Random lasing in porous scattering medium |
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Authors: | Vasil P Yashchuk O Prygodiuk V Koreniuk E Tikhonov V Bezrodny |
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Institution: | (1) Physics Department, Taras Shevchenko Kyiv National University, Glushkov Ave. 2, Build. 1, Kyiv, 03680, Ukraine;(2) Institute for Physics of Ukraine NAS, Nauky Ave. 46, Kyiv, 03650, Ukraine |
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Abstract: | The spectrum behavior evolution and the threshold of random lasing depending on the way of photon walk randomization in an
active random medium were investigated. The following three ways of photon walk randomization were implemented: multiple light
scattering by corundum and silica particles embedded into a solid polymer solution of dye (astrafloxin), multiple light reflection
at sub-millimeter extensive air pores (mean diameter 200 μm) produced in the medium, and the combined action of both these
effects. The most effective lasing is observed in the case of an active medium with air pores and scattering particles in
the interpore space. Such a combined porous scattering medium acts as a network of dielectric waveguides transmitting effectively
the random light. This spatial structure of the random active medium significantly increases the photon path in the medium,
thereby promoting photon multiplication due to stimulated emission. In this combined medium the random lasing reveals the
narrowest spectrum, the lowest threshold, and the highest density of spectral energy in the spectrum maximum. |
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Keywords: | PACS" target="_blank">PACS 42 25 Dd 42 55 Zz |
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