Ivan Avrutsky

 

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Integrated Optics
Surface Plasmons
2D Wavegude Gratings
Lasers and Quantum Wells
Lasers Annealing and Ablation
Waveguide Gratings

 

Welcome to the Integrated Optics and Nanophotonics Laboratory!

 

The key words hitting the hart of what we are doing are guided modes on gratings, optics of nanostructured materials, and sub-diffraction features in laser annealing and ablation.

 

We design, fabricate, test, and simulate optoelectronic devices employing waveguide gratings and nanostructured materials. We study physics of light interaction with such objects. Practical applications are mostly in the areas of optical communication and optical sensors.

 

Gratings provide phase matching of waves with different wavevectors and thus facilitate interactions that would be impossible or extremely inefficient in a uniform medium. Examples include coupling between free-space beams and guided modes, in-plane Bragg resonances turning a waveguide grating into a 1D or 2D photonic crystal, wavelength selection in optoelectronic devices such as semiconductor lasers or fiber filters using Bragg gratings, grating assisted harmonic generation and parametric conversion in nonlinear materials, fine-tune of the quantum selection rules in generation of entangled photons, and many others.

 

Light confinement and guiding in most of cases is achieved in transparent dielectrics and relies on the total internal reflection, the Bragg reflection in photonic crystal waveguides,  strong reflection from a metallic surface in microwave-style pipe waveguides, or on the collective excitation of the electromagnetic field and plasma of free electrons in metals in case of surface plasmons.

 

Nanostructuring offers a tool to tailor the optical properties of materials. Bragg gratings and photonic crystals are considered by many as nanostructured materials as long as they may have deep submicron features, often below 100nm. But truly nanoscale phenomena reside at much smaller length scale. Energy levels for electrons and holes, and thus the optical properties of semiconductor quantum  wells/wires/dots are determined, in part, by geometry and dimensions of the structure, typically at or below 10nm. Also, light penetration into metals is often measured by a few dozens of nanometers only. Light interaction with nano-scale metallic objects is a subject of nano-plasmonics.

 

While in a laser annealing/ablation experiment the free-space laser beam obeys the diffraction limit for focusing, the processed material may reveal sub-diffraction features, in some cases approaching the nanoscale. In a sense, light only initiates complex thermo- and hydro-dynamic processes that shape the melted material. Tiny holes or nano-sharp conical spikes can be manufactured at precisely pre-determined locations on silicon-on-insulator thin films with appropriately chosen physical parameters. These nano-structures can also be used in optoelectronic devices.

 

If you are looking for expertise in nanoscale photonics, plasmonics, guided wave optics, or optical gratings, you are at the right place. Take a look at our current projects, recent publications, areas of expertise, fabrication and characterization facility. We will be glad to work with you.

 

Ivan Avrutsky