Author
S. Dutta Gupta
Other affiliations: University of Electro-Communications
Bio: S. Dutta Gupta is an academic researcher from University of Hyderabad. The author has contributed to research in topics: Surface plasmon & Plasmon. The author has an hindex of 21, co-authored 91 publications receiving 1565 citations. Previous affiliations of S. Dutta Gupta include University of Electro-Communications.
Papers published on a yearly basis
Papers
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TL;DR: In this article, the spontaneous emission of a cesium atom in the vicinity of a subwavelength-diameter fiber was studied and it was shown that the confinement of the guided modes and the degeneracy of the excited and ground states substantially affect spontaneous emission process.
Abstract: We study the spontaneous emission of a cesium atom in the vicinity of a subwavelength-diameter fiber. We show that the confinement of the guided modes and the degeneracy of the excited and ground states substantially affect the spontaneous emission process. We demonstrate that different magnetic sublevels have different decay rates. When the fiber radius is about $200\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, a significant fraction (up to 28%) of spontaneous emission by the atom can be channeled into guided modes. Our results may find applications for developing nanoprobes for atoms and efficient couplers for subwavelength-diameter fibers.
233 citations
TL;DR: In this article, the authors demonstrate a substantial radiative exchange between distant atoms mediated by the guided modes of the nanofiber, which leads to increased and decreased lifetimes of the subradiant and superradiant states, respectively.
Abstract: We study spontaneous emission from a pair of two-level atoms near a nanofiber. We demonstrate a substantial radiative exchange between distant atoms mediated by the guided modes of the nanofiber. The exchange is shown to lead to increased and decreased lifetimes of the subradiant and superradiant states, respectively. Our analysis is based on the full quantization of both the radiation and guided modes of the fiber in the framework of the Heisenberg-Langevin theory and the master equation formalism.
146 citations
TL;DR: The versatility provided by metal-dielectric composites is exploited to demonstrate controllable coherent perfect absorption (CPA) or anti-lasing in a slab of heterogeneous medium to demonstrate the controllability of the CPA frequency to the extent of having the same at two distinct frequencies even in presence of dispersion.
Abstract: We exploit the versatility provided by metal-dielectric composites to demonstrate controllable coherent perfect absorption (CPA) or anti-lasing in a slab of heterogeneous medium The slab is illuminated by coherent light from both sides, at the same angle of incidence and the conditions required for CPA are investigated as a function of the different system parameters Our calculations clearly elucidate the role of absorption as a necessary prerequisite for CPA We further demonstrate the controllability of the CPA frequency to the extent of having the same at two distinct frequencies even in presence of dispersion, rendering the realization of anti-lasers more flexible
106 citations
TL;DR: The nonlinear susceptibilities of a heterogeneous medium are calculated by using a generalization of the standard T-matrix approach and results for the susceptibilities for degenerate and nondegenerate four-wave mixing and nonlinear absorption are obtained.
Abstract: The nonlinear susceptibilities of a heterogeneous medium are calculated by using a generalization of the standard T-matrix approach. Results for the susceptibilities for degenerate and nondegenerate four-wave mixing and nonlinear absorption are obtained. These are evaluated explicitly for a medium with nonlinear spherical grains. The role of various resonances in the generation of the signals is discussed. In the special cases of low concentration of inhomogeneities, present results agree with those of Flytzanis and co-workers [Opt. Lett. 9, 344 (1984); 10, 511 (1985); J. Opt. Soc. Am. B 4, 5 (1987)].
93 citations
TL;DR: In this paper, the authors consider the feasibility of controlling the energy transfer between an unexcited and an excited atom using microcavities and show that the excitation transfer probability is related to the strength of the dipole-dipole interaction.
Abstract: We consider the feasibility of controlling the energy transfer between an unexcited and an excited atom using microcavities. The excitation-transfer probability is related to the strength of the dipole-dipole interaction and thus the excitation-transfer rates could be increased by enhancing the dipole-dipole interaction. We demonstrate this enhancement with an explicit three-dimensional calculation for a metallic cavity, which we characterize with a realistic dielectric function. We also demonstrate the shifts in cavity resonances from their ideal positions $m\ensuremath{\lambda}/2$ ($m$ is an integer and \ensuremath{\lambda} is the wavelength).
83 citations
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TL;DR: This review describes recent advances in the synthesis of biomolecule-nanoparticle/nanorod hybrid systems and the application of such assemblies in the generation of 2D and 3D ordered structures in solutions and on surfaces.
Abstract: Nanomaterials, such as metal or semiconductor nanoparticles and nanorods, exhibit similar dimensions to those of biomolecules, such as proteins (enzymes, antigens, antibodies) or DNA. The integration of nanoparticles, which exhibit unique electronic, photonic, and catalytic properties, with biomaterials, which display unique recognition, catalytic, and inhibition properties, yields novel hybrid nanobiomaterials of synergetic properties and functions. This review describes recent advances in the synthesis of biomolecule-nanoparticle/nanorod hybrid systems and the application of such assemblies in the generation of 2D and 3D ordered structures in solutions and on surfaces. Particular emphasis is directed to the use of biomolecule-nanoparticle (metallic or semiconductive) assemblies for bioanalytical applications and for the fabrication of bioelectronic devices.
