Table of Contents
Principle of ultrafast laser systems
A ytterbium laser with thirtyfold compression by a gas-filled hollow-core fiber emits three-optical-cycle (10 fs) laser beam pulses, adding up to 318 W average power. The operating principle of such ultrafast laser systems is based on laser beam pulses of just a few optical cycles in length that interact with matter in unique ways. For instance, in the case of pushing beyond the research lab, such laser systems offer a crucial advantage to the industry.
Development of high-power few-cycle lasers
A group of scientists from Germany has developed an ultrafast laser that produces multimillijoule three-cycle laser beam pulses at a 318 W average power level. This advancement is significant and encourages progress in few-cycle laser technology, leading to new industrial applications, including the HR2 laser system. An innovative method has been employed; 300-fs-long laser beam pulses are directly compressed from a new, record-setting high-energy, high-power laser system to a few-cycle length.
30X compression and hollow-fiber technology
A 30X compression is required, and it has only recently become possible by “the introduction of stretched flexible gas-filled hollow-fiber technology, offering almost unrestricted-length scalability.” A multichannel ytterbium laser is considered to be the largest of its kind that enabling it to emit up to 10 mJ laser beam pulses at up to 1 kW average power and a 1.03 μm center wavelength applied as the light source.
Laser pulse compression using hollow optical fibers
Additionally, scientists employ a 6-m-long stretched flexible hollow optical fiber for the laser beam pulse compression. There is a self-phase modulation between the intense light and the gas atoms, which makes the spectrum broader since the pulses from the ultrafast laser system spread through the argon gas filling the hollow waveguide. It is possible to compress the laser beam pulses with a substantially broadened spectrum to a shorter duration due to the opportunity to reduce their spectral phase with a set of chirped mirrors.
Results and industrial applications
The ytterbium laser system has already been tested and demonstrated great results of producing multimillijoule 10 fs laser beam pulses at a 100 kHz repetition rate and an average power of 318 W, which is regarded as the highest average power ever achieved for a few-cycle fiber laser. This fiber laser technology promotes bringing high-power industry-grade laser systems into the few-cycle regime, enlarging new opportunities for industrial applications, for example, like highly parallelized materials processing. Also, the scientists confirm that this laser system favors completing the transformation of few-cycle technology from research devices to industrial tools.