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Spectral narrowing and lasing threshold in self-assembled active photonic crystal

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Title Spectral narrowing and lasing threshold in self-assembled active photonic crystal
 
Creator KEDIA, S
VIJAYA, R
RAY, AK
SINHA, S
 
Subject INHIBITED SPONTANEOUS EMISSION
LASER-LIKE EMISSION
RHODAMINE 6G
OPAL
Photonic crystal
Spontaneous emission
Lasing
Self-assembly
 
Description Laser-induced emission from rhodamine-B dye embedded in pseudo band gap opaline photonic crystals is discussed. The photonic crystals are fabricated using rhodamine-B doped polystyrene colloids and show 65% reflectance at the stop band centered at 604 nm. The reflectance of the crystal is increased to 74% by coating with a thin layer of gold. Both spontaneous and stimulated emissions of the dye are observed in the photonic stop band environment by exciting the crystal with the second harmonic (532 nm) of a Q-switched Nd:YAG laser. The thin layer of gold functioned as a high reflecting end mirror to the dye-doped cavity when the crystal is pumped from the substrate side. Angle-dependent suppression at the stop band wavelength is observed in the spontaneous emission of the dye. Spectrally narrow stimulated emission and lasing is achieved in the gold coated dyed PhC at a threshold pump power of 60 mW in a selective direction of 22 degrees from the direction of excitation. By studying emission from several photonic crystals with different number of layers, it is concluded that a sharp threshold for lasing is not observed in uncoated photonic crystals when they contained fewer than 30 ordered layers and lesser than 70% reflectance. (c) 2011 Elsevier B.V. All rights reserved.
 
Publisher ELSEVIER SCIENCE BV
 
Date 2012-06-26T07:46:41Z
2012-06-26T07:46:41Z
2011
 
Type Article
 
Identifier OPTICS COMMUNICATIONS,284(7)2056-2060
0030-4018
http://dx.doi.org/10.1016/j.optcom.2010.12.056
http://dspace.library.iitb.ac.in/jspui/handle/100/14172
 
Language English