Theory of laser action in scattering gain media

Light‐emitting organic materials continue to assume increasing significance in the field of semiconductor laser research, and the Figure depicts several structures that have been demonstrated using organic semiconductors. This review provides a description of the fundamental aspects of lasers and a historical overview of their development, followed by a discussion of the recent progress in optically pumped lasers, and their implications for laser technology.

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“…The stimulated emission in this case was enhanced through the use of TiO 2 nanoparticles. [23] Later that year, Tessler et al…”

Section: Historical Overview Of Lasing In Organic Materialsmentioning

confidence: 99%

Lasers Based on Semiconducting Organic Materials

Tessler¹

1999

Adv. Mater.

406

261

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“…Ab-initio computational studies were limited to 1D and 2D geometries [27,28], not accounting for the critical character of three-dimensional (3D) localization [29]. Monte-Carlo simulations neglect interference effects [30,31,32]. Here we report on an original theoretical formulation; we quantitatively compare its predictions with experiments and with the first ever reported 3D+1 ab-initio MaxwellBloch simulations.…”

mentioning

confidence: 99%

Condensation in Disordered Lasers: Theory,3D+1Simulations, and Experiments

et al. 2008

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The complex processes underlying the generation of a coherent-like emission from the multiplescattering of photons and wave-localization in the presence of structural disorder are still mostly un-explored. Here we show that a single nonlinear Schroedinger equation, playing the role of the Schawlow-Townes law for standard lasers, quantitatively reproduces experimental results and threedimensional time-domain parallel simulations of a colloidal laser system. PACS numbers:Random lasers (RL) are a rapidly growing field of research, with implications in soft-matter physics, light localization and photonic devices [1,2]. Since the pioneering investigations [3,4], different groups reported on experimental observations, from paint pigments to human tissue [5,6,7,8,9]. In all of these cases a coherent-like narrow spectral line emerges from the fluorescence as the pump energy is increased and, in some instances, several spectral peaks have been reported [9,10]. In standard single-mode lasers, without structural disorder, the emission linewidth is linked to the electromagnetic energy stored in the cavity by the so-called Schawlow-Townes (ST) law [11,12]. An equivalent law for RL is missing. Nevertheless various issues (like the statistical properties and the link with spin-glass theory [9,13,14,15,16,17]), were theoretically analysed, while the leading model (quantitatively compared with experiments) is that based on the light-diffusion approximation [18,19,20,21], which however overlooks the ondulatory character of the involved photons. Within a different perspective, RL is due to several localized electromagnetic (EM) states put into oscillations in a disordered environment (as, e.g., in [9, 17, 22, 23]). In this framework, it is expected that the number of involved modes increases with the pump energy and, correspondingly, the spectrum widens. However, exactly the opposite happens and this is also accompanied by the shortening of the emitted pulse [24,25,26]. In addition, the fact that strong (or Anderson) localization of light sustains the RL action is still debated. Ab-initio computational studies were limited to 1D and 2D geometries [27,28], not accounting for the critical character of three-dimensional (3D) localization [29]. Monte-Carlo simulations neglect interference effects [30,31,32]. Here we report on an original theoretical formulation; we quantitatively compare its predictions with experiments and with the first ever reported 3D+1 ab-initio MaxwellBloch simulations. We show that the RL linewidth is ruled by a nonlinear differential-equation, which is the equivalent of the ST-law, and is formally identical to the nonlinear Schroedinger, or Gross-Pitaevskii (GP), equation governing ultra-cold atoms [33]. There is hence a strict connection between photons in RL and ultra-cold bosons; the spectral narrowing observed in RL is thus ascribed to a condensation process [34] of the involved electromagnetic resonances. Simulations -We consider a vectorial formulation of the Maxwell-Bloch (MB) equations [35,36]. 21 nonl...

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“…These lasers can be tuned to emit different wavelengths by changing the concentration of the dye. A recent area of interest in the dye laser field is the introduction of a scattering media within the dye [108][109][110][111][112][113][114][115][116][117][118][119] . Several authors have found that scattering particles dispersed within a polymer gain media will increase intensity while decreasing the threshold and linewidth of the laser-action emission.…”

Section: Laser Dyes With Scatterersmentioning

confidence: 99%

The Development of Layered Photonic Band Gap Structures Using a Micro-Transfer Molding Technique

Jerome

2001

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Theory of laser action in scattering gain media

Cited by 102 publications

References 14 publications

Lasers Based on Semiconducting Organic Materials

Lasers Based on Semiconducting Organic Materials

Condensation in Disordered Lasers: Theory,3D+1Simulations, and Experiments

The Development of Layered Photonic Band Gap Structures Using a Micro-Transfer Molding Technique

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