English

An efficient femtosecond pulse amplification technique for extracting the maximum stored energy in fiber laser amplifiers

189
2024-11-13 11:55:15
See translation

The well-known journal Optica published a paper in November 2024 titled "Near complete extraction of maximum stored energy from large core fibers using coherent pulse stacking amplification of femtosecond pulses"The authors of the paper were the University of Michigan, Lawrence Berkeley National Laboratory, Peking University, and the German Institute of Synchrotron Radiation.

The specific technique is to use a cascaded "GTI" (Gire Tounois interferometer) method to synthesize 81 amplified pulses together in the time domain. The technical difficulty that needs to be overcome is to control the phase and amplitude of each pulse to achieve coherent synthesis. The core femtosecond light source is a 1 GHz repetition rate femtosecond fiber laser, developed by Professor Zhang Zhigang's group at the School of Electronics, Peking University.

The author of the paper has demonstrated using the aforementioned techniques that, with a continuous pump of 100 W and a repetition rate of 2 kHz, nearly 10 mJ of amplified pulse energy can be extracted, far exceeding the energy output of conventional large mode area fiber amplifiers, which can reach less than 1 mJ. The extraction efficiency is close to 90%.

This efficient time-domain pulse synthesis technique can greatly improve the efficiency of pulse synthesis and reduce the number of amplifiers used for spatial synthesis.

Although the repetition rate and pulse energy obtained from this experiment are not yet high, this technology demonstrates the potential to generate femtosecond strong laser pulses with Joule level pulse energy and repetition rates above 10 kHz. It may provide a light source for studying strong field physics and particle accelerators under extreme conditions, as well as for generating secondary radiation.

Figure 1 shows the efficiency of pulse energy extraction in a fiber amplifier independent of core diameter under nonlinear confinement. Figure 1 indicates that the pulse extraction efficiency can only approach 100% of the amplifier's stored energy when the pulse is broadened to 100 ns


Figure 2 shows a schematic diagram of a composite GTI cavity, where 81 incident laser pulses are coherently superimposed in four large loop cavities to form 9 pulses; Then coherently superimpose them into one pulse in four small cavities


Figure 3: Photo of the Composite GTI Chamber Experimental Device


Figure 4 shows the pulse waveform and spectrum of the coherent synthesized pulse with an energy of 3 mJ and a width of 313 fs

Source: Yangtze River Delta Laser Alliance

Related Recommendations
  • The acoustooptic modulation of gigawatt level laser pulses in ambient air can be applied to other optical components such as lenses and waveguides

    An interdisciplinary research group, including the German synchrotron radiation accelerator DESY and the Helmholtz Institute in Jena, Germany, reported that invisible gratings made of air not only are not damaged by lasers, but also maintain the original quality of the beam.The relevant research has been published in Nature Photonics under the title of "Acousto opt modulation of gigawatt scale las...

    2023-10-12
    See translation
  • Research Progress: Extreme Ultraviolet Photolithography

    Recently, the semiconductor industry has adopted Extreme Ultraviolet Lithography (EUVL) technology. This cutting-edge photolithography technology is used for the continuous miniaturization of semiconductor devices to comply with Moore's Law. Extreme ultraviolet lithography (EUVL) has become a key technology that utilizes shorter wavelengths to achieve nanoscale feature sizes with higher accuracy a...

    2024-12-09
    See translation
  • A new approach to 3D printing has been published in a Nature journal

    In the last century, the improvement of mechanical properties of structural metals was mainly achieved through the creation of increasingly complex chemical compositions. The complexity of this ingredient increases costs, creates supply fragility, and makes recycling more complex.As a relatively new metal processing technology, metal 3D printing provides the possibility to re-examine and simplify ...

    2024-11-29
    See translation
  • Lumibird signs a 20 million euro contract to provide laser rangefinders for airborne defense applications

    Recently, European laser technology leader Lumibird announced the signing of a major contract to provide laser rangefinders for airborne defense applications.The contract is worth approximately 20 million euros, adding to Lumibird's existing business in laser rangefinders. It covers the supply of over 100 laser rangefinders over a three-year period starting from the third quarter of 2024, as well ...

    2023-10-01
    See translation
  • LIS Technologies closes $11.88 million seed round of financing

    On August 19th, local time, LIS Technologies, a U.S.-based developer of laser uranium enrichment technology, announced the latest closing of an $11.88 million seed round of financing. According to reports, LIS Technologies is a company focused on developing advanced laser technology and is the only U.S.-based laser uranium enrichment company to hold a homegrown patent. The round attracted a numb...

    2024-08-22
    See translation