arXiv subjects

David A. Czaplewski

Publications and source records attributed to David A. Czaplewski.

21 records · Page 2Linked to original sources

arXiv2015

Silicon-nitride photonic circuits interfaced with monolayer MoS$_2$

We report on the integration of monolayer molybdenum disulphide with silicon nitride microresonators assembled by visco-elastic layer transfer techniques. Evanescent coupling from the resonator mode to the monolayer is confirmed through measurements of cavity transmission. The absorption of the monolayer semiconductor flakes in this geometry is determined to be 850 dB/cm, which is larger than that of graphene and black phosphorus with the same thickness. This technique can be applied to diverse monolayer semiconductors for assembling hybrid optoelectronic devices such as photodetectors and modulators operating over a wide spectral range.

cond-mat.mtrl-sci↗

arXiv2014

Ultracompact Nano-Mechanical Plasmonic Phase Modulators

Dielectrics' refractive index limits photonics miniaturization. By coupling light to metal's free electrons, plasmonic devices achieve deeper localization, which scales with the device geometric size. However, when localization approaches the skin depth, energy shifts from the dielectric into the metal, hindering active modulation. Here we propose a nano-electromechanical phase modulation principle exploiting the extraordinarily strong dependence of the phase velocity of metal-insulator-metal(MIM) gap plasmons on dynamically variable gap size. We demonstrate a 23 μm long non-resonant modulator having 1.5 π rad range with 1.7 dB excess loss at 780 nm. Analysis shows an ultracompact 1 μm$^{2}$ footprint π rad phase modulator can be realized, more than an order of magnitude smaller than any previously shown. Remarkably, this size reduction is achieved without incurring extra loss, since the nanobeam-plasmon coupling strength increases at a similar rate as the loss. Such small, high density electrically controllable components may find applications in optical switch fabrics and reconfigurable flat plasmonic optics.

physics.optics↗

arXiv2013

Experimental demonstration of near-infrared epsilon-near-zero multilayer metamaterial slabs

Near-infrared epsilon-near-zero (ENZ) metamaterial slabs based on silver-germanium (Ag-Ge) multilayers are experimentally demonstrated. Transmission, reflection and absorption spectra are characterized and used to determine the complex refractive indices and the effective permittivities of the ENZ metamaterial slabs, which match the results obtained from both the numerical simulations and the optical nonlocalities analysis. A rapid post-annealing process is used to reduce the collision frequency of silver and therefore decrease the optical absorption loss of multilayer metamaterial slabs. Furthermore, multilayer grating structures are studied to enhance the optical transmission and also tune the location of ENZ wavelength. The demonstrated near-infrared ENZ multilayer metamaterial slabs are important for realizing many exotic applications, such as phase front shaping and engineering of photonic density of states.

physics.optics↗