EE Student Information

Optics and Electronics Seminar

Applied Physics 483 Optics & Electronics Seminar: Meta-optics: From Flat Lenses to Structured Light and Dark

Topic: 
Meta-optics: From Flat Lenses to Structured Light and Dark
Abstract / Description: 

Subwavelength spaced arrays of nanostructures, known as metasurfaces, provide a new basis for recasting optical components into thin planar elements, easy to optically align and control aberrations, leading to a major reduction in system complexity and footprint as well as the introduction of new optical functions. The planarity of flat optics will lead to the unification of semiconductor manufacturing and lens making, where the planar technology to manufacture computer chips will be adapted to make CMOS compatible metasurface based optical components for high volume markets like cell phones. New polarization sensitive and depth cameras will be discussed. Metasurfaces also offer fresh opportunities for structuring light as well as dark. I will discuss spin to total orbital angular momentum (OAM) converters and high OAM lasing, as well as flat devices that enable light’s spin and OAM to evolve, simultaneously, from one state to another along the propagation direction. Finally, the demonstration of 2D phase and polarization singularities and the unique applications that they will open up will be discussed

Date and Time: 
Monday, October 11, 2021 - 4:15pm

Applied Physics 483 Optics & Electronics Seminar: Extreme wave phenomena enabled by broken symmetries

Topic: 
Extreme wave phenomena enabled by broken symmetries
Abstract / Description: 

In this talk, I discuss the role of symmetry breaking in nano-optics, photonics, electromagnetics and acoustics, to tailor and engineer wave phenomena. I will overview a range of low-symmetry natural and artificial materials whose interactions with light and sound are tailored and enhanced through geometrical and/or temporal symmetry breaking. Special opportunities arise when considering systems in which light and matter are strongly coupled, as in the case of polaritonics, for which extreme linear and nonlinear responses are unveiled by controlling the underlying symmetries. I will also discuss the role of symmetry breaking to induce nonreciprocal and topological wave phenomena and the various opportunities they enable for photonic technologies.

Date and Time: 
Monday, October 4, 2021 - 12:00pm

SPRC & SOS Seminar: Trace Gas Flux Measurements in Artic Ecosystems – Current Applications and Future Perspectives

Topic: 
Trace Gas Flux Measurements in Artic Ecosystems – Current Applications and Future Perspectives
Abstract / Description: 

The exchanges of carbon dioxide (CO2) and methane (CH4) between arctic ecosystems and the atmosphere are sizeable and may if they change may alter the further development of climate warming. These fluxes take place between the atmospheric background of these trace gases and a very large reservoir of organic carbon stored in arctic soils and sediments. The stored carbon amounts to more than twice the current global atmospheric burden of CO2. Therefore, accurate measurements of the fluxes and how they vary temporally and spatially is key to understanding possible ecosystem impacts on the atmospheric mixing ratios and hence climate.
This presentation will detail the current state of the global CO2 and CH4 budget and review methods applied in quantifying the arctic trace gas flux components. The presentation will show new developments in the attempts to use UAV's to help improve spatial coverage of measured fluxes. The challenges in applying the laser techniques needed for the precise and fast trace gas measurements under true arctic conditions will be discussed.

Date and Time: 
Tuesday, May 4, 2021 - 11:00am to Wednesday, May 5, 2021 - 10:55am

Optics & Electronics seminar: Inverse Designed Integrated Photonics

Topic: 
[AP483] Inverse Designed Integrated Photonics
Abstract / Description: 

Photonics with superior properties can be implemented in a variety of old (silicon, silicon nitride) and new (silicon carbide, diamond) photonic materials by combining state-of-the- art photonics optimization techniques (photonics inverse design) with new fabrication approaches. In addition to making photonics more robust (e.g., to errors in fabrication and variation in temperature), more compact, and more efficient, this approach can also enable new functionalities. While in our early work we focused on inverse design and demonstration of individual photonic devices, our more recent work focused on scaling it to photonic integrated circuits fabricated in a commercial semiconductor foundry. We illustrate this with several examples, including optical interconnects based on a combination of mode and wavelength division multiplexing, and photonic chips for optical beam steering.


 

Spring 2021 speakers organized by Prof. David A.B. Miller

Date and Time: 
Monday, May 24, 2021 - 4:15pm

Optics & Electronics seminar: Energy Efficient, Multi-Terabit Photonic Connectivity for Disaggregated Computing

Topic: 
[AP483] Energy Efficient, Multi-Terabit Photonic Connectivity for Disaggregated Computing
Abstract / Description: 

High performance data centers are increasingly bottlenecked by the energy and communications costs of interconnection networks. Integrated silicon photonics with dense wavelength-division multiplexing offer the opportunity of optical connectivity that directly delivers high off-chip communication bandwidth densities with low power consumption. We introduce the concept of embedded photonics for deeply disaggregated architectures. Beyond alleviating the bandwidth/energy bottlenecks, the new architectural approach enables flexible connectivity tailored for specific applications.


 

Spring 2021 speakers organized by Prof. David A.B. Miller

Date and Time: 
Monday, May 3, 2021 - 4:15pm

Optics & Electronics seminar: End to End Optimization of Optics and Algorithms

Topic: 
[AP483] End to End Optimization of Optics and Algorithms
Abstract / Description: 

Neural networks and other advanced image processing algorithms excel in a wide variety of computer vision and imaging applications, but their high performance also comes at a high computational cost, and their success is sometimes limited. In this talk, we explore hybrid optical-digital strategies to computational imaging that outsource parts of the algorithm into the optical domain. Using such a co-design of optics and image processing, we can design application-domain-specific cameras or compute parts of a convolutional neural network in optics. Optical computing happens at the speed of light and without any memory or power requirements, thereby opening new directions for intelligent imaging systems.


