Analysis of double-parallel amplified recirculating optical-delay lines

A novel method of analysis of double-parallel amplified recirculating optical-delay lines (DPAROD) is presented. The location of the maxima and the minima of the transfer function for this configuration is calculated and experimentally demonstrated. The influence of different parameters, such as the coupling coefficients, gains, lengths of the fiber loops and fractional losses of the directional couplers, on the shape of the transfer function are analyzed. Different measurements have been taken to verify this model. The potential application of these interconnected delay loops as filters is a reason for developing this method.Publicad

Light Engineering of the Polariton Landscape in Semiconductor Microcavities

We demonstrate a method to create potential barriers with polarized light beams for polaritons in semiconductor microcavities. The form of the barriers is engineered via the real space shape of a focalised beam on the sample. Their height can be determined by the visibility of the scattering waves generated in a polariton fluid interacting with them. This technique opens up the way to the creation of dynamical potentials and defects of any shape in semiconductor microcavities.Comment: 4 pages, 5 figure

Amplified Fiber-Optic Recirculating Delay Lines

Experimental and theoretical results on single- and double-amplified recirculating delay lines are presented. One of our aims is to emphasize their application as filters, showing a wide flexibility of design. Analysis of their performance in the spectral and time domains have been carried out. A novel method of understanding the behavior of double structures has been developed and successfully tested with experimental results employing Er-doped fiber amplifiers as delay lines.Publicad

Dynamics of formation and decay of coherence in a polariton condensate

We study the dynamics of formation and decay of a condensate of microcavity polaritons. We investigate the relationship between the number of particles, the emission's linewidth and its degree of linear polarization which serves as the order parameter. Tracking the condensate's formation, we show that, even when interactions are negligible, coherence is not determined only by occupation of the ground state. As a result of the competition between the coherent and thermal fractions of the condensate, the highest coherence is obtained some time after the particle number has reached its maximum

Spectral Fuzzy Classification: A Supervised Approach.

The goal of this paper is to present an algorithm for pattern recognition,leveraging on an existing fuzzy clustering algorithm developed by Del Amo et al. [3, 5], and modifying it to its supervised version, in order to apply the algorithm to different pattern recognition applications in Remote Sensing.The main goal is to recognize the object and stop the search depending on the precision of the application. The referred algorithm was the core of a classification system based on Fuzzy Sets Theory (see [14]), approaching remotely sensed classification problems as multicriteria decision making problems, solved by means of an outranking methodology (see [12] and also [11]). The referred algorithm was a unsupervised classification algorithm, but now in this paper will present a modification of the original algorithm into a supervised version

Aspects of the biology of Ephestia cautella and Tribolium castaneum on fermented stored cocoa beans

 Ephestia cautella (Walker) (Lepidotera: Pyralidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) are pests associated with dried fermented stored cocoa beans that cause extensive damage. The biology of these pests on cocoa beans in Ghana has not been well documented, especially on T. castaneum. Due to climate changes and improved/hybrid seedlings being released to farmers, it has become necessary to re-evaluate the biology and damage of these pests on fermented stored cocoa beans. The experiments were conducted in the Insectary laboratory of the Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. Paired 0-1 day old E. cautella adults were placed in Petri dishes and covered with Kilner jars. The eggs laid daily by each female were carefully transferred onto 15 g cocoa beans in Petri dishes. The egg incubation period was four days, 31 days larval period and the pupal period of seven days. Unmated adult males lived for 12.1 days and females 7.9; mated males lived for 10.9 days and females 5.5. Paired T. castaneum were introduced on 2.0 g broken cocoa beans in Petri dishes. The average incubation period was nine days, 40 days larval period, and pupal period of five days