A fully analytical toolbox for supercontinuum generation relying on scenarios without pulse splitting is presented. Furthermore, starting from the new insights provided by this formalism about the physical nature of direct and cascaded dispersive wave emission, a unified description of this radiation in both normal and anomalous dispersion regimes is derived. Previously unidentified physics of broadband spectra reported in earlier works is successfully explained on this basis. Finally, a foundry-compatible few-millimeters-long silicon waveguide allowing octave-spanning supercontinuum generation pumped at telecom wavelengths in the normal dispersion regime is designed, hence showcasing the potential of this new analytical approach.
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http://dx.doi.org/10.1364/OE.24.026629 | DOI Listing |
Sci Rep
January 2025
Laser Research Center, Vilnius University, Saulėtekio Avenue 10, LT-10223, Vilnius, Lithuania.
We present a comparative experimental study of supercontinuum generation in undoped scintillator crystals: bismuth germanate (BGO), yttrium orthosilicate (YSO), lutetium oxyorthosilicate (LSO), lutetium yttrium oxyorthosilicate (LYSO) and gadolinium gallium garnet (GGG), pumped by 180 fs fundamental harmonic pulses of an amplified Yb:KGW laser. In addition to these materials, experiments in yttrium aluminium garnet (YAG), potassium gadolinium tungstate (KGW) and lithium tantalate (LT) were performed under identical experimental settings (focusing geometry and sample thickness), which served for straightforward comparison of supercontinuum generation performances. The threshold and optimal (that produces optimized red-shifted spectral extent) pump pulse energies for supercontinuum generation were evaluated from detailed measurements of spectral broadening dynamics.
View Article and Find Full Text PDFSci Rep
January 2025
Photonics Laboratory, Tampere University, 33104, Tampere, Finland.
Supercontinuum generation in optical fiber involves complex nonlinear dynamics, making optimization challenging, and typically relying on trial-and-error or extensive numerical simulations. Machine learning and metaheuristic algorithms offer more efficient optimization approaches. We report here an experimental study of supercontinuum spectral shaping by tuning the phase of the input pulses, different optimization approaches including a genetic algorithm, particle swarm optimizer, and simulated annealing.
View Article and Find Full Text PDFWe demonstrate that amplitude modulation of a high-peak-power femtosecond laser pulse allows to change fundamentally the frequency-angular structure (FAS) of the supercontinuum formed during the filamentation in both molecular and atomic gases. Particularly, modulation with a 4-hole mask forms an inverted pattern of conical emission (CE) with its predominance in the Stokes wing of the pulse spectrum. We explain this phenomenon as a joint effect of self-phase modulation and temporal pulse splitting of interfering beamlets formed by the modulating mask.
View Article and Find Full Text PDFNanophotonics
August 2024
School of Information and Communications Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Nonlinear photonics has unveiled new avenues for applications in metrology, spectroscopy, and optical communications. Recently, there has been a surge of interest in integrated platforms, attributed to their fundamental benefits, including compatibility with complementary metal-oxide semiconductor (CMOS) processes, reduced power consumption, compactness, and cost-effectiveness. This paper provides a comprehensive review of the key nonlinear effects and material properties utilized in integrated platforms.
View Article and Find Full Text PDFSci Rep
December 2024
School of Information and Communications Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
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