| |
|
 |
NWLEC
RESEARCH
Key areas of research for NWLEC include:
- Micromachining
& surface texturing.
- Short
pulse laser-material interactions.
- Fiber laser sources for microprocessing.
- Micro
& nano particle generation.
- Optical Trapping.
- Deposition
of micro particles for part build & to add functionality
to surfaces.
- AFM/SPM nano machining/robotics
- Near Field nano patterning.
- Parallel laser processing with SLM technology
Selected published papers from NWLEC:
High throughput diffractive multi-beam femtosecond laser processing using a spatial light modulator
Applied Surface Science 255 (2008) 2284–2289
High throughput femtosecond laser processing is demonstrated by creating multiple beams using a spatial light modulator (SLM). The diffractive multi-beam patterns are modulated in real time by computer generated holograms (CGHs), which can be calculated by appropriate algorithms. An interactive LabVIEW program is adopted to generate the relevant CGHs. Optical efficiency at this stage is shown to be ~50% into first order beams and real time processing has been carried out at 50 Hz refresh rate. Results obtained demonstrate high precision surface micro-structuring on silicon and Ti6Al4V with throughput gain >1 order of magnitude.
Download
The influences of particle number on hot spots in strongly coupled metal nanoparticles chain
THE JOURNAL OF CHEMICAL PHYSICS 128, 094705 (2008)
In understanding of the hot spot phenomenon in single-molecule surface enhanced Raman scattering (SM-SERS), the electromagnetic field within the gaps of dimers (i.e., two particle systems) has attracted much interest as it provides significant field amplification over single isolated nanoparticles. In addition to the existing understanding of the dimer systems, we show in this paper that field enhancement within the gaps of a particle chain could maximize at a particle number N >2, due to the near-field coupled plasmon resonance of the chain. This particle number effect was theoretically observed for the gold (Au) nanoparticles chain but not for the silver (Ag) chain. We attribute the reason to the different behaviors of the dissipative damping of gold and silver in the visible wavelength range. The reported effect can be utilized to design effective gold substrate for SM-SERS applications.
Download
Generation and characterization of NiO nanoparticles by continuous wave fiber laser ablation in liquid
Journal of Nanoparticle Research
DOI 10.1007/s11051-008-9530-9
Pulsed laser ablation in liquid (PLAL) has been widely applied for the generation of nanoparticles (NPs). We report on the generation of NiO NPs using a high-power, high-brightness continuous wave (CW) fiber laser source at a wavelength of 1,070 nm. Characterization of such NPs in terms of size distribution, shape, chemical composition, and phase structure was carried out by transmission electron microscopy (TEM), high-resolution TEM equipped with energy-dispersive X-ray (EDX), and X-ray diffraction (XRD). The results revealed the formation of NiO NPs in water with an average size of 12.6 nm. The addition of anionic surfactant sodium dodecyl sulfate (SDS) reduced the size of NiO NPs down to 10.4 nm. The shape of the NPs was also affected by the SDS, showing the change of shapes from spherical domination in water to tetragonal with increased SDS.
Download
|
|
|
