Femtosecond laser-induced black silicon: a dual application in photodetection and surface-enhanced Raman scattering.

A multifunctional structured silicon with enhanced optical and photoelectric properties has been processed by femtosecond (fs) laser in ambient air. The structured surface decorated with Au nanoparticles (NPs) exhibits excellent infrared absorption properties related to localized surface plasmon resonance (LSPR) coupled to microstructures. Over 75% absorption is achieved at 1550 nm, which is three orders of magnitude higher than that of unprocessed Si.

Direct Fabrication of Te-Doped Black Si with an Enhanced Photoelectric Performance by Femtosecond Laser Irradiation under Water.

Tellurium (Te)-doped black silicon (Si) with enhanced absorption and photoelectric performance over a broad wavelength range of 0.2-2.5 μm was obtained using femtosecond (fs) laser irradiation in liquid water.

Periodic Surface Structuring of Copper with Spherical and Cylindrical Lenses.

The use of a cylindrical lens in femtosecond laser surface structuring is receiving attention to improve the processing efficiency. Here, we investigate the structures produced on a copper target, in air, by exploiting both spherical and cylindrical lenses for beam focusing, aiming at elucidating similarities and differences of the two approaches. The morphological features of the surface structures generated by ≈180 fs laser pulses at 1030 nm over areas of 8 × 8 mm were analyzed.

Generation of Supra-Wavelength Grooves in Femtosecond Laser Surface Structuring of Silicon.

Extensive research work has been carried out on the generation and application of laser-induced periodic surface structures (LIPSS). LIPSS with a sub-wavelength period generated by femtosecond laser irradiation, generally indicated as ripples, have been extensively investigated. Instead, the other ordered surface structures characterized by a supra-wavelength period, indicated as grooves, have been much less studied.

Parameter optimization of a visibility LiDAR for sea-fog early warnings.

Sea fog represents a significant risk for safe navigation of sea vessels. Visibility LiDAR systems might offer a striking way to reduce the risks associated with sea fog, but they should be appropriately designed to provide a proper level of detection for reliable forewarning of sea fog. Here we analyze the performances of a visibility LiDAR system with the aim of achieving optimal detection operation.