skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Angular dependent light emission from planar waveguides

Abstract

We have investigated the angular dependence of amplified spontaneous emission (ASE) and laser emission from an asymmetric and free-standing polymer thin films doped with rhodamine 6G, which is transversely pumped by a pulsed Nd:YAG laser. A semi-leaky waveguide or quasi-waveguide structure has been developed by spin coating technique. In these waveguides, the light was confined by the film/air-film/glass substrate interfaces. At the film/substrate interface, a portion of light will reflect back into the film (guided mode) and the remaining refracted to the substrate resulting in cutoff modes. A blue-shift in ASE has been observed when the pump power was increased from 8 to 20 mW allowing a limited range of tuning of emission wavelength. To study the directionality of the ASE from the waveguide, we have measured the output intensity and FWHM of emission spectra as a function of viewing angle (θ) from the plane parallel to film. From the detailed examination of the output emission spectra, as +θ increases from 0° there has been an initial decrease in output intensity, but at a particular angle ≈10° an increase in output intensity was observed. This additional peak in output intensity as +θ is a clear indication of coexistence of themore » cutoff mode. We also present a compact solid-state laser based on leaky mode propagation from the dye-doped polymer free-standing film (∼50 μm thickness) waveguide. The partial reflections from the broad lateral surfaces of the free-standing films provided the optical feedback for the laser emission with high directionality. For a pump power of 22 mW, an intense line with FWHM <0.2 nm was observed at 578 nm.« less

Authors:
 [1];  [2];  [3]; ; ; ;  [1]
  1. International School of Photonics, Cochin University of Science and Technology, Cochin 682022 (India)
  2. (United Kingdom)
  3. CRE"+E, IDEAS Research Institute, Robert Gordon University, Aberdeen AB10 7GJ (United Kingdom)
Publication Date:
OSTI Identifier:
22399231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AIR; ASYMMETRY; DOPED MATERIALS; EMISSION SPECTRA; GLASS; INTERFACES; NEODYMIUM LASERS; POLYMERS; REFLECTION; RHODAMINES; SPIN-ON COATING; SUBSTRATES; SURFACES; THICKNESS; THIN FILMS; VISIBLE RADIATION; WAVEGUIDES

Citation Formats

Peter, Jaison, E-mail: jaison.peter@gmail.com, CRE"+E, IDEAS Research Institute, Robert Gordon University, Aberdeen AB10 7GJ, Prabhu, Radhakrishna, Radhakrishnan, P., Vallabhan, C. P. G., Nampoori, V. P. N., and Kailasnath, M.. Angular dependent light emission from planar waveguides. United States: N. p., 2015. Web. doi:10.1063/1.4905011.
Peter, Jaison, E-mail: jaison.peter@gmail.com, CRE"+E, IDEAS Research Institute, Robert Gordon University, Aberdeen AB10 7GJ, Prabhu, Radhakrishna, Radhakrishnan, P., Vallabhan, C. P. G., Nampoori, V. P. N., & Kailasnath, M.. Angular dependent light emission from planar waveguides. United States. doi:10.1063/1.4905011.
Peter, Jaison, E-mail: jaison.peter@gmail.com, CRE"+E, IDEAS Research Institute, Robert Gordon University, Aberdeen AB10 7GJ, Prabhu, Radhakrishna, Radhakrishnan, P., Vallabhan, C. P. G., Nampoori, V. P. N., and Kailasnath, M.. Wed . "Angular dependent light emission from planar waveguides". United States. doi:10.1063/1.4905011.
@article{osti_22399231,
title = {Angular dependent light emission from planar waveguides},
author = {Peter, Jaison, E-mail: jaison.peter@gmail.com and CRE"+E, IDEAS Research Institute, Robert Gordon University, Aberdeen AB10 7GJ and Prabhu, Radhakrishna and Radhakrishnan, P. and Vallabhan, C. P. G. and Nampoori, V. P. N. and Kailasnath, M.},
abstractNote = {We have investigated the angular dependence of amplified spontaneous emission (ASE) and laser emission from an asymmetric and free-standing polymer thin films doped with rhodamine 6G, which is transversely pumped by a pulsed Nd:YAG laser. A semi-leaky waveguide or quasi-waveguide structure has been developed by spin coating technique. In these waveguides, the light was confined by the film/air-film/glass substrate interfaces. At the film/substrate interface, a portion of light will reflect back into the film (guided mode) and the remaining refracted to the substrate resulting in cutoff modes. A blue-shift in ASE has been observed when the pump power was increased from 8 to 20 mW allowing a limited range of tuning of emission wavelength. To study the directionality of the ASE from the waveguide, we have measured the output intensity and FWHM of emission spectra as a function of viewing angle (θ) from the plane parallel to film. From the detailed examination of the output emission spectra, as +θ increases from 0° there has been an initial decrease in output intensity, but at a particular angle ≈10° an increase in output intensity was observed. This additional peak in output intensity as +θ is a clear indication of coexistence of the cutoff mode. We also present a compact solid-state laser based on leaky mode propagation from the dye-doped polymer free-standing film (∼50 μm thickness) waveguide. The partial reflections from the broad lateral surfaces of the free-standing films provided the optical feedback for the laser emission with high directionality. For a pump power of 22 mW, an intense line with FWHM <0.2 nm was observed at 578 nm.},
doi = {10.1063/1.4905011},
journal = {Journal of Applied Physics},
number = 1,
volume = 117,
place = {United States},
year = {Wed Jan 07 00:00:00 EST 2015},
month = {Wed Jan 07 00:00:00 EST 2015}
}