A5030035334- Terahertz technology and applications
- Spectroscopy and Laser Applications
- Semiconductor Quantum Structures and Devices
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- GaN-based semiconductor devices and materials
- Atmospheric Ozone and Climate
- Photonic and Optical Devices
- Porphyrin and Phthalocyanine Chemistry
- Advancements in Battery Materials
- Nonlinear Optical Materials Research
- ZnO doping and properties
- Cultural Heritage Materials Analysis
- Laser Design and Applications
- Semiconductor Lasers and Optical Devices
- Nonlinear Optical Materials Studies
- 2D Materials and Applications
- Advanced Fluorescence Microscopy Techniques
- Electron and X-Ray Spectroscopy Techniques
- Quantum Dots Synthesis And Properties
- Advanced Fiber Laser Technologies
- IoT and Edge/Fog Computing
- Supramolecular Chemistry and Complexes
- Phytochemistry and Biological Activities
- Laser Material Processing Techniques
Guru Ghasidas Vishwavidyalaya
2023
GNA University
2023
Chandigarh University
2017-2022
University of Central Florida
2016-2019
Central Forensic Science Laboratory
2019
Indian Institute of Science Education and Research Mohali
2017
Paul Drude Institute for Solid State Electronics
2011-2014
Université de Montpellier
2010-2013
Centre National de la Recherche Scientifique
2010-2013
Institut d'Électronique et des Systèmes
2011-2013
Currently, different competing waveguide and resonator concepts exist for terahertz quantum-cascade lasers (THz QCLs). We examine the continuous-wave (cw) performance of THz QCLs with single-plasmon (SP) metal-metal (MM) waveguides fabricated from same wafer. While SP are superior in terms output power, maximum operating temperature MM is typically much higher. For QCLs, we observed cw operation up to 73 K as compared 129 narrow (≤ 15 μm) QCLs. In latter case, single-mode a beam profile were...
Dye laser action has been achieved with a pulsed N2 as the pumping source. The dye pulses vary in length from 2 to 10 nsec for various dyes used and have tuned cover entire visible spectrum proper choice of cavity optics. system is capable, some dyes, repetition rates high 100 pulses/sec reasonably good efficiencies.
Local oscillators in terahertz heterodyne spectrometers have to be operated continuous-wave mode at precisely defined target frequencies. In particular, for advanced airborne instruments, several specifications such as operating temperature and cooling requirements are necessary considered. We developed a quantum-cascade laser (QCL) applicable local oscillator spectroscopy of the OI line 4.745 THz, which is particular interest astronomy. demonstrate distributed-feedback QCL up about 60 K,...
Compounds with polarizable π systems that are susceptible to attack nucleophiles at C–Hal (Hal = Cl, Br) bonds react Pd(PPh3)4 yield net oxidative addition. X-ray structures show the resulting Pd(PPh3)2Hal groups greatly reduce intermolecular π–π interactions. The Pd-functionalized dyes generally exhibit solution-like absorption spectra in films, whereas their Hal analogues features attributable aggregation.
Doped nanophosphor samples of ZnS:Mn, Co and Fe were prepared using a chemical precipitation method. Photoluminescence (PL) spectra obtained lifetime studies the nanophosphors carried out at room temperature. To best our knowledge, there are very few reports on photoluminescence investigations Co-doped or Fe-doped ZnS:Mn nanoparticles in literature. Furthermore, is no report luminescence shortening doped with impurity. Experimental results showed that considerable change X (X = Co, Fe). The...
We report on terahertz quantum-cascade lasers (THz QCLs) based first-order lateral distributed-feedback (lDFB) gratings, which exhibit continuous-wave operation, high output powers (>8 mW), and single-mode emission at 3.3-3.4 THz. A general method is presented to determine the coupling coefficients of gratings in terms coupled-mode theory, demonstrates that large strengths are obtained presence corrugated metal layers. The experimental spectra agreement with simulations lDFB cavities, take...
