Canadian Team Develops First Visible Light Femtosecond Fiber Laser

Recently, researchers at Laval University in Canada announced the development of the first visible light femtosecond fiber laser, which is capable of generating bright femtosecond pulses in the visible light band and can be applied to materials processing and various biomedical applications.
Previously, generating visible pulses with durations in the femtosecond (10-15 seconds) range directly with fiber lasers was not possible, as it typically required complex and inherently inefficient setups.
Their new laser combines a lanthanide-doped fluoride fiber and a commercial blue diode-pumped laser to emit red light at 635 nm, achieving compressed pulses with a duration of 168 fs, a peak power of 0.73 kW and a repetition frequency of 137 MHz. The overall design has become more robust, compact and cost-effective and efficient due to the use of a commercial blue laser diode as the pumping source.
Rsamal Vallsame, head of the research team, said, "We have achieved an operational demonstration of a femtosecond fiber laser in the visible spectrum, thus paving the way for a new type of reliable, efficient and compact ultrafast laser."
According to the researchers, the recent availability of semiconductor laser sources capable of operating in the blue spectral band was key to the development of this highly efficient visible fiber laser. They also note that improvements in the fluoride fiber fabrication process were also critical to their ability to obtain lanthanide-doped fibers capable of achieving the performance required for highly efficient visible fiber lasers.
This type of laser is expected to be highly effective in more applications, including high-precision, high-quality biological tissue ablation and two-photon excitation microscopy, if it can be configured for higher power and energy in the future. Femtosecond laser pulses are also capable of cold ablation during material processing because it does not produce thermal effects, thus enabling cleaner cuts (than longer pulses)."
Next, the researchers hope to improve the technology by making the entire device completely monolithic, meaning that the individual fiber pigtail optics will all be directly connected together. This will reduce optical losses in the device, improve efficiency and make the laser more reliable, compact and robust. In addition, they are currently investigating different ways to increase the laser pulse energy, pulse duration and average power.