Department of Physics and Astronomy, San Francisco State University

05/07/2026

San Francisco State University
Physics & Astronomy Colloquium Series
Monday, May 11, 2026
SEIC 210, 3:30 PM

Speaker: Prof. Xiangdong Zhu (UC Davis)

Let There Be light - Materials studies using linear optics that exploits various symmetries

When light is incident on a solid material, its electromagnetic fields drive electrons in the material so that the charge density changes accordingly. Those changes that vary linearly with the fields are linear optical responses. The re-radiation from these responses can be used to characterize the solid material in question. Most linear optical responses only cause small perturbations to light reflection and transmission, yet they reveal most interesting properties of the material. I will show how effects from these perturbative linear responses on optical reflection can be obtained using a simple perturbation treatment. And by taking advantage of symmetry properties that distinguish one material from another or one phase of a material from another phase of the same material, we can learn a great deal about materials using linear optical techniques.

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04/30/2026

San Francisco State University
Physics & Astronomy Colloquium Series
Monday, May 4, 2026
SEIC 210, 3:30 PM

Speaker: Dr. Junze Zhou (Lawrence Berkeley National Lab)

"Nanoimprinted Scanning Probe for Enhanced Spectroscopies and Nanoimaging on 2D Excitons and Plexcitons"

Optically active scanning probes simultaneously measure nanoscale topography and optical spectra with sub-diffraction spatial resolution. This capability is critical for elucidating how both intrinsic material properties and artificially engineered structures influence macroscopic functionality in low dimensional systems. In this talk, I will introduce a novel scanning probe fabricated using a cost-effective and scalable nanoimprinting approach, enabling correlated spatial, spectral, and temporal measurements in a single platform. I will then discuss how the nanoimprinted probe, together with tailored plasmonic cavities, enhances the optical response of 2D excitons in atomically thin materials, enabling probing dark excitons, strain-localized states, and the strong exciton-cavity interaction underlying plexciton formation.

04/17/2026

San Francisco State University
Physics & Astronomy Colloquium Series
Monday, April 20, 2026
SEIC 210, 3:30 PM

Speaker: Maureen Savage (UCSC Observatories)

"Science Instrument and Observatory Development - A perspective"

Perspectives on observatory and instrument development including work at San Francisco State University, NASA Ames Research Center, and UC Santa Cruz. Discussion of current existing and future projects to enhance observatory operations, as well as how SFSU physics and astronomy disciplines can enable support for critical emerging technologies in fusion power and space weather. I will include some details regarding the Stratospheric Observatory For Infrared Astronomy (SOFIA), Thirty Meter Telescope (TMT), and UC Santa Cruz current projects for Keck (SCALES, the Keck Adaptive Secondary). I also hope to include information on the International Thermonuclear Experiment Reactor (ITER) and a planned Space weather (small sat) project.

04/09/2026

San Francisco State University
Physics & Astronomy Colloquium Series
Monday, April 13, 2026
SEIC 210, 3:30 PM

Speaker: Dr. Anne Metevier (Lick Observatory/UCSC)

"Expanding Education Programs through Lick Observatory and UC Observatories"

Lick Observatory is home to a suite of historic telescopes and active research telescopes atop Mount Hamilton near San Jose. The University of California Observatories stewards Lick Observatory and is significantly expanding Lick's education programs, particularly at the college level, thanks to a generous grant from the Gordon and Betty Moore Foundation. Goals of this expansion include broadening access to the observatory through impactful educational experiences that provide exposure to research processes and, in some cases, to observatory careers. Lick's college-level programs are run through a new consortium of Bay Area community colleges and Cal State campuses that collaborate with Lick, called the ASTRAL Consortium. Anne Metevier will describe ASTRAL's programs, including ways that students and faculty at San Francisco State can get involved. She will describe the astronomy and education research-based underpinnings for the programs, how the programs have been designed to engage both STEM and non-STEM students, and how professional development training for graduate students and postdocs is woven into the instruction of some of the programs, providing near-peer interactions.

04/06/2026

San Francisco State University
Physics & Astronomy Colloquium Series
Monday, April 6, 2026
SEIC 210, 3:30 PM

"The Ghosts of Stars: The Heaviest Elements Found in Nature and Where They Are Born"

Erin Huntzinger, PhD Candidate, UC Davis

Over its 14-billion-year history, the composition of the universe evolved in chemical complexity, starting with hydrogen and over time forming nearly all elements on the periodic table. Elements heavier than iron are produced by neutron capture processes, namely the slow neutron capture process (s- process) and the rapid neutron capture process (r-process). The heaviest elements produced in nature, radioactive actinides such as thorium and uranium, are formed solely by the r-process. While the s-process is known to occur in stars on the asymptotic giant branch, the astrophysical sites of the r-process remain uncertain. So far, neutron star mergers (NSMs) are the only confirmed sites for the r-process, but it is not yet known whether or not NSMs can fully account for the abundance of r-process elements we observe in the Milky Way. Are NSMs the dominant site of r-process production? Where else can the r-process occur? One way we can begin to answer this question is by investigating heavy element abundances derived from stellar observations. In this talk, I will discuss how we use these abundances to trace the production of r-process elements in the Galaxy over time, along with the challenges it presents in different populations of stars.

