Highly efficient nanofocusing for integrated on-chip nanophotonics

A linearly tapered 3D metal–insulator–metal nanoplasmonic photon compressor reduces resistive and scattering losses, showing promise for future nanoscale photonic and plasmonic applications

On-chip low-profile nano-horn metal-clad optical cavity with much improved performance

We propose an on-chip nano-horm-shaped metal-clad cavity. The proposed device is 0.8 µm in height-half the size of the previously reported devices— and achieves the quality factor of 1000 and effective volume of 0.31(λ/n)^3

Optical properties of microlenses fabricated using hydrophobic effects and polymer-jet-printing technology

We describe high-precision microlenses with excellent optical characteristics. The lenses are formed precisely at desired locations on a wafer using a polymer-jet system in which hydrophobic effects define the lens diameter and surface tension creates a high-quality optical surface. To make the lenses, we defined hydrophilic circular regions at desired locations using photolithography to pattern a 0.2-pm thick Teflon (hydrophobic) layer on a quartz substrate, as shown in Figures 1 and 2. Then, using a polymer-microjet printing system (Figure 3), we dispense an exact amount of UV-curable polymer within hydrophilic circles to obtain microlenses having desired optical properties [ 13. Figure 4 shows that adjusting the volume of the UV-curable optical epoxy within a hydrophilic circle of a given diameter changes the curvature of the microlens. The step resolution of the microlens volume is determined by the average droplet size (~25pL) of the polymer-jet print head. This hybrid method enables us to define the locations and diameters of microlenses with a ±1 μm precision as well as to control the curvatures of the microlenses accurately

Optical switch using frequency-based addressing in a microelectromechanical systems array

Embodiments of the present invention provide structures for microelectromechanical systems (MEMS) that can be sensed, activated, controlled or otherwise addressed or made to respond by the application of forcing functions. In particular, an optical shutter structure suitable for use in an optical switch arrangement is disclosed. In one embodiment, an optical shutter or switch can be scaled and/or arranged to form arbitrary switch, multiplexer and/or demultiplexer configurations. In another embodiment of the present invention, an optical switch can include: a shutter; and a flexure coupled to the shutter, whereupon a vibration transmitted to the flexure when in the presence of a resonant frequency causes the shutter to move across an opening for the passage of an optical signal

Nanofabrication of 3 Dimensional Taper Structures for Nanofocusing Purposes

We have demonstrated experimentally a highly efficient on-chip three-dimensional (3D) linearly tapered metal-insulator-metal (MIM) nanoplasmonic photon compressor (3D NPC) with a final aperture size of 14 x 80nm^2. An optimized and linearly tapered MIM gap plasmon waveguide could theoretically reduce the excessive losses that would occur during nanofocusing processes. This nanofocusing concept has existed for some time, yet researchers had difficulty in realizing structures based on the concept because precisely fabricating the nanoscale waveguides that taper in three dimensions had been very challenging. In simulation study, this approach could enable nanofocusing into a 2 X 5nm^2 area with the coupling loss and maximum E^2 enhancement of 2.5 dB and 3.0x10^4, respectively. We fabricated the 3D NPC on a chip employing electron beam-induced deposition and demonstrated its highly localized light confinement using a two-photon photoluminescence (TPPL) technique. From the TPPL measurements, we experimentally estimated an intensity enhancement of 400 within a 14x80nm^2 crosssectional area and a coupling efficiency of -1.3dB (or 74% transmittance)

Quantitative analysis of a III-V tapered horn-shaped metal-clad nano-cavity as an on-chip light source

A horn-shaped metal-clad InGaAsP nano-cavity with sloped sidewalls is proposed as a platform for nanoscale light sources. The nano-cavity’s physical dimensions are 350 × 350 × 350 nm^3, and its mode volume is 0.5 (λ_0/n)^3. In our numerical simulations and quantitative analysis, we have shown that the sloped sidewalls reduce metallic absorption and improve resonant mode confinement; and adjusting their slope from 0 to 16° increased the Q factor from 150 to 900 and laser modulation 3dB bandwidth from 4.3 to 36 GHz. The lasing threshold current was expected to be 35 μA at 16°. In a simulated feasibility study, we demonstrate 60 Gbps modulated laser signal (5 fJ/bit), producing 20 μW output power at the 1.5 μm wavelength with injection current 100 μA, as an implementation of horn-shaped nano-cavity platform to the low power and ultra-fast on-chip nano-laser

Microfabricated torsional actuator using self-aligned plastic deformation

We describe microfabricated torsional actuators that are made using self-aligned plastic deformation in a batch process. The microactuators are formed in single-crystal silicon and driven by vertical comb-drives. Structures have been built that resonate at frequencies between 1.90 and 5.33 kHz achieving scanning angles up to 19.2 degrees with driving voltages of 40 V_(dc) plus 13 V_(ac). After continuous testing of 5 billion cycles at the maximum scanning angle, there appears to be no observable degradation or fatigue of the plastically deformed silicon tors ion bars. We present measured results obtained with MEMS scanning mirrors; the actuators may be useful for many other MEMS applications

Microfabricated Torsional Actuators Using Self-Aligned Plastic Deformation of Silicon

In this paper, we describe angular vertical-comb-drive torsional microactuators made in a new process that induces residual plastic deformation of single-crystal-silicon torsion bars. Critical dimensions of the vertically interdigitated moving-and fixed-comb actuators are self-aligned in the fabrication process and processed devices operate stably over a range of actuation voltages. We demonstrate MEMS scanning mirrors that resonate at 2.95kHz and achieve optical scan angles up to 19.2 degrees with driving voltages of 40V_(dc) plus 13V_(pp). After continuous testing of five billion cycles at the maximum scanning angle, we do not observe any signs of degradation in the plastically deformed silicon torsion bars