Dynamic Multifocus Laser Writing with Acousto‐Optofluidics

Abstract

Laser writing of materials is normally performed by the sequential scanning of a single focused beam across a sample. This process is time‐consuming and it can severely limit the throughput of laser systems in key applications such as surgery, microelectronics, or manufacturing. A parallelization strategy based on ultrasound waves in a liquid to diffract light into multiple beamlets is reported. Adjusting amplitude, frequency, or phase of ultrasound allows tunable multifocus distributions with sub‐microsecond control. When combined with sample translation, the dynamic splitting of light leads to high‐throughput laser processing, as demonstrated by locally modifying the morphological and wettability properties of metals, polymers, and ceramics. The results illustrate how acousto‐optofluidic systems are universal tools for fast multifocus generation, with potential impact in fields such as imaging or optical trapping.

Nanopatterning with Photonic Nanojets: Review and Perspectives in Biomedical Research

“…Furthermore, the possibility of exploiting photonic nanojets directly for optical sensing or surgery may further expand and complete their portfolio of biomedical applications [ 143 , 144 ]. As photonic nanobeams with novel features are engineered—photonic nanohook is a quite recent example [ 145 ]-and innovative illumination methods [ 146 , 147 ] are implemented to enhance the light–matter interaction, interesting applications for research and industry will continue to emerge.…”

Acoustically-shaped laser: a machining tool for Industry 4.0

“…where 0 is the static refractive index of the liquid and Δn the peak of the induced variations. The latter depends on both the amplitude and frequency of the driving signals [32], [33]. Based on Equation 2, we can anticipate that the cavity behaves as an oscillating periodic grating capable of diffracting the incident light.…”

“…Specifically, Figure 2 shows the effects of the AOF cavity on a Gaussian laser beam when combined with a telescope. In the focal plane of the first lens, the oscillating grating diffracts the laser beam into multiple beamlets [32]. The number, spacing, and intensity of each diffracted spot can be controlled by properly adjusting the driving parameters, such as amplitude, frequency, and the phase of the signals applied to the piezoelectric plates.…”

“…Notably, the generated pattern can be controlled with the same parameters that control the beamlets. The phase, in particular, allows ultra-fast pattern selection when a pulsed laser with a duration much smaller than the temporal period of the driving signals is used [32], [33]. In this case, the laser pulse interacts with an instantaneous refractive index profile (see Equation 2) that can be selected by delaying the arrival of the laser with respect to the temporal period of the driving signal and, thus, with nanosecond resolution.…”

“…We recently proved that rapid (in the sub-microsecond timescale) both-beam parallelisation (up to 35 beams) and the generation of complex and tuneable light patterns can be achieved through the interaction of laser and acoustic waves in a liquid [32], [33]. Our technology, acousto-optofluidics (AOF), enables high-throughput material processing without suffering from the problems (damage, pixellation, and speed) of conventional methods.…”