A5041073669- Quantum Dots Synthesis And Properties
- Plasmonic and Surface Plasmon Research
- Photonic Crystals and Applications
- Neurobiology and Insect Physiology Research
- Gold and Silver Nanoparticles Synthesis and Applications
- Metamaterials and Metasurfaces Applications
- Coral and Marine Ecosystems Studies
- Chalcogenide Semiconductor Thin Films
- Perovskite Materials and Applications
- Amphibian and Reptile Biology
- Food Industry and Aquatic Biology
- Nonlinear Optical Materials Studies
- Marine and coastal plant biology
- Semiconductor Quantum Structures and Devices
- Spectroscopy Techniques in Biomedical and Chemical Research
- Quantum optics and atomic interactions
- Advanced Optical Sensing Technologies
- Laser-Matter Interactions and Applications
- Advanced Scientific Research Methods
- Crustacean biology and ecology
- Photonic and Optical Devices
- Photonic Crystal and Fiber Optics
- Nanocluster Synthesis and Applications
- Fern and Epiphyte Biology
- Advanced Fiber Laser Technologies
Indian Institute of Technology Kanpur
2021-2023
Weizmann Institute of Science
2018-2023
Tata Institute of Fundamental Research
2013-2016
Magnetic field control of light is among the most intriguing methods for modulation intensity and polarization on sub-nanosecond timescales. The implementation in nanostructured hybrid materials provides a remarkable increase magneto-optical effects. However, so far only enhancement already known effects has been demonstrated such materials. Here we postulate novel phenomenon that originates solely from suitably designed metal-dielectric material, so-called magneto-plasmonic crystal. In this...
Many oceanic prey animals use transparent bodies to avoid detection. However, conspicuous eye pigments, required for vision, compromise the organisms' ability remain unseen. We report discovery of a reflector overlying pigments in larval decapod crustaceans and show how it is tuned render organisms inconspicuous against background. The ultracompact constructed from photonic glass crystalline isoxanthopterin nanospheres. nanospheres' size ordering are modulated tune reflectance deep blue...
A fundamental question regarding light scattering is how whiteness, generated from multiple scattering, can be obtained thin layers of materials. This challenge arises the phenomenon optical crowding, whereby, for scatterers packed with filling fractions higher than ~30%, reflectance drastically reduced due to near-field coupling between scatterers. Here we show that extreme birefringence isoxanthopterin nanospheres overcomes crowding effects, enabling and brilliant whiteness ultra-thin...
The spectral properties of the transverse magneto-optical Kerr effect (TMOKE) in periodic metal–dielectric hybrid structures are studied, particular with respect to achievable magnitude. It is shown that TMOKE sensitive activity bismuth-substituted rare-earth iron garnet, which used as a dielectric material investigated structures. For samples larger Bi substitution level and, consequently, gyration constant, magnitude increases and reaches 13% case Bi1.8Lu1.2Fe3.6Al1.4O12 magnetic film....
Metasurfaces with sub-wavelength features are useful in modulating the phase, amplitude or polarization of electromagnetic fields. While several applications reported for light manipulation and control, sharp phase changes would be enhancing beam shifts at reflection from a metasurface. In designed periodic patterns on metal film, surface plasmon resonance, we demonstrate Goos-Hanchen shift order 70 times incident wavelength angular hundred microradians. We have using rigorous coupled wave...
Understanding exciton-exciton interaction in multiply excited nanocrystals is crucial to their utilization as functional materials. Yet, for lead halide perovskite nanocrystals, which are promising candidates nanocrystal-based technologies, numerous contradicting values have been reported the strength and sign of interaction. In this work, we unambiguously determine biexciton binding energy single cesium at room temperature. This enabled by recently introduced single-photon avalanche diode...
Multiply-excited states in semiconductor quantum dots feature intriguing physics and play a crucial role nanocrystal-based technologies. While photoluminescence provides natural probe to investigate these states, room temperature single-particle spectroscopy of their emission has so far proved elusive due the temporal spectral overlap with from singly-excited charged states. Here we introduce biexciton heralded spectroscopy, enabled by single-photon avalanche diode array based spectrometer....
The magneto-optical properties of a hybrid metal-dielectric structure consisting one-dimensional gold grating on top magnetic waveguide layer are studied experimentally and theoretically. It is demonstrated that field applied in the longitudinal configuration (in plane film perpendicular to slits grating) modifies distribution optical modes thus changes mode excitation conditions. In far field, this manifests alteration transmittance or reflectance when becomes magnetized. This effect shown...
