Ultrafast laser stabilization by nonlinear absorption for enhanced-precision material processing.

Using ultrafast lasers, sub-diffraction features can be produced thanks to the threshold-based response of materials to the local beam fluence. In practice, Gaussian beams with peak fluence near the modification threshold lead to high-resolution. However, this conflicts with reliability as the process becomes increasingly sensitive to pulse-to-pulse energy fluctuations.

Simple and robust method for determination of laser fluence thresholds for material modifications: an extension of Liu's approach to imperfect beams.

The so-called D-squared or Liu's method is an extensively applied approach to determine the irradiation fluence thresholds for laser-induced damage or modification of materials. However, one of the assumptions behind the method is the use of an ideal spatial Gaussian beam that can lead in practice to significant errors depending on beam imperfections. In this work, we rigorously calculate the bias corrections required when applying the same method to Airy-disk like profiles.

Author Correction: Coherent scatter-controlled phase-change grating structures in silicon using femtosecond laser pulses.

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Coherent scatter-controlled phase-change grating structures in silicon using femtosecond laser pulses.

Periodic structures of alternating amorphous-crystalline fringes have been fabricated in silicon using repetitive femtosecond laser exposure (800 nm wavelength and 120 fs duration). The method is based on the interference of the incident laser light with far- and near-field scattered light, leading to local melting at the interference maxima, as demonstrated by femtosecond microscopy. Exploiting this strategy, lines of highly regular amorphous fringes can be written.

Three-Dimensional Self-Organization in Nanocomposite Layered Systems by Ultrafast Laser Pulses.

Controlling plasmonic systems with nanometer resolution in transparent films and their colors over large nonplanar areas is a key issue for spreading their use in various industrial fields. Using light to direct self-organization mechanisms provides high-speed and flexible processes to meet this challenge. Here, we describe a route for the laser-induced self-organization of metallic nanostructures in 3D.

Femtosecond laser-controlled self-assembly of amorphous-crystalline nanogratings in silicon.

Self-assembly (SA) of molecular units to form regular, periodic extended structures is a powerful bottom-up technique for nanopatterning, inspired by nature. SA can be triggered in all classes of solid materials, for instance, by femtosecond laser pulses leading to the formation of laser-induced periodic surface structures (LIPSS) with a period slightly shorter than the laser wavelength. This approach, though, typically involves considerable material ablation, which leads to an unwanted increase of the surface roughness.