An AlGaAs waveguide array below the half-bandgap is used to investigate experimentally basic dynamic features of discrete systems. In particular, nonlinear locking of a discrete soliton to its input waveguide was observed for certain input conditions. We also investigated the soliton dynamics as a function of the position of the initial excitation and found that small shifts from the centers of symmetries of the structure could be greatly enhanced. Both effects depend on the geometry of the array and on the beam size.
Augmented low index waveguides consist of a dual core waveguide layer where the transverse electric (TE) mode is confined to the high index region and the transverse magnetic (TM) mode is confined to the lower index core. The result is a large difference in propagation constants between the TE and TM modes which has applications for on-chip polarization manipulation. In this paper we will demonstrate how this concept can be used to realize polarization rotation, polarization beam splitters and polarizers in the silicon photonics platform.
We suggest and implement a method for observing Manakov spatial solitons in crystals. We show experimentally that the propagation behavior of mutually trapped, orthogonally polarized beams in AlGaAs planar waveguides is identical to that of a fundamental (single polarization) soliton beam with the same total power.
We report an experimental study of discrete gap solitons in binary arrays of optical waveguides. We observe self-focusing indicating soliton generation when the inclination angle of an input beam is slightly above the Bragg angle and show that the propagation direction of the emerging gap soliton is influenced by the effect of interband momentum exchange.
Accounting for material absorption is very important for developing high quality factor (Q) photonic crystal cavities. However, to our knowledge, there have been very few systematic experimental investigations of its role in such cavities. In this paper, we present detailed experiments to reveal the relationship between Q, material absorption coefficient and field pattern. Modes with different field patterns and materials with different absorption coefficients were tested. We have developed a simple formula to describe the relationship, which can be used to replace time-consuming numerical calculations. The experimental and numerical data agree well with this formula.
There is a growing need for diagnostic technologies which can provide accurate disease detection using sensitive, reliable, and inexpensive methods. A lot of research has been directed towards developing efficient point-of-care devices that enable the parallel detection of multiple analytes, in small-volume samples, with high sensitivity and in a short time. Flow cytometry, used for bead-based immunoassays are expensive and bulky. Using a microfluidic based optical detection system makes the whole process convenient and cheap. This motivates us to explore this platform for multiplexed testing by incorporating microbead-based assays. Hence, we aim to develop a microfluidics based optical detection system, which can measure multiple analytes at the same time for diseases like dengue. Dengue detection using NS1-4 (non-structural protein), which inflates on the first day of virus with the IgG antibody, can give significant information for the treatment. Simultaneous detection of dengue antigen and antibody is crucial for prevention and diagnosis of dengue infection. The outcome of this study generates the first-generation prototype of a universal fluorescence detection device capable of both classifying the microspheres and measuring the amount of specific biomarker.
We consider the interaction within a bunch of two coherent optical pulses in a one dimensional, resonant photonic crystal which includes a defect produced by a coherent pump. Using numerical methods, the defect is shown to provide a selective reversible trap for a gap soliton mediated by the long-range coupling. This opens up new opportunities for signal transmission control and light localization.
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