| Biography | |
|---|---|
 Prof. Zefeng Wang National University of Defense Technology (NUDT), China |
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| Title: Mid-infrared fiber gas lasers | |
| Abstract: Fiber lasers have wide potential applications, and are increasingly replacing traditional solid state and gas lasers in many applications due to their compactness, high efficiencies, excellent beam qualities and convenient heat management. However, due to the low damage threshold, solid-core fiber lasers lack the ability to provide the same power levels as conventional gas lasers, which can reach MW levels in chemical gas lasers; Because of nonlinear effects, the spectral linewidth of light generated in silica fibers will broaden at high powers; As the number of rare earth materials is limited, only certain laser wavelengths are available; Due to the strong infrared absorption of silica fibers, it is difficult to obtain laser wavelength beyond 3 μm. Gas lasers has been demonstrated to be an effective method to obtain high-power narrow-linewidth mid-infrared lasers. In traditional gas cells the effective interaction length is very short and the system can be bulky and cumbersome, limiting the applications of these lasers. The advent of anti-resonance hollow-core fibers and their properties of long effective interaction length, high optical confinement, and the possibility of control of the effective gain spectrum make it possible to develop a novel type of laser, named fiber gas lasers (FGLs), which combines the advantages of both fiber and gas lasers. By properly designing the transmission bands of hollow-core fibers, selecting active gases and pump sources, FGLs can potentially provide a wide emission wavelength range in the mid-infrared. Owing to the nature of transitions in atomic and molecular gases, FGLs are spectrally narrow even without additional linewidth limiting measures. We have demonstrated efficient 2.8 μm, 3 μm, 4 μm and 4.3 μm FGLs using hollow-core fibers filled with different gases. Our work provides a potential simple and efficient way for high-power, narrow-linewidth mid-infrared fiber lasers. Acknowledgement This work was supported by Outstanding Youth Science Fund Project of Hunan Province Natural Science Foundation (2019JJ20023) and National Natural Science Foundation of China (NSFC) (11974427). | |
| Biography: Zefeng Wang received Doctor Degree in Optical Engineering from the NUDT in June 2008. He visited Bath University in UK from October 2012 to July 2014. He is currently a professor with College of Advanced Interdisciplinary Studies, NUDT. He has published more than 100 papers as first author or corresponding author, of which 60 are included in SCI. He has been authorized 14 invention patents as first inventor. His research interests cover mainly high-power fiber lasers, gas lasers by hollow-core fibers, fiber gratings fabrications and applications. | |
