Prof. Tal Carmon. 

Faculty of Mechanical Engineering, Technion -, Haifa, Israel

Wednesday, February 15th  , 2017

13:00-14:00

Light refreshments and drinks will be served starting 12:30

Auditorium 011, Engineering Class Room Building,

Faculty of Engineering, Tel-Aviv University

Abstract:

We fabricate a new type of optofluidic micro-device with walls made strictly of water. Our water-walled devices can therefore co-host water waves and light waves and enable energy exchange between electromagnetic and capillary resonances. 

Activation our opto-capillary cavity, while tuned to its non-resolved sideband, we experimentally demonstrate enhancement of the redder (Stokes) scattering of light from water waves; which allows excitation of water wave laser. This laser is similar to Brillouin lasers; but it relies on water waves instead of sound. 

Going to the opposite sideband enables ripplon annihilation and (anti-Stokes) optical cooling of water waves.

In addition to extending Raman-lasers and -coolers to rely also on water waves, transforming solid walls to interfaces made of the liquid phase of matter makes water-walled devices a million times softer than what current solid-based technology allows. This softness implies a giant optical controllability and coolability that might, one day, allow optically cooling such devices toward their quantum ground state from room temperature.

You are invited to attend a lecture

New Frontiers in Band-Gap Engineering: Stretching the Limits of Quantum Transport

By:

Dr. Asaf Albo

Research Laboratory of Electronics, Massachusetts Institute of Technology, USA

Abstract

The extreme precision in semiconductor materials growth together with their high quality allows to extend band-gap engineering to control not only the band gap across a device but also the electron dynamics and scattering processes. One of the greatest achievements using this approach is terahertz  quantum cascade lasers (THz-QCLs) founded on designed electron dynamics in less than handful of subbands. As a demonstrative case study for this capability, I will review my efforts to untangle the complexity of the temperature driven electron transport in THz-QCLs towards extending their operation to room temperature (). This study has led to the experimental demonstration of negative differential resistance at room temperature in THz-QCL structures. This is a strong evidence for the possibility to achieve lasing at room temperature.  The study points also to a future direction in quantum engineering that is to control and manipulate generated heat and carriers’ temperature for the benefit of the device and for the realization of novel device concepts.

A further example of novel band gap engineering is the expansion in design flexibility of devices through the synthesis of novel semiconductor materials.  The incorporation of additive atoms to conventional semiconductor alloys is suggested as an efficient strategy to extend their functionality. As an example for this approach, I will review my contributions on MOCVD growth of mixed-anion III-V-N (dilute-nitrides) alloys and demonstrate the increased flexibility that was achieved in designing novel quantum structures and devices.

I will conclude with presenting the high potential of related novel III-nitride (III-N) materials and quantum structures to solve key technological challenges in optoelectronics.

On Thursday, January 26, 2017, 15:00

Room 011, Kitot building