2,334 citations
TL;DR: In this article, the time dependence of ρ11, ρ22 and ρ12 under steady-state conditions was analyzed under a light field interaction V = -μ12Ee iωt + c.c.
Abstract: (b) Write out the equations for the time dependence of ρ11, ρ22, ρ12 and ρ21 assuming that a light field interaction V = -μ12Ee iωt + c.c. couples only levels |1> and |2>, and that the excited levels exhibit spontaneous decay. (8 marks) (c) Under steady-state conditions, find the ratio of populations in states |2> and |3>. (3 marks) (d) Find the slowly varying amplitude ̃ ρ 12 of the polarization ρ12 = ̃ ρ 12e iωt . (6 marks) (e) In the limiting case that no decay is possible from intermediate level |3>, what is the ground state population ρ11(∞)? (2 marks) 2. (15 marks total) In a 2-level atom system subjected to a strong field, dressed states are created in the form |D1(n)> = sin θ |1,n> + cos θ |2,n-1> |D2(n)> = cos θ |1,n> sin θ |2,n-1>
1,872 citations
Journal Article•
TL;DR: Squeezed states of the electromagnetic field have been generated by nondegenerate four-wave mixing due to Na atoms in an optical cavity by measuring the total noise level in the deamplified quadrature below the vacuum noise level.
Abstract: Squeezed states of the electromagnetic field have been generated by nondegenerate four-wave mixing due to Na atoms in an optical cavity. The optical noise in the cavity, comprised of primarily vacuum fluctuations and a small component of spontaneous emission from the pumped Na atoms, is amplified in one quadrature of the optical field and deamplified in the other quadrature. These quadrature components are measured with a balanced homodyne detector. The total noise level in the deamplified quadrature drops below the vacuum noise level.
1,217 citations
TL;DR: The Jaynes-Cummings model was used to examine the classical aspects of spontaneous emission and reveal the existence of Rabi oscillations in atomic excitation probabilities for fields with sharply defined energy as mentioned in this paper.
Abstract: The Jaynes-Cummings model (JCM), a soluble fully quantum mechanical model of an atom in a field, was first used (in 1963) to examine the classical aspects of spontaneous emission and to reveal the existence of Rabi oscillations in atomic excitation probabilities for fields with sharply defined energy (or photon number). For fields having a statistical distributions of photon numbers the oscillations collapse to an expected steady value. In 1980 it was discovered that with appropriate initial conditions (e.g. a near-classical field), the Rabi oscillations would eventually revive, only to collapse and revive repeatedly in a complicated pattern. The existence of these revivals, present in the analytic solutions of the JCM, provided direct evidence for discreteness of field excitation (photons) and hence for the truly quantum nature of radiation. Subsequent study revealed further non-classical properties of the JCM field, such as a tendency of the photons to antibunch. Within the last two years it ha...
1,086 citations
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TL;DR: The last volume of the Progress in Optics series as discussed by the authors contains seven chapters on widely diverging topics, written by well-known authorities in their fields, including laser selective photophysics and photochemistry, laser phase profile generation, laser beamforming, and laser laser light emission from high-current surface spark discharges.
Abstract: Have you ever felt that the very title, Progress in Optics, conjured an image in your mind? Don’t you see a row of handsomely printed books, bearing the editorial stamp of one of the most brilliant members of the optics community, and chronicling the field of optics since the invention of the laser? If so, you are certain to move the bookend to make room for Volume 16, the latest of this series. It contains seven chapters on widely diverging topics, written by well-known authorities in their fields. These are: 1) Laser Selective Photophysics and Photochemistry by V. S. Letokhov, 2) Recent Advances in Phase Profiles (sic) Generation by J. J. Clair and C. I. Abitbol, 3 ) Computer-Generated Holograms: Techniques and Applications by W.-H. Lee, 4) Speckle Interferometry by A. E. Ennos, 5 ) Deformation Invariant, Space-Variant Optical Pattern Recognition by D. Casasent and D. Psaltis, 6) Light Emission from High-Current Surface-Spark Discharges by R. E. Beverly, and 7) Semiclassical Radiation Theory within a QuantumMechanical Framework by I. R. Senitzkt. The breadth of topic matter spanned by these chapters makes it impossible, for this reviewer at least, to pass judgement on the comprehensiveness, relevance, and completeness of every chapter. With an editorial board as prominent as that of Progress in Optics, however, it seems hardly likely that such comments should be necessary. It should certainly be possible to take the authority of each author as credible. The only remaining judgment to be made on these chapters is their readability. In short, what are they like to read? The first sentence of the first chapter greets the eye with an obvious typographical error: “The creation of coherent laser light source, that have tunable radiation, opened the . . . .” Two pages later we find: “When two types of atoms or molecules of different isotopic composition ( A and B ) have even one spectral line that does not overlap with others, it is pos-
1,071 citations