Using femtosecond laser-induced forward transfer techniques we have fabricated gold dots and nanoparticles on glass substrates, as well as nanobumps on gold thin film. The surface morphologies of these structures with different laser fluences and film thicknesses are investigated. We also study the focusing and defocusing properties of the nanofence-an arranged nanobump pattern-by the total-internal reflection microscope. Observations reveal that surface plasmon waves can be highly directed and focused via this nanofence pattern. Results are in good agreement with the simulation results using the finite-element method and demonstrate the potential applications of these nanophotonic devices. Furthermore, we utilize high laser energy to fabricate plasmonic waveguides, and also succeed in transferring the waveguides to another substrate. The attenuation rates of the light propagating in the waveguides are observed to achieve 0.31 dB μm(-1) and 0.48 dB μm(-1) on the target and receiver sides, respectively.
Micromodification in bulk undoped polymethylmethacrylate (PMMA) by single focused (numerical aperture (NA) = 0.25), 1030-nm 250-fs laser pump pulses was explored by pump self-transmittance; optical, 3D-scanning confocal photoluminescence (PL); Raman micro-spectroscopy; and optical polarimetric and interferometric microscopy. Starting from the threshold pulse energy = 0.
Femtosecond laser inscription in a ytterbium-doped silver-containing phosphate glass is demonstrated by achieving 3D highly localized laser-induced silver photochemistry. The produced fluorescent silver nanoclusters lead to high optical contrast in the visible range, showing that the coinsertion of Yb ions is not detrimental to the silver-based photochemistry. We demonstrate efficient energy transfer from these silver nanoclusters to the rare-earth Yb ions, leading to near-IR background-free fluorescence emission.
In this Letter, over-correction of spherical aberration is used to counteract nonlinear effects such as Kerr self-focusing and plasma effects, resulting in more spherical and small-sized femtosecond laser-inscribed voxels within nonlinear materials. By strategically redirecting marginal focusing rays toward the beginning of the laser modification zone, the induced plasma prevents any rays from causing a structural modification beyond this zone, irrespective of any focus elongation caused by nonlinear effects. The method has been effectively validated across a range of materials, including ZnS, ZnSe, BIG, GeS, and SiO.
High-efficiency and high-quality sterilization technologies for medical materials can significantly reduce iatrogenic infection. This study investigates the synergistic effects of laser-induced periodic surface structures (LIPSS) and ultrasonic cleaning on the removal of bacteria from medical material surfaces. We specifically examined how ultrasonic parameters and structural defects in LIPSS impact the effectiveness of bacterial removal.
Modern photonic devices demand low-cost, scalable methods for creating periodic patterns over diverse surfaces including nonplanar and tipped ones, the examples of which can be readily found in fiber optics. Laser-induced periodic surface structures (LIPSS) offer an attractive route for fabricating such patterns in a single-step straightforward procedure, where the temporal and spatial locality of the self-interference effects ensure robustness against variations of the laser processing parameters. In this work, we show the LIPSS-assisted oxidation of thin titanium films by near-IR femtosecond laser pulses as a promising technology for the production of regular gratings consisting of rutile ridges.
