Maintenance measures for tangential flow filtration system
05,11,2026 157 views
【Instrument Network R&D News】Recently, researchers Fu Yuxi, Cao Huabao, and Liu Keyang from the National Key Laboratory of Ultrafast Optics Science and Technology have made new progress in the field of high repetition rate and high-energy ultrafast thin film lasers. Their research results have been published in Optics Letters.
High repetition rate and high-energy picosecond thin film laser can generate mid infrared few period femtosecond laser through frequency conversion process, which is known as the "third generation" femtosecond laser technology in academia and is an important driving source for producing high-performance attosecond light sources. Currently, commercial Yb: YAG thin film lasers all adopt the indirect cooling technology route of heat sink, and the core process of bonding thin film crystals with heat sinks is difficult and has a high threshold, which has long constrained the independent development of high-end ultrafast laser equipment in China.
In response to this challenge, the team innovatively adopted the direct liquid cooling hundred micron Yb: YAG thin film crystal technology path, breaking through the bottleneck of high-power and high-energy thin film laser head technology, and mastering the independent core process of the entire chain.
In the design of the laser head structure, the team integrated multiple thin films into the same laser head, and improved the heat extraction capability by increasing the number of coolant channels and coolant flow rate; Using a beam transmission gain medium to reduce beam distortion caused by material thermal deformation, flexible clamping greatly alleviates deformation caused by material thermal expansion, and stably ensures high-quality beam output; Simultaneously combining the multi stroke pump structure to fully absorb the semiconductor pump laser, achieving a compact structural design of the thin film laser head.
Based on the chirped pulse amplification (CPA) technology route, the team used a self-developed direct liquid cooled Yb: YAG thin film laser head to build a single laser head ring regeneration amplifier, achieving picosecond laser output with a repetition rate of 1 kHz, average power>200 W, and pulse energy>200 mJ. The output parameters are equivalent to those of the German TRUMPF company's Dira-200 product. This is currently the highest energy achieved internationally using a direct liquid cooled Yb: YAG thin film laser head at kHz repetition rate.
Liu Keyang introduced that "the 'indirect heat dissipation' used in commercial products is to 'weld' thin crystal sheets on the heat dissipation base, which requires extremely high requirements for 'welding'. Our technical route allows the coolant to flow quickly and stably directly on the surface of the crystal, and the heat generated is directly carried away by the flowing coolant, which not only improves the heat dissipation efficiency but also does not affect the beam quality, while maintaining the compact structure of the equipment and achieving parameter indicators that are on par with similar international products.
This achievement provides a new technological path for China's high-end ultrafast laser equipment to be independently controllable, and will provide solid technical support for the construction of major scientific and technological infrastructure in relevant countries.
Quote:Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences has made new progress in high repetition rate and high energy ultrafast thin slice lasers-Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences [Cited on: July 23, 2026]
