0000000001274822
AUTHOR
Heping Zeng
Dithienopyrrolobenzothiadiazole-based organic dyes for efficient dye-sensitized solar cells
Four novel D–π–A metal-free organic dyes DTP1–4 containing a dithienopyrrolobenzothiadiazole (DTPBT) unit were synthesized and applied in dye-sensitized solar cells, where DTPBT was employed as a π-spacer for the first time. The photophysical, electrochemical and photovoltaic properties of the dyes were systematically investigated. The dyes DTP1–4 showed broad absorption spectra and high molar extinction coefficient, resulting in high light harvesting efficiency. In addition, the impacts of donors and the thiophene unit as an additional π-spacer were also studied. The results showed that the dye DTP4 with triphenylamine as the donor exhibited better photovoltaic performance than DTP1–3 with…
Self-Optimising Breather Ultrafast Fibre Laser
We demonstrate the self-optimisation of the breather regime in an ultrafast fibre laser through an evolutionary algorithm. Depending on the specified merit function, single breathers with controllable breathing ratio and period, and breather molecular complexes with a controllable number of constituents can be obtained.
Control of complex nonlinear wave dynamics in dissipative systems by machine learning
Ultrafast mode-locked fibre lasers exploiting nonlinearity in the pulse formation process are well-known to display a rich landscape of "dissipative soliton'' dynamics, which results from the interplay of the nonlinearity with dispersion and dissipation. Reaching a desired operating regime in a fibre laser generally depends on precisely adjusting multiple parameters in a high-dimensional space, in connection with the wide range of accessible pulse dynamics, which is usually performed through a trial-and-error experimental procedure, due to the lack of analytic relationship between the cavity parameters and the pulse features. The practical difficulties associated with such a procedure can b…
Breather Molecular Complexes in a Passively Mode‐Locked Fiber Laser
International audience; Breathing solitons are nonlinear waves in which the energy concentrates in a localized and oscillatory fashion. Similarly to stationary solitons, breathers in dissipative systems can form stable bound states displaying molecule-like dynamics, which are frequently called breather molecules. So far, the experimental observation of optical breather molecules and the real-time detection of their dynamics are limited to diatomic molecules, that is, bound states of only two breathers. In this work, the observation of different types of breather complexes in a mode-locked fiber laser: multibreather molecules, and molecular complexes originating from the binding of two breat…
Effect of the linkage location in double branched organic dyes on the photovoltaic performance of DSSCs
Two novel double branched D–π–A organic dyes (DB dyes) are synthesized to investigate the influence of the linkage location in DB dyes on the performance of dye-sensitized solar cells (DSSCs), where phenothiazine is introduced as a donor, thiophene–benzotriazole unit as the π-bridge and cyanoacrylic acid as the electron-acceptor. The photophysical, electrochemical and photovoltaic properties of the dyes are systematically investigated. The results show that the location of the linkage unit has a small effect on the physical and electrochemical properties of the dyes. However, when the dyes are applied in DSSCs, an obvious decline of short-circuit current (Jsc) and open-circuit voltage (Voc)…
Breather laser dynamics and their intelligent control
Breathers are localized structures showing periodic variations in parameters. They are found in various fields of science, and are currently attracting significant research interest in virtue of their relationship with a rich set of important nonlinear phenomena. They have recently emerged as a universal ultrashort pulse regime in passively mode-locked fibre lasers. Here, we reviewed our recent works in this fast-growing field, including the first observation of breathing dissipative solitons and their complexes in mode-locked fibre lasers[1-3], breather explosions[4], and intelligent control of breathers over breathing periods, breathing ratios, and the number of breathers[5]. Finally, fra…
Accrochage de fréquence dans un laser à fibre à respiration : observation de l’arbre de Farey et de l’escalier du diable
Contrairement au soliton brillant, les solitons à respiration présentent un comportement oscillatoire périodique. L’utilisation des fibres optiques a grandement facilité leur observation: l’interaction sur une grande distance entre la non-linéarité Kerr et la dispersion, en la quasi-absence de dissipation a ainsi permis la caractérisation fine des solitons à respiration d’Akhmediev, de Ma ou bien encore de leur cas limite, le soliton de Peregrine.Grâce au développement des techniques de détection en temps réel, les cavités laser à fibre offrent une autre plateforme extrêmement intéressante. Dans le contexte des lasers ultrarapides à modes bloqués, la génération d’impulsions à respiration co…