Optical devices

1D Bragg mirrors

We are interested in the fabrication of high refractive index composite and periodic materials. For example, by using highly loaded ZrO2/elastomer resins, we could achieve sufficient refractive index contrast to prepare a 1D photonic crystal (Bragg mirror), which was used for colorimetric strain sensing. Additionally, we have also demonstrated the fabrication of 1D photonic crystals through the self-assembly of brush block copolymers highly-loaded with ZrO2.

Figure. 1D photonic crystals through top-down and bottom up approaches.

           

In another project, we prepared photonic thermosetting polymeric resins using brush block copolymer (BBCP) templates and phenolic resins. Control of the interplay between order and disorder in the photonic structure offers a powerful tool box for designing the optical appearance of the polymer resins in terms of reflected wavelength and scattering properties. The obtained materials exhibit excellent mechanical properties with hardness up to 172 MPa and Young’s modulus over 2.9 GPa, enabling practical uses as photonic coatings on a variety of surfaces.

Figure. Colorful cross-linked PF resins via the self-assembly of composites containing PtBA-b-PEO BBCP and PF resol.

 

Direct Imprinting of large-area, hybrid, 3D photonic crystal structures and optical gratings

We developed a readily scalable print, lift, and stack approach for producing large-area, 3D photonic crystal (PC) structures and optical gratings. UV-assisted nanoimprint lithography was used to pattern grating structures composed of highly filled nanoparticle (NP) polymer composite resists with tunable refractive indices (RI). The gratings were robust and upon release from a support substrate were oriented and stacked to yield 3D PCs. The RI of the composite resists was tuned between 1.58 and 1.92 at 800 nm while maintaining excellent optical transparency. Additionally, we show photonic bandgap behavior of layer-by-layer patterned 3D TiO2 woodpile photonic crystals using both hybrid and inorganic inks.

Figure. SEM images of inorganic tetralayer woodpile 3D photonic crystal structures.

 

We fabricate plasmonic grating structures of TiN by nanoimprint patterning of TiO2, followed by nitridation.

Figure. EDS of nitrided TiO2 gratings for use in exciting surface plasmon polaritons.

 

Related Publications:

  • Kim, P.; Li, C.; Riman, R.E.; Watkins, J.J., 2018. Refractive Index Tuning of Hybrid Materials for Highly Transmissive Luminescent Lanthanide Particle–Polymer Composites. ACS Applied Materials & Interfaces 10(10), 9038-9047. 
  • Li, S.; Kazemi-Moridani, A.; Zhou, Y.; Howell, I.R.; Kothari, R.; Lee, J.H; Watkins, J.J., 2018. Wavelength-Selective Three-Dimensional Thermal Emitters via Imprint Lithography and Conformal Metallization. ACS Applied Materials & Interfaces,10(9), 8173-8179.
  • Howell, I.R.; Giroire, B.; Garcia, A.; Li, S.;, Aymonier, C.; Watkins, J.J., 2018. Fabrication of plasmonic TiN nanostructures by nitridation of nanoimprinted TiO 2 nanoparticles. Journal of Materials Chemistry C 6(6),1399-1406.
  • Song, D.-P.; Shahin, S.; Xie, W.; Mehravar, S.; Liu, X.; Li, C.; Norwood, R. A.; Lee, J.-H.; Watkins, J. J., 2016. Directed Assembly of Quantum Dots Using Brush Block Copolymers for Well-Ordered Nonlinear Optical Nanocomposites. Macromolecules, 49, 5068-5075. 
  • Song, D.P., Li, C., Li, W. and Watkins, J.J., 2016. Block copolymer nanocomposites with high refractive index contrast for one-step photonics. ACS nano, 10(1), pp.1216-1223.
  • Howell, I.R., Li, C., Colella, N.S., Ito, K. and Watkins, J.J., 2015. Strain-tunable one dimensional photonic crystals based on zirconium dioxide/slide-ring elastomer nanocomposites for mechanochromic sensing. ACS Applied Materials & Interfaces, 7(6), pp.3641-3646.
  • Beaulieu, M.R.; Hendricks, N.R.; Watkins, J.J., 2014. Large-Area Printing of Optical Gratings and 3D Photonic Crystals Using Solution-Processable Nanoparticle/Polymer Composites. ACS Photonics 1(9) 799-805.