Vijay S. Tripathi

Learn More
We report high performance infrared sensors that are based on intersubband transitions in nanoscale self-assembled quantum dots combined with a microcavity resonator made with a high-index-contrast two-dimensional photonic crystal. The addition of the photonic crystal cavity increases the photocurrent, conversion efficiency, and the signal to noise ratio(More)
The group velocity of light becomes superluminal in a medium with a tuned negative dispersion, using two gain peaks, for example. Inside a laser, however, the gain is constant, equaling the loss. We show here that the effective dispersion experienced by the lasing frequency is still sensitive to the spectral profile of the unsaturated gain. In particular, a(More)
When matter is cooled from high temperatures, collective instabilities develop among its constituent particles that lead to new kinds of order. An anomaly in the specific heat is a classic signature of this phenomenon. Usually the associated order is easily identified, but sometimes its nature remains elusive. The heavy fermion metal URu(2)Si(2) is one such(More)
We present the design and implementation of a phase luminometry sensor system with improved and tunable detection sensitivity achieved using a complementary metal-oxide semiconductor (CMOS) integrated circuit. We use sol-gel derived xerogel thin films as an immobilization media to house oxygen (O2) responsive luminescent molecules. The sensor operates on(More)
The rapid increase in the motorization and urbanization to meet the needs of the people has resulted in increasing the number of vehicles in Indian roads during the past few years. With the great ease to public it has also resulted in degrading the environment to the greatest possible extents [5]. Besides gaining control over the air water and land now a(More)
We report a new demonstration of nanoscale solution-processed photodetectors by fabricating a nano-sized gap between two electrodes and drop-casting nanocrystal quantum dots (NCQDs) into the gap. We demonstrate a detection sensitivity of 62 pW with a max responsivity of 2.7 mA/W over a device with a nano-gap of 25 nm. Additionally, we characterize the(More)
Motivated by experiment, we review the case for phase inhomogeneity in U Ru 2 Si 2. In this scenario, the paramagnetic hidden order phase coexists with small distinct domains of antiferromagnetism whose volume fraction increases with pressure. The implications for the nature of the hidden order are discussed. 1 The heavy fermion material URu 2 Si 2 poses a(More)
—In this paper we present a semantic web framework that can be used to generate web-based, e-learning and e-assessment environments for any given knowledge domain. We accomplish this by generating " learning ontolo-gies " for a given knowledge domain. The generated learning ontologies are built upon our previous work on domain " Glossary " ontology and(More)
  • D F Agterberg, M J W Dodgson, H Akiyama, L N Pfieffer, M Yoshita, A Pinczuk +38 others
  • 2004
Comment on 'London theory for superconducting phase transitions in external magnetic fields: Application to UPt 3 ' – Reply " Phys. Coulomb-correlated electron-hole plasma and gain in a quantum-wire laser of high uniformity " Phys. Rev. B 67, 0413021-4 (2003). O. AL-MUSHADANI and R.J. NEEDS " Free energy calculations of intrinsic point defects in silicon "(More)
When matter is cooled from high temperatures, collective instabilities develop amongst its constituent particles that lead to new kinds of order. 1 An anomaly in the specific heat is a classic signature of this phenomenon. Usually the associated order is easily identified, but sometimes its nature remains elusive. The heavy fermion metal URu 2 Si 2 is one(More)
  • 1