P. K. Bhattacharya

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Time-resolved differential transmission measurements of self-assembled In0.4Ga0.6As quantum dots clearly indicate a phonon bottleneck between the n = 2 and n = 1 electronic levels. The key to this observation is the generation of electrons in dots where there are no holes so that electron-hole scattering does not mask the bottleneck. We use a simple carrier(More)
Three-dimensional multicomponent plasmas composed of species with very different masses support a new branch of charge-density fluctuations known as acoustic plasmons. Here, we report on an ultrafast optical method to generate and probe coherent states of acoustic plasmons in a slab of GaAs, which relies on strong photoexcitation to create a large(More)
We examine theoretically and experimentally the properties of two electrooptic devices based on quantum confined Stark effect of excitonic transitions. These two devices are shown to be critical in implementation of the Hopfield model as well as other neural type networks for associative memories. P-i(multiquantum wells)-n structures using GaAs/AlGaAs(More)
A monolithically integrated guided-wave modulator has been realized by using molecular-beam epitaxial regrowth and ion-milling techniques. The guiding and modulating regions consist, respectively, of In-doped GaAs and GaAs/In(0.34)Ga(0.66)As strained-layer multiquantum wells. Modulation is achieved by field-enhanced electroabsorption in the multiquantum(More)
Here we present a novel hyperpolarization method, Chemical Reaction-Induced Multi-molecular Polarization (CRIMP), which could be applied to the study of several in vivo processes simultaneously including glycolysis, TCA cycle, fatty acid synthesis and pH mapping. Through the use of non-enzymatic decarboxylation, we generate four hyperpolarized imaging(More)
The authors examine experimentally and theoretically two devices based on III-V technology, which are critical in the implementation of the Hopfield model as well as other neural type networks for associative memories. The devices are based on Stark effect of excitonic transitions. P-i (multiquantum wells)-n structures using GaAs/AlGaAs provide a(More)