 

Spring 2021 speakers organized by Prof. David A.B. Miller

Date and Time: 
Monday, April 26, 2021 - 4:15pm

Optics & Electronics seminar: Playing Hide-and-Seek at the Nanoscale – Tailored Field Landscapes for Precise Particle Tracking and More

Topic: 
[AP483] Playing Hide-and-Seek at the Nanoscale – Tailored Field Landscapes for Precise Particle Tracking and More
Abstract / Description: 

Intensity, phase, and polarization of electromagnetic fields can be tailored to form bespoke distributions. This spatial structure of light is an intriguing playground. It finds a wide range of applications in optical communications, sensing, imaging, and beyond. However, the real beauty of structured fields comes to light when considering strongly confined electromagnetic fields, which naturally feature complex three-dimensional distributions. These engineered light fields can be utilized, for example, to selectively excite individual nanosystems, extending the range of possible applications even further by enabling advanced single-particle spectroscopy, nanoscale traffic control, nano-metrology, and more.

In this talk, we introduce a novel scheme for ultra-precise particle localization and tracking, which is based on the interaction of structured light and individual nanoparticles. We show that by utilizing the strongly position-dependent scattering pattern as a ruler, we can retrieve the exact particle position from the far-field scattering signal. Besides the fundamental ingredients and recipe of this technique, we also highlight selected next steps and future plans. For instance, we also discuss the fundamental idea behind next generation camera technology to boost the capabilities of our nanometrology schemes. These novel pixels and cameras based on light-processing circuitry are jointly developed, together with other European and international experts, as part of the 'SuperPixels' project (https://www.superpixels.org/). They will allow for a simultaneous measurement of polarization and phase distributions in addition to light's intensity.

[This project has received partial funding from the European Commission Horizon 2020 research and innovation program under the Future and Emerging Technologies Open Grant Agreement Super-Pixels No. 829116]


 

Spring 2021 speakers organized by Prof. David A.B. Miller

Date and Time: 
Monday, April 19, 2021 - 12:00pm to Tuesday, April 20, 2021 - 11:55am

Optics & Electronics seminar: Semiconductor Nanocrystal Optoelectronics: A Journey from Colloidal Quantum Dots to Wells

Topic: 
[AP483] Semiconductor Nanocrystal Optoelectronics: A Journey from Colloidal Quantum Dots to Wells
Abstract / Description: 

Semiconductor nanocrystals have attracted great interest for color conversion and enrichment in quality lighting and displays. Optical properties of these solution‑processed nanostructures are conveniently controlled by tailoring their size, shape, and composition in an effort to realize high‑performance light generation and lasing. These colloids span different types and heterostructures of semiconductors in the forms of quantum dots and rods to the latest sub‑family of nanocrystals, the colloidal quantum wells (CQWs). In this talk, we will introduce the emerging field of semiconductor nanocrystal optoelectronics, with most recent examples of their photonic structures and optoelectronic devices employing such atomically‑flat, tightly‑confined, quasi‑two‑dimensional CQWs, also popularly nick-named 'nanoplatelets'. Among their various extraordinary features, we will show that these CQWs enable record high optical gain coefficients [1] and can achieve gain thresholds at the level of sub‑single exciton population per CQW on average [2], empowered by carefully engineering their heterostructure [3]. Next, we will present a new, powerful, large-area self‑assembly tool for orientation controlling of these nanoplatelets [4], which provides us with the ability to tune and master their excitonic properties in their ensemble, as well as the level of achievable energy transfer among them and with other nearby species. Using three‑dimensional constructs of face‑down self‑assembled slabs of CQWs with monolayer precision, we will demonstrate ultrathin optical gain media and lasers of these oriented CQW assemblies [5]. Finally, we will show record high‑efficiency colloidal LEDs using CQWs employed as the electrically‑driven active emitter layer [6] and record low-threshold solution lasers using the same CQWs employed as the optically‑pumped fluidic gain medium [7]. Given their current accelerating progress, these solution‑processed quantum well materials hold great promise to challenge their epitaxial thin‑film counterparts in semiconductor optoelectronics in the near future.

[1] B. Guzelturk et al., HVD, Nano Letters 19, 277 (2019)
[2] N. Taghipour et al., HVD, Nature Comm 11, 3305 (2020)
[3] Y. Altıntas et al., HVD, ACS Nano 13, 10662 (2019)
[4] O. Erdem et al., HVD, Nano Letters 19, 4297 (2019)
[5] O. Erdem et al., HVD, Nano Letters 20, 6459 (2020)
[6] B. Liu et al., HVD, Advanced Materials 32, 1905824 (2020)
[7] J. Maskoun et al., HVD, Advanced Materials (2021), in print, DOI:(10.1002/adma.202007131)


Spring 2021 speakers organized by Prof. David A.B. Miller

Date and Time: 
Monday, April 12, 2021 - 12:00pm to Tuesday, April 13, 2021 - 11:55am

Optics & Electronics seminar: Creation of Time Reversed Optical Waves

Topic: 
[AP483] Creation of Time Reversed Optical Waves
Abstract / Description: 

In this talk, a new type of beam shaper will be discussed, capable of generating arbitrary vector spatiotemporal beams, where the user can define the amplitude, phase, and polarization independently for each point in space and time. This beam shaper was recently used to demonstrate time reversed optical waves. Such waves propagate through complex media, as if watching a traditional scattering process in reverse - starting as a complicated ‘pre-scattered’ wave, which then becomes a desired target field at the distal end of the complex media.


Spring 2021 speakers organized by Prof. David A.B. Miller

 

Date and Time: 
Monday, April 5, 2021 - 4:15pm

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