Real time revealing relaxation dynamics of ultrafast mode-locked lasers

Xian, Tianhao; Wang, Wenchao; Zhan, Li

doi:10.1103/physrevresearch.4.013202

Cited by 9 publications

(1 citation statement)

References 47 publications

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“…4(a). Therefore, this effect can change the envelope of the pulse, causing the fluorescent pulse to move forward compared to the pump pulse as the green curve shows, but it does not change the phase velocity [24] . After the pulse energy is further increased above the threshold, the pulse width of the RL becomes narrower.…”

Section: Resultsmentioning

confidence: 99%

Picosecond gain-switched polymer fiber random lasers

Du,

Gao,

Zhang

et al. 2024

中国光学快报

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Random lasers are a type of lasers that lack typical resonator structures, offering benefits such as easy integration, low cost, and low spatial coherence. These features make them popular for speckle-free imaging and random number generation. However, due to their high threshold and phase instability, the production of picosecond random lasers has still been a challenge. In this work, we have developed three dyes incorporating polymer optical fibers doped with various scattering nanoparticles to produce short-pulsed random fiber lasers. Notably, stable picosecond random laser emission lasting 600 ps is observed at a low pump energy of 50 μJ, indicating the gain-switching mechanism. Population inversion and gain undergo an abrupt surge as the intensity of the continuously pumped light nears the threshold level. When the intensity of the continuously pumped light reaches a specific value, the number of inversion populations in the "scattering cavity" surpasses the threshold rapidly. Simulation results based on a model that considers power-dependent gain saturation confirmed the above phenomenon. This research helps expand the understanding of the dynamics behind random medium-stimulated emission in random lasers and opens up possibilities for mode locking in these systems.

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Section: Resultsmentioning

confidence: 99%

Picosecond gain-switched polymer fiber random lasers

Du,

Gao,

Zhang

et al. 2024

中国光学快报

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CW‐Seeded Parametric Combs with Quantum‐Limited Phase Noise

Wang,

Shi,

Steinmeyer

et al. 2024

Laser & Photonics Reviews

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Optical frequency combs have revolutionized frequency metrology and spectroscopic measurements, enabling the most precise measurements of all physical quantities. However, precision frequency metrology heavily relies on mode‐locked laser combs, which are only directly available for a few selected near‐infrared wavelength ranges. Recently, a strong tendency emerged for combs in the mid‐infrared molecular fingerprint region. To this end, several methods for wavelength conversion have been proposed and demonstrated, which nevertheless cost a degradation of coherence properties. Here a first approach is presented toward measuring resulting phase noise fluctuations, exploiting the temporal resolution of the dispersive temporal interferometry (DTI) technique for experimentally unveiling the carrier‐envelope phase dynamics of a cw‐seeded femtosecond optical parametric amplifier (OPA). Particularly, it is experimentally demonstrated for the first time that unexpectedly low seed power levels suffice to exceed vacuum fluctuations by more than an order of magnitude, resulting in pulse‐to‐pulse phase fluctuations of 82 mrad at rather moderate cw seed levels of 8 mW. Additionally, a formula is provided that allows exact prediction of the experimentally observed noise levels. This study therefore provides new insight into the role of vacuum fluctuations in OPAs, which open up an avenue for coherent dual‐comb systems in the mid‐infrared and beyond.

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