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Arup Neogi Department of Physics and Materials Engineering University of North Texas

Explore nanoscale optoelectronic and biophotonic materials for efficient light emission, with research areas in Ultrafast and Nanoscale Photonics. Funding from NSF, US DOE, and JSPS. Investigating surface plasmons polariton coupling and energy transfer in quantum dots. Temperature-induced changes in hydrogels, scattering properties, and electric field effects in PNIPA gels. Published research by Arup Neogi and Zhibing Hu.

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Arup Neogi Department of Physics and Materials Engineering University of North Texas

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  1. Engineering Spontaneous Emission in Hybrid Nanoscale Materials for Optoelectronics and Bio-photonics Arup Neogi Department of Physics and Materials Engineering University of North Texas Email: arup@unt.edu

  2. Research Areas http://www.phys.unt.edu/research/photonic/website/ • Nanoscale Optoelectronic materials for efficient light emission • Biophotonic materials; for hybrid molecular electronics and photonics Ultrafast and Nanoscale Photonics GroupArup Neogi, Department of Physics • Funding: • National Science Foundation • US Department of Energy • Japan Soc. for Promotion of Sciences

  3. Surface plasmons polariton coupling with directional emission • Using subwavelength corrugated surface grating: • Momentum can be transferred to couple the light and plasmon modes • Directional Emission can be improved by using corrugated surfaces

  4. Change in radiative recombination lifetime in Qdots due to resonant exciton-surface plasmon coupling Radiative recombination rate in strained quantum dots emission - observed above the SP emission energy

  5. Energy Transfer in Quantum Dots entrapped in Hydrogel Microspheres Arup Neogi, Zhibing Hu Department of Physics University of North Texas

  6. 1 cm 1 cm 21 oC 35 oC The NIPAM sample in water: Effect of temperature61 Temperature induced changes in hydrogel The phase transition temperature (Tc) of PNIPAM is 34 °C. below Tc, the hydrogel is hydrophilic and swells in water, while above Tc it is hydrophobic and collapses into a small volume.

  7. Change in scattering properties with particle size Variation of Particle size with chemistry Change in scattering properties with turbidity

  8. UV Sunlight The PL image of PNIPAM/CdTe microgel under UV lamp. The image of PNIPAM/CdTe microgel under sunlight Photoluminescence Spectrum of QDs embedded in GEL

  9. Electric Field Induced effects in PNIPA Gels At room temperature No electric field 3.5V/cm electric field *Wu, J. et. al. Phys. Rev. Lett., 90, 48304 (2003) +Hu, Z. et. al. Advan. Mater.13, 1708 (2001)

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