Superradiance in Molecular H Aggregates

Meinardi, Francesco; Cerminara, Michele; Sassella, A.; Bonifacio, R.; Tubino, R.

doi:10.1103/physrevlett.91.247401

Cited by 125 publications

(97 citation statements)

References 25 publications

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“…In this case, fluorescence emission is observed in resonance to the lowest energy exciton state. The extended exciton states give rise to many peculiar linear and nonlinear optical properties, such as resonant fluorescence [1,2], super radiant emission [7][8][9], high nonlinear susceptibilities [10], efficient exciton-exciton annihilation [11], and energy migration [12][13][14][15]. The latter was already observed by Scheibe et al [16].…”

Section: Introductionmentioning

confidence: 48%

Photo‐induced reduction of Noble metal ions to metal nanoparticles on tubular J‐aggregates

Kirstein

Berlepsch

Böttcher

2006

International Journal of Photoenergy

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Palladium and silver nanoparticles are formed on the surface of tubular J-aggregates of an amphiphilic tetrachlorobenzimidacarbocyanine dye by reduction of the respective metal cations in aqueous solution. Upon addition of the palladium complex Na 2 PdCl 4 to the aggregate solution, the absorption spectrum shows significant changes which is explained by partial destruction of the aggregates. Cryogenic transmission electron microscopy (cryo-TEM) images show that the tubular J-aggregates are randomly covered by well-separated Pd nanoparticles of approximately 1-3 nm size. Larger particles and higher particle density along the aggregates are obtained when an auxiliary reducing agent is added to the solution. The presence of the metallic particles leads to efficient fluorescence quenching giving clear evidence for super quenching. In similar experiments using AgNO 3 , silver nanoparticles are grown which are larger in size but less dense distributed along the aggregates. At least in the case of the silver particles, the spontaneous formation of metal nanoparticles is assumed to be initiated by a photo-induced electron transfer process (PET).

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Section: Introductionmentioning

confidence: 48%

Photo‐induced reduction of Noble metal ions to metal nanoparticles on tubular J‐aggregates

Kirstein

Berlepsch

Böttcher

2006

International Journal of Photoenergy

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“…8. In an organic quaterthiophene semiconductor whose molecules are arranged in H-aggregate fashion, time-resolved photoluminescence measurements showed that the radiative lifetime had a linear correlation with the inverse of the number of the coherently emitting dipoles, i.e., τ rad ∝ 1/N [102]. More recently, phosphorescence SR was demonstrated in heavy-metal-containing π-conjugated polymers, as a result of the significant spinorbit interaction provided by the large atomic number elements [100].…”

Section: B Molecular Aggregates and Crystalsmentioning

confidence: 99%

“…Cooperative spontaneous emission processes have also been investigated in molecular solids, such as molecular aggregates and crystals, including Jaggregates [96,97], LH-2 photosynthetic antenna complexes [98], π-conjugated polymer thin films [99,100], H-aggregates [101,102], and tetracene thin films and nanoaggregates [103]. In all these studies, accelerated radiative decay was observed and attributed to cooperative emission, although SF, in the form observed in atomic systems (Section II) and molecular centers in crystals (Section III A), has not been reported and some of the reported results and claims remain controversial.…”

Section: B Molecular Aggregates and Crystalsmentioning

confidence: 99%

Dicke superradiance in solids [Invited]

