EE Student Information

The Department of Electrical Engineering supports Black Lives Matter. Read more.

• • • • •

EE Student Information, Spring Quarter through Academic Year 2020-2021: FAQs and Updated EE Course List.

Updates will be posted on this page, as well as emailed to the EE student mail list.

Please see Stanford University Health Alerts for course and travel updates.

As always, use your best judgement and consider your own and others' well-being at all times.

Applied Physics / Physics Colloquium

Applied Physics/Physics Colloquium presents "Twisty fun in 2D materials"

Topic: 
Twisty fun in 2D materials
Abstract / Description: 

A van der Waals bonded solid consists of sheets of two-dimensional (2D) atomic layers with strong bonding in-plane. When these crystals are grown naturally, the stacking order along the out-of-plane dimension is dictated by the van der Waals force, typically leading to all layers of the crystal being oriented in the same in-plane direction. Recently, it has become possible to synthetically create materials where the individual layers have arbitrary in-plane direction relative to each other. These materials are of great interest theoretically since they realize new crystal structures not achievable in nature, with new emergent properties predicted. One of the key experimental findings in one such material last year was the presence of superconductivity and Mott insulating behavior in twisted bilayer graphene, properties that the individual layers do not display by themselves. In this talk, I will describe STM and transport properties of three such materials: (a) twisted bilayer graphene, where we measure the electronic structure of the material that is a Mott insulator (b) twisted bilayer WSe2, where we also observe Mott insulating behavior and (c) twisted double bilayer graphene, where we have evidence from STM for excitonic insulator behavior as well as the presence of chiral topological edge states in the interior of the material.


Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, January 28, 2020 - 4:30pm
Venue: 
Hewlett 200

Applied Physics/Physics Colloquium presents "Space Observatories of the Highest Energy Particles: POEMMA & EUSO-SPB"

Topic: 
Space Observatories of the Highest Energy Particles: POEMMA & EUSO-SPB
Abstract / Description: 

What are the mysterious sources of the most energetic particles ever observed? What are the sources of energetic cosmic neutrinos? How do particles interact at extreme energies?


Building on the progress achieved by the ground-based Auger Observatory in studying cosmic particles that reach 100 EeV, an international collaboration is working on space and sub-orbital missions to answer these questions. The Extreme Universe Space Observatory (EUSO) on a super pressure balloon (SPB) is designed to detect ultra-high energy cosmic rays (UHECRs) from above. EUSO-SPB1 flew in 2017 with a fluorescence telescope. EUSO-SPB2 is being built to observe both fluorescence and Cherenkov from UHECRs and neutrinos. These sub-orbital missions lead to POEMMA, the Probe Of Extreme Multi-Messenger Astrophysics, a space mission designed to discover the sources of UHECRs and to observe neutrinos above 20 PeV from energetic transient events. POEMMA will open new Multi-Messenger windows onto the most energetic events in the Universe, enabling the study of new astrophysics and particle physics at these otherwise inaccessible energies


Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, January 21, 2020 - 4:30pm
Venue: 
Hewlett 200

Applied Physics/Physics Colloquium presents "Quantum oscillations in solids: past, present and future"

Topic: 
Quantum oscillations in solids: past, present and future
Abstract / Description: 

On a visit to Stanford to honor Ted Geballe's centennial, I think it is appropriate to talk about an aspect of condensed matter and materials physics that has spanned his entire professional lifetime. The de Haas – van Alphen effect is one of the most profound and pronounced manifestations of quantum mechanics in solids. Discovered in Leiden fully ninety years ago as a signal in the magnetic torque of bismuth, the effect is now observed in a huge range of physical properties, and often given the general name of 'quantum oscillations'. The quest from discovery to full understanding required seminal contributions from some of the most celebrated names of twentieth century physics, such as Landau, Onsager and Lifshitz. The true hero of the technique, perhaps less well known than the above friends and colleagues with whom he collaborated, was the Cambridge-based Russian experimental physicist David Shoenberg. I had the privilege of knowing David for the last ten years of his life, and of learning about quantum oscillations from him and from his protégé Gil Lonzarich. In this talk I will review the historical development of the field, and try to show how important it has been, as a driver for the development of low temperature-low noise experimental techniques, for the growth of high purity single crystals, and for the introduction of key concepts in the theory of solids. I will close by stressing that the party is far from over. New physics associated with the de Haas – van Alphen effect still at the forefront of condensed matter science to this day, and there is an ongoing search for even more exotic relatives that are predicted to exist in certain special many-body systems.


Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, January 14, 2020 - 4:30pm
Venue: 
Hewlett 200

Applied Physics/Physics Colloquium presents "Quantum Sensing of Quantum Materials"

Topic: 
Quantum Sensing of Quantum Materials
Abstract / Description: 

The magnetic fields generated by spins and currents provide a unique window into the physics of correlated-electron materials and devices. Proposed only a decade ago, magnetometry based on the electron spin of nitrogen-vacancy (NV) defects in diamond is emerging as a platform that is exceptionally suited for probing condensed matter systems: it can be operated from cryogenic temperatures to above room temperature, has a dynamic range spanning from DC to GHz, and allows sensor-sample distances as small as a few nanometers. As such, NV magnetometry provides access to static and dynamic magnetic and electronic phenomena with nanoscale spatial resolution. While pioneering work focused on proof-of-principle demonstrations of its nanoscale imaging resolution and magnetic field sensitivity, now experiments are starting to probe the correlated-electron physics of magnets and superconductors and to explore the current distributions in low-dimensional materials. In this talk, I will review some of our recent work that uses NV center magnetometry to image skyrmions in thin magnetic films, measure the spin chemical potential in magnetic insulators, and image hydrodynamic electron flow in graphene.

 


Winter Qtr. Colloq. committee: M. Schleier-Smith (Chair), B. Cabrera, S. Dimopoulos, T. Heinz, S. Kachru & L. Tompkins
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, January 7, 2020 - 4:30pm
Venue: 
Hewlett 200

AP 483 Seminar Series presents "Photovoltaic Restoration of Sight in Retinal Degeneration"

Topic: 
Photovoltaic Restoration of Sight in Retinal Degeneration
Abstract / Description: 

Retinal degenerative diseases lead to blindness due to loss of the “image capturing” photoreceptors, while neurons in the “image-processing” inner retinal layers are relatively well-preserved. Information can be reintroduced into the visual system by photovoltaic subretinal implants, which convert incident light into electric current and stimulate the secondary retinal neurons.

 

To provide sufficient light intensity for photovoltaic stimulation while avoiding visual perception by remaining photoreceptors, images captured by a camera are projected onto the retina from augmented-reality glasses using pulsed near-infrared light. This design avoids the use of bulky electronics and wiring, thereby greatly reducing the surgical complexity and enabling scaling the number of photovoltaic pixels to thousands. Many features of the natural retinal signal processing are preserved in this approach, and spatial resolution matches the pixel pitch (so far 100 μm pixels in human patients, and 50 μm in rodents). For a broad acceptance of this technology by patients who lost central vision due to Age-Related Macular Degeneration, visual acuity should exceed 20/100, which requires pixels smaller than 25 μm. I will present a 3-dimensional electro-neural interface scalable to cellular dimensions and discuss the outlook and challenges for future developments.


 AP483 Optics and Electronics Seminar Series 2019-20 (Sponsored by Ginzton Laboratory, SPRC, Applied Physics, Physics, and HEPL).

Date and Time: 
Monday, February 24, 2020 - 4:15pm
Venue: 
Spilker 232

AP 483 Seminar Series presents "Taking the Humble FBG on a Voyage of Discovery from the Lab Bench to the Hospital and Beyond"

Topic: 
Taking the Humble FBG on a Voyage of Discovery from the Lab Bench to the Hospital and Beyond
Abstract / Description: 

Fiber Bragg gratings (FBGs) emerged almost magically in 1978. Since then, they have developed from being primarily of academic interest, to being one of the most versatile photonic components for both telecommunications and sensing. 

I was lucky enough to get introduced to photonics during the early years of discovery and experimentation with FBGs and ended up making FBG components for telecommunications. Jumping forward a few decades, I had moved away from telecommunications and had started to dabble with free space optical sensing. Then, during a chance meeting over a beer in Sydney, I was asked, rather naively, if it was possible to use optical fiber to monitor what goes on in the esophagus when we swallow. This set me off on an entirely new path and, pulling together some ideas from telecoms, and some basic mechanical engineering, my team ended up developing a range of sensors for monitoring pressure in the human digestive tract. 

Being able to detect swallowing disorders quickly led to monitoring in other regions of the gut, like the colon and small bowel, and, together with colleagues from Flinders Medical Center, we provided some details of the inner workings of the human gastrointestinal tract. Thus, the fiber optic catheter was born. This device kept me busy for almost 10 years, during which time we worked closely with clinical research groups to write a whole new chapter on how the gut works.

The next ‘Eureka’ moment came when we had to develop a temperature independent version of our sensor, initially for monitoring pressure beneath bandages. The very simple design that resulted worked well for sub-bandage measurements but has also become a key technology that has moved to applications in aerospace, pipeline monitoring, and mining.

When I started working in optics, I never thought I'd end up monitoring what makes your stomach growl when hungry, how air flows across an airplane wing, or detecting pressure transients in water pipes. 

