon target, there are certain thresholds associated with ablation from its surface. With an 800-nm wavelength and 80-fs pulse duration, Bulgakov et al. [8] demonstrated the emission of clusters (ionic and neutral) as well as singular ions and atoms (collectively, these shall henceforth be referred to as clusters) being emitted from a

silicon target surface occurring at fluences as low as 100 mJ cm −2 and increasing in yield with fluence. As the fluence is increased still further, a second threshold is reached, where nanoparticles

of the target material begin to be ablated in tandem with the initially emitted clusters. The exact mechanism for the ejection of nanoparticles and microparticles from the target material is still under debate by many [1–5, 8]. When compared to standard fabrication techniques such as chemical vapour deposition (CVD), a common technique for the fabrication of thin film and multilayered devices, fs-PLD offers a huge amount of versatility. CVD is often limited by the reactants used which are also commonly found to be either toxic, highly R428 flammable or both. fs-PLD is not limited by the type of material either as ablation occurs via nonlinear absorption of the laser pulses; therefore, target materials as varied as glass, polymer, semiconductor, metal, etc. can be adopted to grow multilayered nanoparticulate thin

films. It is important to note that target materials can also comprise Cell press any number of different elements, and all will be ablated without overly complex control of the experimental parameters, beyond that described earlier. As described earlier, fs-PLD has the potential to be an extremely effective nanofabrication technique and therefore is worthy of exploration for its ability to fabricate solid state nanoparticulate thin films. Here, some of the defining parameters of fs-PLD are explored so as to fabricate high-quality devices with a smooth continuous deposited layer which is currently lacking in the literature. The optimised fabrication processes presented here has been utilised for Tm 3+-doped Si with successful room temperature emission from the 3F4 →3H6[9]. The use of silicon as an optical host material is also very attractive due to its large optical window in the infrared (IR) between 2 and 7 μm. This IR region holds particular interest for identifying the molecular fingerprints of certain molecules and can also be utilised for optical communications.