Photonic network laser.

We demonstrated lasing in two-dimensional trivalent network structures with short-range order. Despite the lack of translational and rotational symmetries, such structures possess a large isotropic photonic bandgap. Different from those of a photonic crystal, the band-edge modes are spatially localized and have high quality factor.

Control of lasing in biomimetic structures with short-range order.

We demonstrate lasing in photonic amorphous structures that mimic the isotropic nanostructures which produce noniridescent color in nature. Our experimental and numerical studies reveal that lasing becomes most efficient at certain frequencies, due to enhanced optical confinement by short-range order. The optimal lasing frequency can be tuned by adjusting the structure factor. This work shows that lasing in nanostructures may be effectively improved and manipulated by short-range order.

Tunable superconducting nanoinductors.

We characterize inductors fabricated from ultra-thin, approximately 100 nm wide strips of niobium (Nb) and niobium nitride (NbN). These nanowires have a large kinetic inductance in the superconducting state. The kinetic inductance scales linearly with the nanowire length, with a typical value of 1 nH µm(-1) for NbN and 44 pH µm(-1) for Nb at a temperature of 2.5 K. We measure the temperature and current dependence of the kinetic inductance and compare our results to theoretical predictions. We also simulate the self-resonant frequencies of these nanowires in a compact meander geometry. These nanowire inductive elements have applications in a variety of microwave frequency superconducting circuits.

Ionic field effect transistors with sub-10 nm multiple nanopores.

We report a new method to fabricate electrode-embedded multiple nanopore structures with sub-10 nm diameter, which is designed for electrofluidic applications such as ionic field effect transistors. Our method involves patterning pore structures on membranes using e-beam lithography and shrinking the pore diameter by a self-limiting atomic layer deposition process. We demonstrate that 70-80 nm diameter pores can be shrunk down to sub-10 nm diameter and that the ionic transport of KCl electrolyte can be efficiently manipulated by the embedded electrode within the membrane.

Measurement of carrier mobility in silicon nanowires.

We report the first direct capacitance measurements of silicon nanowires (SiNWs) and the consequent determination of field carrier mobilities in undoped-channel SiNW field-effect transistors (FETs) at room temperature. We employ a two-FET method for accurate extraction of the intrinsic channel resistance and intrinsic channel capacitance of the SiNWs. The devices used in this study were fabricated using a top-down method to create SiNW FETs with up to 1000 wires in parallel for increasing the raw capacitance while maintaining excellent control on device dimensions and series resistance. We found that, compared with the universal mobility curves for bulk silicon, the electron and hole mobilities in nanowires are comparable to those of the surface orientation that offers a lower mobility.

Porous tantalum implant in early osteonecrosis of the hip: preliminary report on operative, survival, and outcomes results.

Porous tantalum implants are used in early osteonecrosis of the hip. Device evaluation included surgical time, blood loss, hospitalization, patient-controlled analgesia use, transfusions, implant survival, and outcomes. Mean blood loss was 70 mL. Mean operative time was 36 minutes. Average hospitalization was less than 1 day. No patient required patient-controlled analgesia use or transfusions. Results were compared to a historical vascularized fibular graft population. All parameters were less than the fibular graft groups (P < .00001). All surviving implants (86%) resulted in good to excellent outcomes. Kaplan-Meier analysis at 39 months was 86% and 67% for the implant and fibular graft, respectively (P = .21). Early outcomes demonstrate that porous tantalum implants are a safe option for femoral head salvage. Continued follow-up is necessary to determine the long-term success.

Ultra-compact, low RF power, 10 Gb/s silicon Mach-Zehnder modulator.

Silicon p(+)-i-n(+) diode Mach-Zehnder electrooptic modulators having an ultra-compact length of 100 to 200 mum are presented. These devices exhibit high modulation efficiency, with a V(pi)L figure of merit of 0.36 V-mm. Optical modulation at data rates up to 10 Gb/s is demonstrated with low RF power consumption of only 5 pJ/bit.

Optical modulation using anti-crossing between paired amplitude and phase resonators.

An optical modulator design based upon anti-crossing between coupled silicon microrings with independent amplitude and phase functionality is presented. The device exhibits over 25x improvement in sensitivity to an input drive signal when compared with previously studied microring modulators based on control of waveguide-resonator coupling. The new design also demonstrates an ON-OFF contrast of 14 dB, and has an ultra-compact footprint of 0.003 mm(2). The observed sensitivity enhancement suggests that this modulator may be driven directly by digital CMOS electrical signals with less than 1 V amplitude.

Ultra-high-density phase-change storage and memory.

Phase-change storage is widely used in optical information technologies (DVD, CD-ROM and so on), and recently it has also been considered for non-volatile memory applications. This work reports advances in thermal data recording of phase-change materials. Specifically, we show erasable thermal phase-change recording at a storage density of 3.3 Tb inch(-2), which is three orders of magnitude denser than that currently achievable with commercial optical storage technologies. We demonstrate the concept of a thin-film nanoheater to realize ultra-small heat spots with dimensions of less than 50 nm. Finally, we show in a proof-of-concept demonstration that an individual thin-film heater can write, erase and read the phase of these storage materials at competitive speeds. This work provides important stepping stones for a very-high-density storage or memory technology based on phase-change materials.