During this talk I will explain how our basic transducers work and will then describe the applications they are now being applied to, demonstrating how the humble FBG has opened up the scope and reach of fiber-optic sensing.


 

AP483 Optics and Electronics Seminar Series 2019-20 (Sponsored by Ginzton Laboratory, SPRC, Applied Physics, Physics, and HEPL).

Date and Time: 
Monday, February 10, 2020 - 4:15pm
Venue: 
Spilker 232

AP 483 Seminar Series presents "Non-Hermitian Photonics: Optics at an Exceptional Point"

Topic: 
Non-Hermitian Photonics: Optics at an Exceptional Point
Abstract / Description: 

In recent years, non-Hermitian degeneracies, also known as exceptional points (EPs), have emerged as a new paradigm for engineering the response of optical systems. At such points, an N-dimensional space can be represented by a single eigenvalue and one eigenvector. As a result, these points are associated with abrupt phase transitions in parameter space. Among many different non-conservative photonic configurations, parity-time (PT) symmetric systems are of particular interest since they provide a powerful platform to explore, and consequently utilize, the physics of exceptional points in a systematic manner. In this talk, I will review some of our recent works in the area of non-Hermitian (mainly PT-symmetric) active photonics. For example, in a series of works, we have demonstrated how the generation and judicial utilization of these points in laser systems can result in unexpected dynamics, unusual linewidth behavior, and improved modal response. On the other hand, biasing a photonic system at an exceptional point can lead to orders of magnitude enhancement in sensitivity, an effect that may enable a new generation of ultrasensitive optical sensors on-chip. Non-Hermiticity can also be used as a means to promote or single out an edge mode in photonic topological insulator lattices. Rotation sensors play a crucial role in a diverse set of applications associated with navigation, positioning, and inertial sensing. Most optical gyroscopes rely on the Sagnac effect induced phase shift that scales linearly with the rotational velocity. In ring laser gyroscopes (RLGs), this shift manifests itself as a resonance splitting in the emission spectrum that can be detected as a beat frequency. The need for evermore precise RLGs has fueled research activities towards devising new approaches aimed to boost the sensitivity beyond what is dictated by geometrical constraints. In this respect, attempts have been made in the past to use either dispersive or nonlinear effects. Here, we propose a new scheme for ultrasensitive laser gyroscopes that utilizes the physics of exceptional points. By exploiting the properties of such non- Hermitian degeneracies, we show that the rotation-induced frequency splitting becomes proportional to the square root of the gyration speed, thus enhancing the sensitivity to low angular rotations by orders of magnitudes. We will then describe a possible modification of a standard RLG to support an exceptional point and measure the resulting enhanced sensitivity in the proposed system.


 

Date and Time: 
Monday, January 27, 2020 - 4:15pm
Venue: 
Spilker 232

AP 483 Seminar Series presents "Where Are We Heading: A Brief History and Future of Navigation"

Topic: 
Where Are We Heading: A Brief History and Future of Navigation
Abstract / Description: 

- tba -


 

AP483 Optics and Electronics Seminar Series 2019-20 (Sponsored by Ginzton Laboratory, SPRC, Applied Physics, Physics, and HEPL).

Date and Time: 
Monday, January 13, 2020 - 4:15pm
Venue: 
Spilker 232

AP 483 & AMO Seminar Series presents "Quantum Acceleration of Electromagnetic Axion Searches"

Topic: 
Quantum Acceleration of Electromagnetic Axion Searches
Abstract / Description: 

The QCD axion, which solves the strong CP problem in QCD, is one of the best motivated dark-matter candidates. I will discuss efforts to develop electromagnetic searches for QCD axion dark matter with masses below 1 micro-eV, including the Dark Matter Radio Cubic Meter experiment, which will probe the QCD axion band over 1.5 orders of magnitude in axion mass. However, full coverage of the QCD axion band will not be possible without acceleration by using quantum measurement techniques, which can be used to evade the standard quantum limit by the exploitation of quantum correlations in the electromagnetic signals. While photon counting is a useful technique to evade the SQL at masses above 1 micro-eV, it is not a useful technique at lower mass ranges. I will describe Quantum Upconverters, which convert signals from DC up to ~300 MHz to the microwave frequency range. Quantum upconverters can be used to implement techniques including backaction evasion to outperform the Standard Quantum Limit at the RF frequencies probed by DM Radio. They can also be used to improve electromagnetic sensing of nuclear spins for NMR-based detection schemes (including CASPEr).

(This seminar series is sponsored by Ginzton Laboratory, SPRC, Applied Physics, Physics, and HEPL)

Date and Time: 
Monday, March 2, 2020 - 4:15pm
Venue: 
Spilker 232

Pages

Subscribe to RSS - Applied Physics / Physics Colloquium