Resonance-driven random lasing

Sapienza, Riccardo; García, Pere; Gottardo, S.; Blanco, Alberto; Wiersma, Diederik S.; López, Cefe

doi:10.1038/nphoton.2008.102

Cited by 274 publications

(188 citation statements)

References 23 publications

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“…Ideally however, such photonic devices are prepared through self-assembly alone, without further expenditure of energy or the necessity of costly postprocessing steps. Monodisperse colloidal particles of pure conjugated polymer would be excellent building blocks for these ultimate photonic devices 11,12 . Although semiconducting polymer particles of polypyrrole 13 , polyaniline 14 and polythiophene 15 have been synthesized via oxidation in a dispersion polymerization, colloidal particles of light-emitting conjugated polymers have only been prepared by postpolymerization miniemulsification 16 , reprecipitation 17 or emulsion polymerization using metal-catalysed cross-coupling reactions 18,19 .…”

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confidence: 99%

Monodisperse conjugated polymer particles by Suzuki–Miyaura dispersion polymerization

2012

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The self-assembly of colloidal building blocks into complex and hierarchical structures offers a versatile and powerful toolbox for the creation of new photonic and optoelectronic materials. However, well-defined and monodisperse colloids of semiconducting polymers, which would form excellent building blocks for such self-assembled materials, are not readily available. Here we report the first demonstration of a suzuki-miyaura dispersion polymerization; this method produces highly monodisperse submicrometer particles of a variety of semiconducting polymers. moreover, we show that these monodisperse particles readily self-assemble into photonic crystals that exhibit a pronounced photonic stopgap.

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confidence: 99%

Monodisperse conjugated polymer particles by Suzuki–Miyaura dispersion polymerization

2012

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“…Prospective of random lasing is however strongly hindered by the absence of emission control: random lasers are highly multimode with unpredictable lasing frequencies and polydirectional output. Manipulation of the underlying random structure [14][15][16][17][18][19][20][21][22][23] and recent work constraining the range of lasing frequencies [24,25] have resulted in significant progress toward possible control. However, the ability to choose a specific frequency in generic random lasing systems has not yet been achieved.…”

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confidence: 99%

Taming Random Lasers through Active Spatial Control of the Pump

et al. 2012

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Active control of the pump spatial profile is proposed to exercise control over random laser emission. We demonstrate numerically the selection of any desired lasing mode from the emission spectrum. An iterative optimization method is employed, first in the regime of strong scattering where modes are spatially localized and can be easily selected using local pumping. Remarkably, this method works efficiently even in the weakly scattering regime, where strong spatial overlap of the modes precludes spatial selectivity. A complex optimized pump profile is found, which selects the desired lasing mode at the expense of others, thus demonstrating the potential of pump shaping for robust and controllable singlemode operation of a random laser.PACS numbers: 42.55. Zz,42.25.Dd Multiple scattering of light in random media can be actively manipulated through spatial shaping of the incident wavefront [1]. This technique has allowed advances in focusing [2][3][4], and imaging [5,6], paving the road to actual control of light transport in strongly scattering media [7][8][9]. Introducing gain in disordered media allows amplification of multiply scattered light, leading to the observation of random lasing [10]. The broad range of systems where it has been studied [11] and the fundamental questions it has raised [12,13] has captivated the community for this last decade. Prospective of random lasing is however strongly hindered by the absence of emission control: random lasers are highly multimode with unpredictable lasing frequencies and polydirectional output. Manipulation of the underlying random structure [14][15][16][17][18][19][20][21][22][23] and recent work constraining the range of lasing frequencies [24,25] have resulted in significant progress toward possible control. However, the ability to choose a specific frequency in generic random lasing systems has not yet been achieved. The spatial profile of the pump is an interesting degree of freedom readily available in random laser (e.g., [26,27]). In a regime of very strong scattering where the modes of the random system are spatially localized [28], local pumping allows selection of spatially non-overlapping modes [29,30]. In weaker scattering media however (e.g., [31][32][33]), several hurdles appear toward achieving fine control. Selecting modes is complicated by a narrow distribution of lasing thresholds [34,35] and spatial mode overlap. Increased pumping required in these lossy systems begins to alter the random laser itself. Moreover, modifying the shape of the pump introduces changes to both the spatial and spectral properties of lasing modes [33,[36][37][38]. Such difficulties are typically absent in more conventional lasers, which have employed pump shaping, both electrically [39][40][41][42] and optically [43], to select favorable lasing modes. The question is, can shaping of the incident pump field achieve taming of random lasers?In this letter, we exercise control over the distribution of lasing thresholds via the pump geometry to choose the random laser em...

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“…1 Gain narrowing occurs around the gain maximum (k % 590 nm), and it is believed that l is independent of wavelength for the sample, unlike in recent studies on Mie resonance-driven random laser emission. 21 Although laser emission is observed for the static scattering state, the intensity is evidently enhanced two-fold when the electric field is applied [ Fig. 5(c)].…”

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Lowering the excitation threshold of a random laser using the dynamic scattering states of an organosiloxane smectic A liquid crystal

Morris

Gardiner

Qasim

et al. 2012

Journal of Applied Physics

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Smectic A liquid crystals, based upon molecular structures that consist of combined siloxane and mesogenic moieties, exhibit strong multiple scattering of light with and without the presence of an electric field. This paper demonstrates that when one adds a laser dye to these compounds it is possible to observe random laser emission under optical excitation, and that the output can be varied depending upon the scattering state that is induced by the electric field. Results are presented to show that the excitation threshold of a dynamic scattering state, consisting of chaotic motion due to electro-hydrodynamic instabilities, exhibits lower lasing excitation thresholds than the scattering states that exist in the absence of an applied electric field. However, the lowest threshold is observed for a dynamic scattering state that does not have the largest scattering strength but which occurs when there is optimization of the combined light absorption and scattering properties.

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Resonance-driven random lasing

Cited by 274 publications

References 23 publications

Monodisperse conjugated polymer particles by Suzuki–Miyaura dispersion polymerization

Monodisperse conjugated polymer particles by Suzuki–Miyaura dispersion polymerization

Taming Random Lasers through Active Spatial Control of the Pump

Lowering the excitation threshold of a random laser using the dynamic scattering states of an organosiloxane smectic A liquid crystal

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