Interferometric Optics

Nanoparticle-Polymer Laser Media

In the 1990s material scientists working on new solid-state dye laser gain media introduced hybrid polymer-silica dye-doped matrices in an effort to improve the thermal characteristics of polymer-based gain media. These matrices belong in the broader organic-inorganic category. A significant problem associated with these new dye laser matrices was the observed laser beam inhomogeneity (also known as "laser beam break-up"). Later it was determined that this phenomenon was the result of internal interference resulting from the interaction of coherent light and the polymer-silica structure present in the gain matrix (Duarte and Pope (1995)). In other words, the presence of silica was visible via the observed laser beam inhomogeneities.

A solution to this problem was demonstrated by Duarte and James in (2003) by the use of silica nanoparticle distributions in the polymer matrix. Thus, using advances in polymer gain media, and nanoparticle techniques, it was possible to satisfy the interferometric requirements necessary to achieve invisibility of nanoparticle distributions in the visible spectrum. This has been demonstrated experimentally in solid-state organic-inorganic dye-doped gain media and characterized via the detection of laser beam profiles.

The photograph shown here corresponds to Fig. 2 of Duarte and James (2003) and shows a near-Gaussian laser beam following propagation in a dye-doped nanoparticle-polymer composite gain medium. Further, laser oscillation was achieved in this medium which yielded a homogeneous near-Gaussian emission beam. The homogeneity of the laser beam provides elegant evidence that the silica nanoparticles (present in 30% weight by weight in the polymer matrix) are highly transparent and essentially invisible to the laser radiation. The use of nano-particles configured in core-shell structures, to enhance invisibility in laser media, is discussed in Duarte and James (2005). Further details are

  • F. J. Duarte and E. J. A. Pope, Optical inhomogeneities in sol-gel derived ormosils and nanocomposites, in Sol-Gel Science and Technology, Ceramic Transactions, Vol. 55 (The American Ceramic Society, Westerville, 1995) pp.267-273.
  • F. J. Duarte and R. O. James, Tunable solid-state lasers incorporating dye-doped polymer-nanoparticle gain media, Opt. Lett. 28, 2088-2090 (2003).
  • F. J. Duarte and R. O. James, Spatial structure of dye-doped polymer-nanoparticle laser media, Appl. Opt. 43, 4088-4090 (2004).
  • F. J. Duarte and R. O. James, Dye-doped, polymer-nanoparticle gain media for tunable solid-state lasers, Mat. Res. Soc. Symp. Proc. 817, 201-206 (2004).
  • F. J. Duarte and R. O. James, Dye-doped polymer nanoparticle gain medium, US Patent 6888862 (3rd of May, 2005).
  • F. J. Duarte and R. O. James, Tunable lasers based on dye-doped polymer gain media incorporating homogeneous distributions of functional nanoparticles, in Tunable Laser Applications, 2nd Ed., F. J. Duarte (Ed.) (CRC, 2008) Chapter 4.

Background Bibliography
  • M. Kerker, Invisible bodies, J. Opt. Soc. Am. 65, 376 (1975).
  • M. Kerker, Elastic scattering, absorption, and surface-enhanced raman scattering by concentric spheres comprised of a metallic and a dielectric region, Phys. Rev. B 26, 4052-4063 (1982).
  • R. O. James, L. A. Rowley, D. F. Hurley, and J. Border, Core shell nanocomposite optical plastic article, US Patent 7091271(15th of August, 2006).

Interferometric Optics
Optical Metrology for Inkjet Printers and Laser Printers
Optics Journal
Tunable Lasers

Published on the 13th of January, 2007; updated on the 2nd of June, 2015.