An official website of the United States government
Subramania, Ganapathi S; Foteinopoulou, Stavroula
(Ed.)
Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher.
Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?
Some links on this page may take you to non-federal websites. Their policies may differ from this site.
-
-
Subramania, Ganapathi S.; Foteinopoulou, Stavroula (Ed.)
-
Subramania, Ganapathi S.; Foteinopoulou, Stavroula (Ed.)
-
Subramania, Ganapathi S.; Foteinopoulou, Stavroula (Ed.)
-
Subramania, Ganapathi S.; Foteinopoulou, Stavroula (Ed.)We will discuss two kinds of exceptional points of degeneracy in waveguides and their respective application in lasers. Such exceptional points occur in waveguides with balanced loss and gain (e.g., PT symmetry), and in waveguides without loss and gain (e.g., periodic Si waveguides). Waveguides with such exceptional points have a strong degeneracy of their wavenumbers and polarization states that enables specific wave physics, only found in these degenerate systems. We will discuss advantages and disadvantages of both concepts to conceive laser regimes, related to high power, high spectral purity, high efficiency, etc, and show some realistic designs involving Si ridge waveguides.more » « less
-
Subramania, Ganapathi S.; Foteinopoulou, Stavroula (Ed.)We model the e ect of concentrated sunlight on CIGS thin- lm graded-bandgap solar cells using an optoelectronic numerical model. For this purpose it is necessary first to solve the time-harmonic Maxwell equations to compute the electric eld in the device due to sunlight and so obtain the electron-hole-pair generation rate. The generation rate is then used as input to a drift-diffusion model governing the flow of electrons and holes in the semiconductor components that predicts the current generated. The optical submodel is linear; however, the electrical submodel is nonlinear. Because the Shockley{Read{Hall contribution to the electron-hole recombination rate increases almost linearly at high electron/hole densities, the effciency of the solar cell can improve with sunlight concentration. This is illustrated via a numerical study.more » « less
-
Subramania, Ganapathi S.; Foteinopoulou, Stavroula (Ed.)
-
Subramania, Ganapathi S.; Foteinopoulou, Stavroula (Ed.)
-
Subramania, Ganapathi S.; Foteinopoulou, Stavroula (Ed.)Data usage across the internet is growing exponentially, fueled primarily by the move to cloud computing and penetration of streaming services into developing countries. To address the growing energy needs of data centers, we propose an all oxide plasmon assisted electro-optic modulator, which features enhanced light-matter interaction, and compact sizes as seen in plasmonic modulators while at the same time maintaining low insertion losses, as seen in photonic modulators. This is achieved by utilizing a device design that selectively engages and disengages the lossy plasmonic component, as the device switches from low transmission to high transmission modes.more » « less
-
Subramania, Ganapathi S.; Foteinopoulou, Stavroula (Ed.)
