Thin films of hydrogenated amorphous silicon were grown on cover glasses by PECVD in an Oxford PlasmaLab System 100. The thickness of the films and their linear optical properties were characterized by J.A. Woollam Co. Spectroscopic Ellipsometer M-2000D. The follow-up procedure was to spin coat the negative tone ma-N 2403 electron-beam resist over the film, and expose the resist using an electron-beam lithography system (Raith 150). The exposed film was developed and brought to the reactive ion etching facility. We performed conventional apertureless z-scan and I-scan measurements. A train of femtosecond laser pulses form a Coherent Micra 5 laser with an output mean power of 250 mW passed through a precompressor for a negative chirp. A thin-film nanoparticle polarizer (ThorLabs LPVIS050) and a Glan laser-grade polarizer were used to adjust the fluence values in the range of 0.1–10 mJ/cm2. For the pump-probe measurements, a train of femtosecond laser pulses form the laser passed through a pre-compressor for a negative chirp. The pulses were split into two; the resulting mean power values of pump and probe beams at the sample site were approximately 40 mW and 1.5 mW, respectively. The pulses were measured to have 45 fs intensity autocorrelation FHWM duration, and a spectral FWHM width of 19 nm, resulting in a time-bandwidth product of 0.4. Focusing through a silica lens pair achieved waists of roughly 30 μm in diameter, resulting in modest pump fluence values of approximately 30 μJ/cm2, a pump pulse energy of 0.25 nJ, and per-disk deposited energy of 13 fJ. The third-harmonic generation experiment description can be found as the supplementary information of the following publication: http://pubs.acs.org/doi/abs/10.1021/nl503029j
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