Measurements of photon temporal correlations have been the mainstay experiments in quantum optics. Over past several decades, advancements detector technologies supported further extending correlation techniques to give rise novel spectroscopy and imaging methods. This Perspective reviews evolution these from autocorrelations through multidimensional imaging. State-of-the-art single-photon are discussed, highlighting main challenges unique current perspective usher a new generation modalities.
Plasmonic quasicrystals (PlQCs), by integrating the properties of (rotational symmetry and long range ordering but lack translational symmetry) surface plasmon polariton mediated effects, offer several advantages over plasmonic crystals (PlCs). For example, in PlQCs one could have broadband, polarization independent response. However, large area patterning electron beam lithography requires precise lattice coordinates as well a practical way to design structures for specific spectral We...
Many animals undergo changes in functional colors during development, requiring the replacement of integument or pigment cells. A classic example defensive color switching is found hatchling lizards, which use conspicuous tail to deflect predator attacks away from vital organs. These usually fade concealing ontogeny. Here, we show that ontogenetic blue-to-brown change Acanthodactylus beershebensis lizards results changing optical properties single types developing chromatophore The blue...
Excitons in colloidal semiconductor nanoplatelets (NPLs) are weakly confined the lateral dimensions. This results significantly smaller Auger rates and, consequently, larger biexciton quantum yields, when compared to spherical dots (QDs). Here we report a study of temperature dependence rate individual CdSe/CdS core–shell NPLs, through measurement time-gated second-order photon correlations photoluminescence. We also utilize this method directly estimate single-exciton radiative rate. find...
We present the first calculation of Goos-Hänchen shifts in context nonlinear generation fields. specifically concentrate on second harmonic generated at metallic surfaces. At surfaces primarily arises from discontinuities field which not only result large but also significant harmonic. Our results can be extended to other like angular and Fedorov-Imbert shifts.
Spherulites are birefringent sturctures with spherical symmetry, which typically observed in crystallized polymers. We compute the band structure of opals made close-packed assemblies highly spherulites. demonstrate that spherulitic birefringence constituent spheres does not affect symmetries an opal, and yet significantly affects dispersion eigenmodes, leading to new pseudogaps sections structure, consequently enhanced reflectivity.
High precision measurements of optical beam shifts are important in various fields including sensing, atomic force microscopy, and measuring at interfaces. Sub-micron generally measured by indirect techniques such as weak measurements. We demonstrate a straightforward robust measurement scheme for the shift, based on scanning quadrant photodiode (QPD) that is biased using low noise electronic circuit. The shift with respect to reference co-propagating signal beam. Thus, readout directly...
Abstract Many animals undergo dramatic changes in colour during development 1,2 . Changes predation risk ontogeny are associated with spectacular switches defensive colours, typically involving the replacement of skin or production new pigment cells 3 Ontogenetic systems ideal models for understanding evolution and formation mechanisms animal which remain largely enigmatic 2 We show that switching lizards arises by reorganization a single photonic system, as an incidental by-product...
Recent studies of optical reflectors as part the vision apparatus in eyes decapod crustaceans revealed assemblies nanoscale spherulites - spherical core-shell nanoparticles with radial birefringence. Simulations performed on system highlighted advantages anisotropy enhancing functionality these structures. So far, calculations nanoparticle properties have relied refractive indices obtained using ab-initio calculations. Here we describe a direct measurement tangential index spherulites, which...
Semiconductor nanocrystals feature multiply-excited states that display intriguing physics and significantly impact nanocrystal-based technologies. Fluorescence supplies a natural probe to investigate these states. Still, direct observation of multiexciton fluorescence has proved elusive existing spectroscopy techniques. Heralded Spectroscopy is new tool based on breakthrough single-particle, single-photon, sub-nanosecond spectrometer utilizes temporal photon correlations isolate emission....
Supercontinuum generation using photonic crystal fibers is a useful technique to generate light spanning broad wavelength range, femtosecond laser pulses. For some applications, one may desire higher power density at specific wavelengths. Increasing the pump results primarily in further broadening of output spectrum and not particularly for this purpose. In paper we demonstrate that by applying periodic spectral phase modulation input pulse shaper, energy supercontinuum can be enhanced...
We characterize a reflector in the eye of <italic>shrimp L. vannamei</italic>, which likely acts as camouflage device to conceal pigments largely transparent animal.
Understanding exciton-exciton interaction in multiply-excited nanocrystals is crucial to their utilization as functional materials. Yet, for lead halide perovskite nanocrystals, which are promising candidates nanocrystal-based technologies, numerous contradicting values have been reported the strength and sign of interaction. In this work we unambiguously determine biexciton binding energy single cesium at room temperature. This enabled by recently introduced SPAD array spectrometer, capable...