Bell Labs

About: Bell Labs is a based out in . It is known for research contribution in the topics: Laser & Optical fiber. The organization has 36499 authors who have published 59862 publications receiving 3190823 citations. The organization is also known as: Bell Laboratories & AT&T Bell Laboratories.

Linear Pulse Propagation in an Absorbing Medium

Abstract: The pulse velocity in the linear regime in samples of GaP: N with a laser tuned to the bound $A$-exciton line is measured with use of a picosecond time-of-flight technique. The pulse is seen to propagate through the material with little pulse-shape distortion, and with an envelope velocity given by the group velocity even when the group velocity exceeds 3\ifmmode\times\else\texttimes\fi{}${10}^{10}$ cm/sec, $\mathrm{equals}\ifmmode\pm\else\textpm\fi{}\ensuremath{\infty}$, or becomes negative. The results verify the predictions of Garrett and McCumber.

Force generation of organelle transport measured in vivo by an infrared laser trap.

Abstract: Organelle transport along microtubules is believed to be mediated by organelle-associated force-generating molecules. Two classes of microtubule-based organelle motors have been identified: kinesin and cytoplasmic dynein. To correlate the mechanochemical basis of force generation with the in vivo behaviour of organelles, it is important to quantify the force needed to propel an organelle along microtubules and to determine the force generated by a single motor molecule. Measurements of force generation are possible under selected conditions in vitro, but are much more difficult using intact or reactivated cells. Here we combine a useful model system for the study of organelle transport, the giant amoeba Reticulomyxa, with a novel technique for the non-invasive manipulation of and force application to subcellular components, which is based on a gradient-force optical trap, also referred to as 'optical tweezers'. We demonstrate the feasibility of using controlled manipulation of actively translocating organelles to measure direct force. We have determined the force driving a single organelle along microtubules, allowing us to estimate the force generated by a single motor to be 2.6 x 10(-7) dynes.

Large-Lattice-Relaxation Model for Persistent Photoconductivity in Compound Semiconductors

Abstract: A new model, based on an extremely strong coupling between the electronic and vibrational systems of certain defect centers, is proposed to explain the phenomenon of persistent photoconductivity observed in some compound semiconductors. The model is supported by data on donor-related defects in $n$-type ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ which exhibit the features characteristic of this effect: a very large Stokes shift (thermal depth, \ensuremath{\sim}0.1 eV; optical depth, \ensuremath{\sim}1.2 eV); and a very small (${10}^{\ensuremath{-}30}$ ${\mathrm{cm}}^{2}$), thermally activated, electron-capture cross section at temperatures below 77 K.

Unreeling netflix: Understanding and improving multi-CDN movie delivery

Abstract: Netflix is the leading provider of on-demand Internet video streaming in the US and Canada, accounting for 29.7% of the peak downstream traffic in US. Understanding the Netflix architecture and its performance can shed light on how to best optimize its design as well as on the design of similar on-demand streaming services. In this paper, we perform a measurement study of Netflix to uncover its architecture and service strategy. We find that Netflix employs a blend of data centers and Content Delivery Networks (CDNs) for content distribution. We also perform active measurements of the three CDNs employed by Netflix to quantify the video delivery bandwidth available to users across the US. Finally, as improvements to Netflix's current CDN assignment strategy, we propose a measurement-based adaptive CDN selection strategy and a multiple-CDN-based video delivery strategy, and demonstrate their potentials in significantly increasing user's average bandwidth.

Smectic liquid crystals

Abstract: The use of a certain class of liquid crystal materials that exhibit a smectic C phase allows the production of a bistable liquid crystal display element. Such bistable display elements promote the use of matrix addressing for liquid crystal based elements in a display.