1,969 research outputs found
Octave spanning mid-infrared frequency comb generation in silicon nanophotonic wire waveguides
Impact of Strain on Drain Current and Threshold Voltage of Nanoscale Double Gate Tunnel Field Effect Transistor: Theoretical Investigation and Analysis
Tunnel field effect transistor (TFET) devices are attractive as they show
good scalability and have very low leakage current. However they suffer from
low on-current and high threshold voltage. In order to employ the TFET for
circuit applications, these problems need to be tackled. In this paper, a novel
lateral strained double-gate TFET (SDGTFET) is presented. Using device
simulation, we show that the SDGTFET has a higher on-current, low leakage, low
threshold voltage, excellent subthreshold slope, and good short channel effects
and also meets important ITRS guidelines.Comment: http://web.iitd.ac.in/~mamidal
Tunneling Ionization Rates from Arbitrary Potential Wells
We present a practical numerical technique for calculating tunneling
ionization rates from arbitrary 1-D potential wells in the presence of a linear
external potential by determining the widths of the resonances in the spectral
density, rho(E), adiabatically connected to the field-free bound states. While
this technique applies to more general external potentials, we focus on the
ionization of electrons from atoms and molecules by DC electric fields, as this
has an important and immediate impact on the understanding of the multiphoton
ionization of molecules in strong laser fields.Comment: 13 pages, 7 figures, LaTe
THE RELATIONSHIP OF STRUCTURE AND PLANT-GROWTH ACTIVITY OF SUBSTITUTED BENZOIC AND PHENOXYACETIC ACIDS
Broadband laser cooling of trapped atoms with ultrafast pulses
We demonstrate broadband laser cooling of atomic ions in an rf trap using
ultrafast pulses from a modelocked laser. The temperature of a single ion is
measured by observing the size of a time-averaged image of the ion in the known
harmonic trap potential. While the lowest observed temperature was only about 1
K, this method efficiently cools very hot atoms and can sufficiently localize
trapped atoms to produce near diffraction-limited atomic images
Astronomical spectrograph calibration with broad-spectrum frequency combs
Broadband femtosecond-laser frequency combs are filtered to
spectrographically resolvable frequency-mode spacing, and the limitations of
using cavities for spectral filtering are considered. Data and theory are used
to show implications to spectrographic calibration of high-resolution,
astronomical spectrometers
Slow Light in Doppler Broadened Two level Systems
We show that the propagation of light in a Doppler broadened medium can be
slowed down considerably eventhough such medium exhibits very flat dispersion.
The slowing down is achieved by the application of a saturating counter
propagating beam that produces a hole in the inhomogeneous line shape. In
atomic vapors, we calculate group indices of the order of 10^3. The
calculations include all coherence effects.Comment: 6 pages, 5 figure
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