1. Optics on a Nanoscale Using Polaritonic and Plasmonic Materials (NSF NIRT 0709323) Andrey Chabanov 1, Federico Capasso 2, Vinothan Manoharan 2, Michael Spencer 3, Gennady Shvets 4, Christian Zorman 5 1 University of Texas-San Antonio, 2 Harvard University, 3 Cornell University, 4 University of Texas-Austin, 5 Case Western Reserve University Motivation and Goals: Coupling Optical Energy to Nanoscale Light diffraction prevents confinement of light in regions smaller than half a laser wavelength thus impeding the development of future nanophotonic devices and limiting future nanoimaging applications. Surface polaritons, on the other hand, can have wavelengths that are orders of magnitude shorter than in vacuum. Thus plasmonic/ polaritonic components may enable us to achieve unprecedented focusing of optical energy that can address the needs of nanophotonics, nanomanufacturing, NEMS, nanoscale thermal source development, and nanofluidics. The Key Challenges in coupling optical energy to nanoscale are addressed by the NIRT: (i) Creating nanoscale polariton-based building blocks of metamaterials/ metafluids with controlled optical properties; (ii) Accomplishing strongly subwavelength, nanoscale resolution by designing a mid-infrared polariton- based superlens integrated with a scattering NSOM; (iii) Demonstration of extraordinary optical energy focusing on a nanoscale through the excitation and guiding of surface polaritons. The plasmonic/ polaritonic components aimed by the NIRT are to lead to in vivo imaging of nanoscale biological objects and revolutionize label-free detection of biological and chemical substances. Artificial Plasmonic Molecules-based metafluids Liquid metamaterials, or metafluids, are based on clusters of metallic nanoparticles, or Artificial Plasmonic Molecules (APMs), which exhibit strong electric and magnetic responses. Colloidal solutions of plasmonic nanoclusters can act as an optical medium with very large, small, or even negative effective permittivity and substantial effective magnetic permeability in the visible and near-infrared spectral bands. The properties of the metafluids can be controlled by an external signal. 130-nm SiO 2 core, 25-nm thick gold shell170-nm SiO 2 core, 25-nm thick gold shell 180-nm diameter nanoshell trimer 220-nm diameter nanoshell trimer  Silica cores are synthesized and functionalized with a silane linker  Gold nanoparticles are self- assembled onto the surface and gold shells with controllable shell thickness are created by electroless deposition  Gold nanoshells are assembled into trimers using capillary-force clustering or DNA-mediated adhesion  Single nanoshell absorption spectra of particles are measured in air on a glass substrate Seeing through water: in vivo imaging of small biological objects Subsurface imaging through a SiC-superlens microstructure nanofluidic channel SiC PDMS NSOM tip SiC film PDMS water  Resolution of λ/20 for 2-D objects (holes)  Increased range of frequencies for imaging  amplitude or phase  Higher resolution with phase imaging  less sensitive to topography  Bonding of SiC membranes to PDMS holder demonstrated  Fluid delivery system (microfluidic channels connect to the nanofluidic sub-surface channel) developed and tested  Presently working on the inscription of small objects (holes, metal discs, etc.) at the bottom of the nanofluidic channel λ=9.27 µm λ=10.85 µm λ=10.62 µm λ=11.03 µm Amplitude image Phase image SEM image 500 nm middle holes continuous silver wires control  eff 80 nm 20 nm 320 nm 80 nm 50 nm 250 nm “cut” silver wires control  eff impedance matching  re =  re = -1 Perfect impedance matched negative index material absorber This structure is subwavelength (period ~ λ/5 ) and operates in ε = μ = -1 regime  Peak absorption varies between 100% and 75% for the 90-deg full-angle spread  Absorption peak is spectrally narrow (10%) and widely tunable (1300nm < λ < 1600nm)  Using high melting temperature metals (e.g. tungsten) shifts the wavelength to λ = 2.4 μm and enables thermovoltaic applications  Using SiC  shifts resonances to λ = 11 μm  night-vision applications