The filament forming phenomenon of femtosecond laser pulses in transparent media is a hot topic in the field of strong field laser physics in recent years and has potential applications in many fields of research, such as high-order harmonics, strong field ionization, terahertz generation and remote sensing . When the femtosecond laser pulse is transmitted in the medium, it can cause the non-linear effect of the medium and cause the self-focusing effect of the laser beam in the medium. When the peak intensity of the pulse is increased to a certain extent, the ionization of the medium can be induced. Plasma channels have a defocusing effect on the laser beam. This self-focusing effect and the dynamic balance of the defocusing effect result in high intensity transmission of the laser beam over a long distance in the medium. In order to obtain longer laser filaments, different means are used to achieve laser filament length extension. In general, the length of a light beam is directly related to the energy of the input pulse. With a single pulse of energy greater than 5mJ laser input, the light has been extended to more than 2 meters in length. However, the use of femtosecond laser pulses of finite energy to extend the length of the filaments remains very limited. The ultra-fast laser research team led by Prof. Lu Peixiang from Wuhan National Laboratory of Optoelectronics has put forward a scheme that can effectively increase the length of the filament for the problem of filament formation under the condition of limited pulse energy. In this scenario, the initial collimated laser beam is input to a spatial phase modulator, and the collimated beam is converted into a multi-focal beam by modulating its amplitude and phase in space. With this modulation, the transmission characteristics of the laser beam are tightly controlled and focused over several different distances. The pulse energy is effectively distributed in different positions of the optical fiber, thereby realizing the extension of the plasma channel. Simulation calculations show that with only 2mJ pulses of energy, a multifocal beam produces a filament that has nearly doubled in length to nearly 1 meter compared to the common single focal length scheme. By adjusting the spatial phase modulator, the length and distance of the lightwaves can be easily changed. In the meantime, the growing plasma channel will also lead to the accumulation of self-phase modulation effects, resulting in a larger bandwidth supercontinuum output. The research results provide an effective tool for the research of ultrafast optics and strong field physics. The research results "Extending plasma channel of filamentation with a multi-focal-length beam", 22 February 2016, published in Optics Express 24, 4, 4029-4041 ( 2016). Figure (a) peak intensity of multi-focal length light beam (b) plasma concentration and flux (c) changes in the transmission process Waste water Enzymes,enzymes in waste water,sewage treatment plant enzymes Sunson Industry Group Co., Ltd , https://www.sunsonchinaenzymes.com