Ga+ beam lithography for suspended lateral beams and nanowires

The authors demonstrate the fabrication of suspended nanowires and doubly clamped beams by using a focused ion beam implanted Ga etch mask followed by an inductively coupled plasma reactive ion etching of silicon. This method will demonstrate how a two-step, completely dry fabrication sequence can be tuned to generate nanomechanical structures on either silicon substrates or silicon on insulator (SOI). This method was used to generate lateral nanowires suspended between 2 µm scaled structures with lengths up to 16 µm and widths down to 40 nm on a silicon substrate. The authors also fabricate 10 µm long doubly clamped beams on SOIs that are 20 nm thick and a minimum of 150 nm wide. In situ electrical measurements of the beams demonstrate a reduction of resistivity from > 37.5 Ω cm down to 0.25 Ω cm. Transmission electron microscopy for quantifying both surface roughness and crystallinity of the suspended nanowires was performed. Finally, a dose array for repeatable fabrication of a desired beam width was also experimentally determined

Wafer-bonded single-crystal silicon slot waveguides and ring resonators

We fabricated horizontal Si slot waveguides with a 25 nm SiO2 slot layer by bonding thin Si-on-insulator wafers. After removing the Si substrate and buried oxide from one side of the bonded structure, grating-coupled waveguides and ring resonators were partially etched into the Si/SiO2/Si device layers. The gratings exhibit efficiencies of up to 23% at 1550 nm and the ring resonators were measured to have loaded quality factors near 42 000 for the lowest-order transverse-electric mode, corresponding to a propagation loss of 15 dB/cm. The leaky lowest-order transverse-magnetic mode was also observed with a propagation loss of 44 dB/cm

Participatory Mapping of Mid-Holocene Anthropogenic Landscapes in Guyana with Kite Aerial Photography

The nature and degree of human modifications of humid tropical forests in Amazonia have been widely debated over the past two decades Many regions provide significant evidence of late Holocene anthropogenic influence by settled populations but the antiquity of human interventions is still poorly understood due to a lack of earlier archaeological sites across the broad region particularly pertaining to the mid-Holocene Here we report on Amerindian occupations spanning the period from ca 6000-3000 BP along the middle Berbice River Guyana including early evidence in Amazonia of cultural practices widely considered indicative of settled villages notably terra preta or black earth soils mound construction and ceramic technology These more settled occupations of the mid-Holocene initiated a trajectory of landscape domestication extending into historical times including larger-scale late Holocene social formations Collaborative research with local indigenous communities including archaeological excavations landscape mapping using kite based aerial photography and three-dimensional photogrammetry was designed to promote the decolonization of archaeological knowledge production and encourage indigenous ownership of Amerindian history and cultural heritage in Guyan

Castleberry v. Branscum: A Divided Texas Supreme Court Increases Shareholder Liability for Corporate Contractual Obligations.

Abstract Forthcoming

Castleberry v. Branscum: A Divided Texas Supreme Court Increases Shareholder Liability for Corporate Contractual Obligations.

Abstract Forthcoming

An RF-powered micro-reactor for the detection of astrobiological target molecules on planetary bodies

We describe a sample-processing micro-reactor that utilizes 60 GHz RF radiation with approximately 730 mW of output power. The instrument design and performance characterization are described and then illustrated with modeling and experimental studies. The micro-reactor's efficiency on affecting hydrolysis of chemical bonds similar to those within large complex molecules was demonstrated: a disaccharide—sucrose—was hydrolyzed completely under micro-reactor conditions. The products of the micro-reactor-facilitated hydrolysis were analyzed using mass spectroscopy and proton nuclear magnetic resonance analytical techniques

Advanced silicon processing for active planar photonic devices

Using high quality, anisotropically etched Si waveguides bonded to InGaAsP, the authors demonstrate a hybrid laser, whose optical profile overlaps both Si and III-V regions. Continuous wave laser operation was obtained up to 45 °C, with single facet power as high as 12.7 mW at 15 °C. Planar Si optical resonators with Q = 4.8 × 10^6 are also demonstrated. By using a SF_6/C_(4)F_8 reactive ion etch, followed by H_(2)SO_4/HF surface treatment and oxygen plasma oxide, the optical losses due to the waveguide and the bonding interface are minimized. Changes of optical confinement in the silicon are observed due to waveguide width variation

Programmable Spectral Source and Design Tool for 3D Imaging Using Complementary Bandpass Filters

An endoscopic illumination system for illuminating a subject for stereoscopic image capture, includes a light source which outputs light; a first complementary multiband bandpass filter (CMBF) and a second CMBF, the first and second CMBFs being situated in first and second light paths, respectively, where the first CMBF and the second CMBF filter the light incident thereupon to output filtered light; and a camera which captures video images of the subject and generates corresponding video information, the camera receiving light reflected from the subject and passing through a pupil CMBF pair and a detection lens. The pupil CMBF includes a first pupil CMBF and a second pupil CMBF, the first pupil CMBF being identical to the first CMBF and the second pupil CMBF being identical to the second CMBF, and the detection lens includes one unpartitioned section that covers both the first pupil CMBF and the second pupil CMBF

Hybrid Electrically Pumped Evanescent Si/InGaAsP Lasers

Hybrid Si/InGaAsP Fabry-Perot evanescent lasers are fabricated via wafer bonding. Compared with previous similar devices, the current threshold density, turn-on voltage, output power and slope efficiency are all improved. Images show modal confinement to Silicon