Quantum dots (QDs) are highly stable, spectrally well-defined, and engineerable quantum emitters. Their emission energy can be tuned by the growth parameters. QDs can be used for a variety of light sources (classical light source and quantum emitter), such as light emitting diodes, lasers, and single- and entangled-photon sources. Single QD also acts as a single photon source which can be used as a flying qubit source in quantum devices. 

Due to the spherically symmetric emission profile from a single QD, a significant amount of emission intensity from the dots are not collected in QDs based photonic devices. This limits the use of QDs as an active light source. Secondly, most of quantum and classical light sources demand bright photon sources with control over polarization, positioning of these quantum emitters as well switchability of the emission. Therefore, there is need to design such QDs based light sources which have intense, directed, polarization-controlled and switchable emission. 

Towards this goal, we plan to fabricate quantum dots based efficient and controllable light sources using two different routes: (1) Dielectric nanoantenna, and (2) Liquid crystal (LC) based switchable light sources. For this purpose, we synthesized CdSe\CdS core\shell quantum dots by using high temperature chemical bottom-up technique and have natural emission at 627nm. In the next step, we plan to fabricate QDs based planar dielectric nanoantenna and investigate the enhanced, directional, and polarization dependent emission from them. We are especially interested in probing the effects of nearby interfaces in such devices on charge fluctuations and on the emission properties of the quantum dots. For the second class of devices, we first plan to synthesize liquid crystal-quantum dots composites and study their optoelectronic properties. The composite will then be used to realize hybrid QDs-liquid crystal devices. We aim to explore distribution and self-organization of QDs in such devices and the effect of electric field on QD distribution as well as emission. The aim is to realize patterned switchable QD based light crystal light sources. Such sources with low dot density can be used as switchable quantum light sources. This comprehensive experimental work on QDs based efficient light sources can find potential applications in quantum technology, lasing and photonic based communication systems. 

Proposal Defence Committee

• Dr Ata Ulhaq (Supervisor)
• Dr. Nauman Zafar Butt
• Dr Ammar Ahmed Khan

Join via Zoom here.

Meeting ID: 929 9106 9088
Passcode: 006879

Grand Unified Theories (GUTs) provide a compelling framework for unifying the strong, weak and electromagnetic interactions. Combining GUTs with Einstein’s general relativity yields a versatile arena for investigating a variety of fundamental questions including the physics of the very early universe, origin of large scale structure in the universe, creation of “matter” in the universe, nature of “dark” matter, isotropy of the observed cosmic microwave background, and many others. 

Zoom Online Meeting ID: 999 6075 4758

Passcode: 786154

The physical systems described by nonlinear partial differential equations with exact analytical solutions are generally known as integrable systems. They are also very important from the physics point of view, as these equations occur in many different disciplines of physics like nonlinear optics, hydrodynamics, theory of condensed matter, plasma physics etc. Such systems are very rare only handful of equations are there. Most nonlinear differential equations admit chaotic behavior and no explicit solutions can be written down. There are number of techniques to find exact solutions.

Zoom Online Meeting ID: 999 6075 4758

Passcode: 786154

 

Density Functional Theory (DFT) is the most popular method for the quantum mechanical study of matter. The existing local/semi local DFT functionals fail to describe long-range electron-electron correlation interactions. These long-range electron-electron correlation interactions are also known as dispersion interactions. To overcome this deficiency of DFT several correction methods have been designed. These methods add dispersion energies to the interaction energies computed using DFT, thus called DFT+D methods. DFT+D methods taper off the dispersion energies at distances near the van der Waals minima and smaller presuming that DFT begins to reproduce the dispersion energies at such distances. We will discuss the extent to which this assumption is true. A new non-empirical method for the inclusion of nonlocal correlation effects in DFT will be discussed as well.

Zoom Online Meeting ID: 999 6075 4758

Passcode: 786154

Realization of robust, scalable, and controllable qubit which can be integrated into a quantum circuit is one of the most sought-after goal of current quantum technology research. In this Colloquium, the speaker will discuss the physics and device aspects of spin qubits realized using semiconductor quantum dots.

In this talk, I will talk about a special kind of diffuse imaging geometry which involves using a rough relay surface to image objects which are hidden around corners. Precise photon timing information as well as a knowledge of laser positions and the camera positions on the relay surface enable traditional non-line-of-sight (NLoS) reconstruction algorithms to reconstruct the hidden scene using multi-bounce scattered photons that eventually make it back to the detector. I will also talk about some of the potential future work in the area of wave-based diffuse imaging.

Zoom Online Meeting ID: 999 6075 4758

Passcode: 786154

Get ready for the most exciting fusion of biology and physics; the LUMS International BioPhysics Workshops! Register for free! 

In its second chapter, the virtual workshop will highlight the revolution in the study of Macromolecular Structure & Dynamics led by developments in:

• High-flux synchrotron beamlines
• Optical physics of micro-crystallites
• Cryogenic electron microscopy (Cryo-EM)
• High-performance computing.

The workshop series introduce cutting edge developments in the study of complex Biological and Organic materials. Their links to the core principles of Physics, Information Science, Molecular Biology and Organic Chemistry will be emphasized. It aims to build a BioPhysics research community within Pakistan in addition to collaborations with regional and international partners. Dedicated round table sessions will involve discussions about how the multidisciplinary culture required to nurture this area can be created.

This workshop will draw together national and international speakers/researchers working at the interfacial disciplines of Structural Biology, Molecular Dynamics and Materials Physics.

Keynote Speaker:

Prof. Jose Carazo, National Center for Biotechnology (Spain) Keynote “Cryo-EM – It’s amazing capability to follow macromolecular structural changes”

Featured Speakers:

Dr. Jay Nix , (Lawrence Berkeley Labs, USA)

Drs. Geerten Vuister/Vicky Higman, (Leicester University, USA)

Speakers:

Dr. Tanweer Hussain (Indian Institute of Science, India) Dr. Hamayun Sharif (Harvard University, USA)
Dr. Syed Arif (Blundell Group – Cambridge University, UK) Dr. Anas Khawaja (Karolinska Institut, Sweden)
Dr. Ishrat Jabeen (NUST, Islamabad)
Dr. Hammad Naveed (NUCES-FAST Lahore)
Dr. Shafqat Rasool (McGill University, Canada)
Dr. Arooj Shafiq (Salim Habib University)
Dr. Maqsood Ahmad (Islamia University, Bahawalpur) Dr. Moaz Rahman (Punjab University, Lahore)
Dr. Javed Akhtar (PINSTECH, Islamabad)
Dr. Shahid Khan (Lawrence Berkeley Labs, USA)
Dr. Shahzad ul Hassan (SBASSE, LUMS, Lahore) (Leicester University, USA)

For more information: visit this webpage.
Or
Contact:
Ata Ulhaq , ata.haq@lums.edu.pk

Shahzad Ul Hassan , shahzad.hussan@lums.edu.pk

Muhammad Arshad Maral , arshad.maral@lums.edu.pk

Registration deadline: Sunday, March 20, 2022.