0000000000535138

AUTHOR

Santosh Kumar

showing 3 related works from this author

Resonant laser spectroscopy of localized excitons in monolayer WSe_2

2016

Coherent quantum control and resonance fluorescence of few-level quantum systems is integral for quantum technologies. Here we perform resonance and near-resonance excitation of three-dimensionally confined excitons in monolayer WSe2 to reveal near-ideal single-photon fluorescence with count rates up to 3 MHz. Using high-resolution photoluminescence excitation spectroscopy of the localized excitons, we uncover a weakly fluorescent exciton state ∼5  meV blue shifted from the ground-state exciton, providing important information to unravel the precise nature of quantum states. Successful demonstration of resonance fluorescence paves the way to probe the localized exciton coherence in two-dime…

Semiconductor luminescence equationsCondensed Matter::OtherChemistryExciton02 engineering and technologyCondensed Matter::Mesoscopic Systems and Quantum Hall Effect021001 nanoscience & nanotechnology01 natural sciencesAtomic and Molecular Physics and Optics3. Good healthElectronic Optical and Magnetic MaterialsQuantum technologyCondensed Matter::Materials ScienceResonance fluorescence0103 physical sciencesPhotoluminescence excitationAtomic physicsQuantum-optical spectroscopy010306 general physics0210 nano-technologySpectroscopyBiexcitonOptica
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Ligand Diversity of Human and Chimpanzee CYP3A4: Activation of Human CYP3A4 by Lithocholic Acid Results from Positive SelectionS⃞

2009

For currently unknown reasons, the evolution of CYP3A4 underwent acceleration in the human lineage after the split from chimpanzee. We investigated the significance of this event by comparing Escherichia coli-expressed CYP3A4 from humans, chimpanzee, and their most recent common ancestor. The expression level of chimpanzee CYP3A4 was ∼50% of the human CYP3A4, whereas ancestral CYP3A4 did not express in E. coli. Steady-state kinetic analysis with 7-benzyloxyquinoline, 7-benzyloxy-4-(trifluoromethyl)coumarin (7-BFC), and testosterone showed no significant differences between human and chimpanzee CYP3A4. Upon addition of α-naphthoflavone (25 μM), human CYP3A4 showed a slightly decreased substr…

Most recent common ancestorModels MolecularLithocholic acidLineage (genetic)Pan troglodytesmedicine.drug_classPharmaceutical ScienceLigandsIsozymechemistry.chemical_compoundSpecies SpecificityCoumarinsmedicineAnimalsCytochrome P-450 CYP3AHumansPharmacologychemistry.chemical_classificationBinding SitesbiologyBile acidCYP3A4Cytochrome P450ArticlesAmino acidEnzyme ActivationchemistryBiochemistrybiology.proteinLithocholic AcidSteroids
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Nanoscale strain-engineering and optics of quantum emitters in a two-dimensional semiconductor

2017

We present deterministic fabrication of a two-dimensional lattice of quantum emitters in an atomically thin semiconductor. Resonant laser spectroscopy of these emitters reveals localized exciton states that exhibit stable, bright and high-purity single photon emission.

0301 basic medicineSemiconductor luminescence equationsMaterials scienceFabricationbusiness.industryExcitonPhysics::Optics02 engineering and technology021001 nanoscience & nanotechnology03 medical and health sciences030104 developmental biologyStrain engineeringSemiconductorPhysics::Accelerator PhysicsOptoelectronics0210 nano-technologySpectroscopybusinessQuantumElectron-beam lithographyConference on Lasers and Electro-Optics
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