Employing high-yield production of layered materials by liquid-phase exfoliation, molybdenum disulfide (MoS2) dispersions with large populations of single and few layers were prepared. Electron microscopy verified the high quality of the two-dimensional MoS2 nanostructures. Atomic force microscopy analysis revealed that ~39% of the MoS2 flakes had thicknesses of less than 5 nm. Linewidth and frequency difference of the E(1)2g and A1g Raman modes confirmed the effective reduction of flake thicknesses from the bulk MoS2 to the dispersions. Ultrafast nonlinear optical (NLO) properties were investigated using an open-aperture Z-scan technique. All experiments were performed using 100 fs pulses at 800 nm from a mode-locked Ti:sapphire laser. The MoS2 nanosheets exhibited significant saturable absorption (SA) for the femtosecond pulses, resulting in the third-order NLO susceptibility Imχ((3)) ~ 10(-15) esu, figure of merit ~10(-15) esu cm, and free-carrier absorption cross section ~10(-17) cm(2). Induced free carrier density and the relaxation time were estimated to be ~10(16) cm(-3) and ~30 fs, respectively. At the same excitation condition, the MoS2 dispersions show better SA response than the graphene dispersions.

Intense short-wavelength photoluminescence (PL) observed at room temperature from thermal SiO2 films co-implanted with Si and C is reported. A flat Si profile was first implanted, followed by 1100 °C annealing for 60 min. C ions were subsequently used to be implanted into the same depth region. PL was observed from the as-implanted samples with and without annealing. The PL intensity increases with annealing temperature. Comparing the PL spectra and the PL dynamics of the C-implanted, annealed, Si-implanted (CIASI) SiO2 films with those from Si- and C-implanted SiO2 films suggests that the interaction of Si and C in SiO2 films plays an important role in the luminescence in CIASI SiO2 films.

Highly transparent Tm:YAG ceramic was fabricated by a solid‐state reaction and vacuum sintering. The optical properties, the microstructure, and the laser performance of the Tm:YAG ceramic were investigated. A Tm:YAG ceramic with an average grain size of ∼10 μm was obtained by sintering at 1750°C for 10 h. The in‐line transmittance was 84.0% at 2015 nm. The absorption coefficients at 681 and 785 nm were 8.23 and 3.27 cm−1, respectively. The grain boundaries were clean and no secondary phase was observed. The 6 at.% Tm:YAG ceramic slab (1.2 mm × 5 mm × 6 mm) was end‐pumped by a laser diode at 792 nm, and the maximum output power of 4.5 W was obtained with a slope efficiency of 20.5% at 2015 nm.

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