Cyanines with long conjugation length such as heptamethines are well known to have strong intramolecular and/or intermolecular interactions (i.e., ion paring and aggregation), which can affect their structures symmetry breaking) optical properties remarkably. In this paper, we report a covalently linked complementary cyanine complex of cationic anionic forming highly polarizable zwitterionic cyanine–cyanine salt. The effect the modification was studied in detail on both its electronic...
Pd(PPh<sub>3</sub>)<sub>2</sub>Cl groups hinder aggregation and afford promising solid-state NLO properties.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIron-57 Moessbauer spectroscopy of reduced cathodes in the lithium/iron disulfide battery system: evidence for superparamagnetismC. H. W. Jones, P. E. Kovacs, R. D. Sharma, and S. McMillanCite this: J. Phys. Chem. 1990, 94, 2, 832–836Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Published inissue 1 January 1990https://pubs.acs.org/doi/10.1021/j100365a059https://doi.org/10.1021/j100365a059research-articleACS...
We report on measurements of radiation transmission in the 0.220–0.325 THz frequency range through GaN quantum wells grown sapphire substrates at nitrogen and room temperatures. Significant enhancement transmitted beam intensity with applied voltage is found temperature. This effect explained by changes mobility two-dimensional electrons under electric bias. have clarified which physical mechanism modifies electron we suggest that voltage-controlled sub-terahertz can be used for development...
In this work, a new phosphonium-containing cationic polyelectrolyte (PE1) has been rationally designed and developed via facile click-chemistry type postfunctionalization, which can form complexes with highly polarizable anionic cyanines to significantly reduce the strong random cyanine–cyanine interactions (i.e., aggregation) in solid-state. This material design strategy enables an efficient translation of favorable molecular properties into macroscopic properties. One such exhibits very...
First results on epitaxial-side (epi-down) mounting of terahertz quantum-cascade lasers (QCLs) sapphire submounts using indium solder are presented. The single-plasmon ridge waveguide emit in the range 3.1–3.3 THz. An epi-down scheme for stressless assembly is realized, which provides enhanced heat dissipation at corresponding operating temperature and high stability against thermal cycling. conductance devices improved by 30%, maximum continuous-wave increased 10 K mounted achieving output...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIron-57 Moessbauer spectroscopy of the iron monosulfide cathode in lithium/iron battery systemC. H. W. Jones, P. E. Kovacs, R. D. Sharma, and S. McMillanCite this: J. Phys. Chem. 1990, 94, 10, 4325–4329Publication Date (Print):May 1, 1990Publication History Published online1 May 2002Published inissue 1 1990https://pubs.acs.org/doi/10.1021/j100373a082https://doi.org/10.1021/j100373a082research-articleACS PublicationsRequest reuse permissionsArticle...
We investigate the effect of stimulated emission on transport characteristics terahertz quantum-cascade lasers operating in a frequency range between 4.3 and 4.6 THz. The impact is varied by changing mirror losses via damaging one or two facets. In case voltage-driven measurements, reduction current density near onset observed for facet-damaged as compared to original one. measurements are qualitative agreement with results numerical simulations including emission.
We investigate the effect of post-growth rapid thermal annealing (RTA) on transport and lasing characteristics terahertz quantum-cascade lasers (THz QCLs) operating in a frequency range between 4.88 4.94 THz. The emission frequencies are blue shifted by about 80 GHz after RTA, which is attributed to shift gain maximum higher due composition grading at interfaces quantum wells barriers annealed wafer pieces. optical output power THz QCLs reduced, explained broadening levels process.
We report measurements of the pulsed and dc current-voltage characteristics AlGaN/GaN high--electron-mobility transistors as functions geometry, temperature (from 300 down to 15 K), operating conditions.An increase in drain current with shortening pulse width from 1 µs 400 ns is found be significant at room whilst this behavior inverted or even removed 77 K temperatures.
We investigate the relative transmission and effective gain of a two-dimensional electron gas (2DEG) in terahertz (THz) frequency domain. The position THz source, device, detector is numerically simulated order to obtain an optimized experimental configuration. effect variation polarization incident beam, geometries devices investigated. inter-digitated finger (IDF) structures device under investigation show maximum direct configuration which attributed metallic polarizing nature IDFs,...