Castello, Spain - Recognizing that production
of femtosecond lasers for micromachining is still slow and expensive, researchers
in the GROC Optics Group at James I University have developed an original
parallel-processing technique that could multiply their production capacity,
thus improving their performance, reducing the time and cost of
manufacturing, and optimizing the use of laser energy. Jesus Lancis, director
of the GROC Optics Group, highlights that the progress achieved "will
significantly improve the performance of this technology because it will
enable to process the material simultaneously in several locations and,
besides, without losing accuracy. Both facts are key to increase the
production rate of laser technology, thus lowering manufacturing costs and
allowing their gradual introduction into various sectors which used more
traditional production mechanisms hitherto."

The parallel-processing technique the researchers developed enables splitting
the laser beam into a series of multiple beams through what is called a "compensated
dispersion module." It has already proved its effectiveness to
simultaneously generate 52 blind holes measuring less than 5μm in diameter on
a stainless steel sample. "This research shows that we can increase
production speed by a factor of 52, or even 100, without losing quality, with
the change of system parameters," explains Gladys Minguez-Vega, a
researcher in the GROC Optics Group.

Pulsed femtosecond laser technology has provided a greater precision and
quality, says Mínguez-Vega. "These lasers are being used, for example,
in some surgical operations for less invasive, more localized, and precise
cuts, or in the development of micromachining in all types of materials,
including the biodegradable ones. With so short exposure times and with such
a high energetic charge, femtosecond lasers also prevent heat from spreading
beyond the point to which it is addressed, even allowing their use for
cutting explosives," she adds. The fact that energy is so concentrated
means that it has to be softened. "If you spent all this energy, you
will deposit so much energy that you would end up causing damage to the
material. To avoid this, we use some filters that reduce light to the right
energy," Mínguez-Vega explains. The matrix the researchers developed
allows splitting the beam and multiplying the points of light while reducing
the energy of each one of them. "Currently, for micromachining a piece with
a femtosecond laser, we have to move the laser or the material to scan it, so
production has to be performed point to point," she adds. The matrix
they developed divides beams and keeps their effectiveness, enabling
micromachining of dozens of different pieces simultaneously and multiplying
by hundred the speed of the system with the subsequent cost reduction.

The fact that energy is so concentrated means that it has to be softened. "If
you spent all this energy, you will deposit so much energy that you would end
up causing damage to the material. To avoid this, we use some filters that
reduce light to the right energy," Mínguez-Vega explains. The matrix the
researchers developed allows splitting the beam and multiplying the points of
light while reducing the energy of each one of them. "Currently, for
micromachining a piece with a femtosecond laser, we have to move the laser or
the material to scan it, so production has to be performed point to point,"
she adds. The matrix they developed divides beams and keeps their
effectiveness, enabling micromachining of dozens of different pieces
simultaneously and multiplying by hundred the speed of the system with the
subsequent cost reduction.



Full details of the work appear in the journal Optics Express; for more information,
http://dx.doi.org/10.1364/OE.21.031830.

발췌: http://www.industrial-lasers.com/articles/2014/12/parallel-processing-technique-enables-improved-femtosecond-laser-micromachining.html