03/27/2026

San Francisco State University
Physics & Astronomy Colloquium Series
Monday, March 30, 2026
SEIC 210, 3:30 PM

Prof. Luan Ghezzi (Volongo Observatory - UFRJ)

"The connections between the chemical abundances of stars and their exoplanetary systems"

Abstract: The stellar metallicity influences the occurrence of giant and small hot exoplanets. However, the role of elements other than iron on planetary formation is still unclear. In this talk, I will discuss the relations between the abundances of 13 chemical elements (Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, and Cu) for a sample of 561 Kepler exoplanet-hosting stars and the radii and orbital periods of their planets. These possible connections are investigated through comparisons between stars that host different planetary systems. I will also discuss the role of alpha elements in the formation of giant planets and examine the depletion of refractory elements in the Sun. The analysis of 25 solar twins in our sample suggests that this chemical peculiarity might be caused by processes other than planetary formation.

03/18/2026

Our Physics & Astronomy Club rebranded a few years ago, and we absolutely love their new name: S.P.A.C.E.: Students of Physics & Astronomy - a Community for Everyone! We ask that you please make a donation so that they can host events and field trips to support their "ad astra" journey!

Help SPACE bring students together through physics & astronomy. Support us on !

03/18/2026

Today is Gator Giving Day! Please help us complete the renovation of our Charles F. Hagar Planetarium at SF State! This planetarium is used to teach the wonders of the night sky to SF State students and K12 students from around the Bay Area. We also have a very popular bilingual English-Spanish night called Noche de Estrellas! We are specifically raising funds to install full-dome video projection so that we can show relevant images and movies that complement the star projections.


https://giving.sfsu.edu/schools/SanFranciscoStateUniversity/gator-giving-day-2026/pages/cose/planetarium/?a=9893250

Transforming SF State's Hagar Planetarium into a 21st Century Hub for STEM Education and Outreach

The Charles F. Hagar Planetarium has served SF State and the Bay Area for more than 50 years. Over 100,000 SF State students, San Francisco school children, and members of the public have experienced the beauty of the night sky and witnessed the Milky Way as it appears far from city lights in this unique facility nestled in the heart of Thornton Hall. Through interactive experiences in labs, school shows and public shows, they have had their questions about the planets, stars, and the Universe answered. For decades, the planetarium has also been an inspiring training ground for hundreds of undergraduate and graduate students interested in astronomy education and outreach -- many of whom have gone on to careers as science educators in the Bay Area and beyond.

Help us build on this proud legacy by supporting our planned renovation!

To create a stimulating space that inspires SF State students for the coming decades and provide a modern training ground to attract and prepare Bay Area STEM educators, we are embarking on a complete renovation of the planetarium beginning this summer. As part of this, a new state-of-the-art star projector is coming to us from Zeiss in Germany.

To make the planetarium a 21st-century facility, one more critical piece is needed.

The refurbished planetarium we envision will also feature full-dome video projection. Visitors will not only be able to see the night sky as it appears from Earth, they will also be able to travel to other planets and fly through the Milky Way and beyond using immersive video that covers the entire dome. SF State student presenters who train in the planetarium will be using of state-of-the-art NASA-sponsored software that incorporates images and data from the latest telescopes and satellites. But we need the hardware to go with it!

Join me and make a gift to Gator Giving Day 2026

03/16/2026

San Francisco State University
Physics & Astronomy Colloquium Series
Monday, March 16, 2026
SEIC 210, 3:30 PM

Dr. Lynn Cominsky (Prof., Sonoma State U.)
Gravitational Waves: The Discovery that won the 2017 Nobel prize in Physics

Abstract: In 1915, Albert Einstein published his General Theory of Relativity. In this theory, gravity is not a force, but a property of spacetime in the presence of massive objects. A century later, on September 14, 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) received the first confirmed gravitational wave signals. Now known as GW150914, the event represents the coalescence of twodistant black holes that were previously in mutual orbit. LIGO’s exciting discovery provides direct evidence of what is arguably the last major unconfirmed prediction of Einstein’s Theory and has launched the new field of gravitational-wave astronomy. Prof. Lynn Cominsky
from Sonoma State University will present an introduction to LIGO, gravitational waves and black holes. She will also discuss the gravitational wave detection results reported from LIGO.

03/08/2026

San Francisco State University
Physics & Astronomy Colloquium Series
Monday, March 9, 2026
SEIC 210, 3:30 PM

Dr. Chris Gordon (Senior Lecturer, U. Canterbury)
Title: Probing the nature of dark matter using super massive black holes

Abstract: Axions are hypothetical, extremely light particles originally proposed to solve the strong-CP problem in QCD, and they are also a well-motivated candidate for the Universe’s dark matter. In many axion dark-matter scenarios, the axion density is expected to clump early into dense “miniclusters” and then merge into somewhat larger bound clumps (“minihalos”), with typical masses in the asteroid-to-planetary range. In the Milky Way, repeated stellar flybys and disk passages can disrupt these structures, altering the local distribution of axions and the expectations for laboratory searches. I will present a new treatment of this disruption that accounts for multiple encounters and for the minihalos’ internal relaxation between encounters, calibrated with orbit ensembles evolved in a Galactic potential. We find that stellar interactions are substantially more destructive than previously estimated: minihalos retain only ∼ 30% of their mass near the Solar System, compared to earlier values of ∼ 60%. I will explain the physical origin of this enhanced stripping, and discuss what it implies for the local smooth axion density and for microwave-based axion detection experiments.