We describe the underlying theories and experimental demonstrations of passive temperature stabilization of silicon photonic devices clad in nematic liquid crystal mixtures, and active optical tuning of silicon photonic resonant structures combined with dye-doped nematic and blue phase liquid crystals. We show how modifications to the resonator device geometry allow for not only enhanced tuning of the resonator response, but also aid in achieving complete athermal operations of silicon photonic circuits. [Ref.: I.C. Khoo, "DC-field-assisted grating formation and nonlinear diffractions in methyl-red dye-doped blue phase liquid crystals," Opt. Lett. 40, 60-63 (2015); J. Ptasinski, I.C. Khoo, and Y. Fainman, "Enhanced optical tuning of modified-geometry resonators clad in blue phase liquid crystals," Opt. Lett. 39, 5435-5438 (2014); J. Ptasinski, I.C. Khoo, and Y. Fainman, "Passive Temperature Stabilization of Silicon Photonic Devices Using Liquid Crystals," Materials 7(3), 2229-2241 (2014)].
Silicon photonics allows for high density component integration on a single chip and it brings promise for low-loss, high-bandwidth data processing in modern computing systems. Owing to silicon’s high positive thermo-optic coefficient, temperature fluctuations tend to degrade the device performance. This work explores passive thermal stabilization of silicon photonic devices using nematic liquid crystal (NLC) claddings, as they possess large negative thermo-optic coefficients in addition to low absorption at the telecommunication wavelengths.
Silicon photonics is a rapidly evolving field allowing for optical devices to be made cost effectively using standard semiconductor fabrication techniques and integrated with microelectronic chips. Active tuning of silicon photonic devices has been demonstrated using thermal, electrical and optical means in the form of injection of free carriers through two-photon absorption. This work explores active electrical and optical tuning of silicon photonic devices using silicon strip waveguides combined with nematic liquid crystal (NLC) claddings. Simulation and experimental studies are presented.
Nano-Plasmonics possesses unique physical properties that enable localization of optical fields beyond the diffraction
limit. These highly confined/nanoscale optical modes will enhance light/matter interactions in systems with free
electrons in micro/nanoscale geometric structures. Metal-dielectric fluid interfaces can support surface plasmon
polaritons (SPPs), which are electromagnetic modes interacting with free electron oscillations. Research work is
described on using optofluidic plasmonic chips for implementation of an optofluidic plasmonic sensor, demonstrating in
situ, real time, label-free detection of protein-protein interaction. SPP lineshape is modified from Fano to Lorentz for
increase of the figure of merit to increase the limit of detection. Novel metal-dielectric nanoresonator composites is
presented to increase the surface sensitivity by exciting localized surface plasmon resonance (LSPR) in combination with
SPP readout, enabling higher surface field localization. In order to solve the long time challenging issue of overlapping
molecule of interest onto LSPR to realize the maximal interaction cross-section, micro-nanofluidics integrated nanochip
was developed. We employed electrokinetic forces to control and manipulate the nanoparticles onto the predefined
Photonic crystals (PCs) have been one of the new, exhilarating topics in the last decade. The intent of this
paper is to provide an understanding of two dimensional PC waveguides and the guiding mechanism
associated with the structures. The basic understanding of two dimensional waveguides can be applied to
more complex structures such as those found in three dimensional PCs. Results presented consist of
different two dimensional waveguide cases, for both the line defect and the coupled cavity variety. It has
been shown that PCs do not rely on index guiding, as conventional optical waveguides do, but that they do
rely on distributed Bragg reflection. It has also been shown that in the case of defects, such as a
waveguide, the size of the photonic bandgap is not the main determinant of wave confinement in that
waveguide. The group index is a good measure of the degree of reflection one expects to see along the
propagation direction of a waveguide.