Random lasing in porous scattering medium

• Published in: Applied physics. B, Lasers and optics Lasers and optics, 2008-09, Vol.92 (4), p.593-597, Article 593
• Main Authors: Yashchuk, Vasil P., Prygodiuk, O., Koreniuk, V., Tikhonov, E., Bezrodny, V.
• Format: Article
• Language: English
• Subjects: Applied physics; Corundum; Density; Dielectric waveguides; Diffraction and scattering; Engineering; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Lasers; Lasing; Light reflection; Multiplication; Optical Devices; Optics; Photonics; Photons; Physical Chemistry; Physics; Physics and Astronomy; Porosity; Porous media; Quantum Optics; Random lasers; Randomization; Scattering; Stimulated emission; Thresholds; Wave optics; Wave propagation in random media
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-008-3118-z

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.