Abstract
We investigate experimentally the local intensity control in the visible region of the supercontinuum (SC) generated from femtosecond laser filamentation in fused silica by using pulse shaping technology. Based on the genetic algorithm, we show that a distinct spectral hump at any preset wavelength can be formed in the blue-side extension. The local intensity control in the SC could improve the abilities of the SC applications.
Highlights
Since spectral broadening by focusing a high-power picosecond laser pulse into crystals and glasses was discovered by Alfano and Shapiro, supercontinuum (SC) source has attracted widespread attention due to the spectral range’s spectacular ability to span from ultraviolet to mid-infrared [1,2]
The broadband SC source has found a variety of applications, such as spectroscopy [3,4], fluorescence microscopy [5], optical coherence tomography [6,7], and chemical sensing [8]
Chen et al presented a systematical investigation on the laser polarization effect on the SC generation from femtosecond laser filamentation in air
Summary
Since spectral broadening by focusing a high-power picosecond laser pulse into crystals and glasses was discovered by Alfano and Shapiro, supercontinuum (SC) source has attracted widespread attention due to the spectral range’s spectacular ability to span from ultraviolet to mid-infrared [1,2]. Numerous studies have been performed to optimize filamentation and SC, in order to achieve high-power, ultra-broadband, and controllable SC spectrum. A multi-octave SC with a wide wavelength coverage has been obtained via filamentation generation by the near- and mid-infrared ultrashort-pulse laser in the range of anomalous group velocity dispersion of wide bandgap dielectric media, such as YAG, sapphire, and fluoride crystal, or in various types of glasses [17]. Chen et al presented a systematical investigation on the laser polarization effect on the SC generation from femtosecond laser filamentation in air They found that the circular polarization filamenting pulse is favorable for the intensity enhancement of the SC generation in the short wavelength range, and the linear polarization pulse is favorable for the spectral broadening [35]. The results show that the spectral hump in the visible region of SC can be controlled and arbitrarily shifted
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