et al. 2016

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Recent advances in optical studies of condensed matter systems have led to the emergence of a variety of phenomena that have conventionally been studied in the realm of quantum optics. These studies have not only deepened our understanding of light-matter interactions but also introduced aspects of many-body correlations inherent in optical processes in condensed matter systems. This article is concerned with the phenomenon of superradiance (SR), a profound quantum optical process originally predicted by Dicke in 1954. The basic concept of SR applies to a general N -body system where constituent oscillating dipoles couple together through interaction with a common light field and accelerate the radiative decay of the whole system. Hence, the term SR ubiquitously appears in order to describe radiative coupling of an arbitrary number of oscillators in many situations in modern science of both classical and quantum description. In the most fascinating manifestation of SR, known as superfluorescence (SF), an incoherently prepared system of N inverted atoms spontaneously develops macroscopic coherence from vacuum fluctuations and produces a delayed pulse of coherent light whose peak intensity ∝ N 2 . Such SF pulses have been observed in atomic and molecular gases, and their intriguing quantum nature has been unambiguously demonstrated. In this review, we focus on the rapidly developing field of research on SR phenomena in solids, where not only photon-mediated coupling (as in atoms) but also strong Coulomb interactions and ultrafast scattering processes exist. We describe SR and SF in molecular centers in solids, molecular aggregates and crystals, quantum dots, and quantum wells. In particular, we will summarize a series of studies we have recently performed on semiconductor quantum wells in the presence of a strong magnetic field. In one type of experiment, electron-hole pairs were incoherently prepared, but a macroscopic polarization spontaneously emerged and cooperatively decayed, emitting an intense SF burst. In another type of experiment, we observed the SR decay of coherent cyclotron resonance of ultrahigh-mobility two-dimensional electron gases, leading to a decay rate that is proportional to the electron density. These results show that cooperative effects in solid-state systems are not merely small corrections that require exotic conditions to be observed; rather, they can dominate the nonequilibrium dynamics and light emission processes of the entire system of interacting electrons.

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“…Such molecules pack in a herringbone arrangement with at least 2 molecules in a unit cell. [20][21][22][23] Here, the lower Davydov component ͑alias J-band͒ is weakly allowed along the crystal b direction, 20,[24][25][26] leading to b-polarized superradiant 0-0 emission 27 which diminishes with increasing disorder. [28][29][30][31] In helical MOPVn aggregates, coherence affects the PL spectrum in a manner similar to the ideal linear H-aggregates described above.…”

Section: Introductionmentioning

confidence: 99%

Using circularly polarized luminescence to probe exciton coherence in disordered helical aggregates

Spano

Meskers

Hennebicq

et al. 2008

The Journal of Chemical Physics

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Circularly polarized emission from helical MOPV4 aggregates is studied theoretically based on a Hamiltonian including excitonic coupling, exciton phonon coupling, and site disorder. The latter is modeled via a Gaussian distribution of site energies. The frequency dependence of the circularly polarized luminescence dissymmetry g lum ͑͒ contains structural information about the low-energy-neutral ͑excitonic͒ polaron from which emission originates. Near the 0-0 emission frequency, g lum ͑͒ provides a measure of the exciton coherence length, while at lower energies, in the vicinity of the sideband frequencies, g lum ͑͒ probes the polaron radius. The present work focuses on how the 0-0 dissymmetry, g lum 0-0 , relates to the emitting exciton's coherence function, from which the coherence length is deduced. In the strong disorder limit where the exciton is localized on a single chromophore, g lum 0-0 is zero. As disorder is reduced and the coherence function expands, ͉g lum 0-0 ͉ increases more rapidly than the sideband dissymmetries, resulting in a pronounced surge in g lum ͑͒ near the 0-0 transition frequency. The resulting spectral shape of g lum ͑͒ is in excellent agreement with recent experiments on MOPV4 aggregates. In the limit of very weak disorder, corresponding to the motional narrowing regime, the coherence function extends over the entire helix. In this region, g lum 0-0 undergoes a surprising sign reversal but only for helices which are between n + 1 2 and n + 1 complete turns ͑n =0,1, ...͒. This unusual sign change is due to the dependence of the rotational line strength on long-range exciton coherences which are also responsible for a heightened sensitivity of g lum ͑͒ to long-range excitonic coupling.

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Superradiance in Molecular H Aggregates

Cited by 125 publications

References 25 publications

Photo‐induced reduction of Noble metal ions to metal nanoparticles on tubular J‐aggregates

Photo‐induced reduction of Noble metal ions to metal nanoparticles on tubular J‐aggregates

Dicke superradiance in solids [Invited]

Using circularly polarized luminescence to probe exciton coherence in disordered helical aggregates

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