Events at Physics
Events on Wednesday, September 21st, 2022
- Thesis Defense
- Micro- and nano-optical components for quantum technologies
- Time: 10:00 am
- Place: Engineering 3609 and virtual-https://uwmadison.zoom.us/j/94242686133?pwd=MjhURDFhVFJjYU1VY25Vcit5dElZZz09
- Speaker: Zhaoning April Yu , Physics PhD Graduate Student
- Abstract: The booming of quantum technologies offers exciting opportunities in the field of optics. This thesis includes our effort to address three optical challenges when building a quantum repeater or a quantum chemical sensor, they are: (1) how to engineer diffraction gratings for trapping cold atom clusters; (2) how to efficiently generate optical bottle beams using a single surface-patterned chip; and (3) how to extract fluorescence from color centers in diamond without damaging the diamond surface. To interact with a small (atom-scale) quantum system, miniaturized optical components are often needed with micro- or nanometer structuring. Such compact structuring poses requirements in both simulation and fabrication methods. On the one hand, when designing and evaluating a micro- or nano optical component, unlike conventional bulky optics where light can be approximated as rays, the electromagnetic field must be calculated with nm-scale spatial resolution. On the other hand, when making a micro- or nano optical component, conventional mechanical polishing can not provide sufficient accuracy, thus researchers resort to advanced lithography techniques (such as electron-beam lithography, laser lithography) which has already been used in the semiconductor industry. The methods are introduced and discussed in details for each application scenario. By using finite-difference time-domain (FDTD) simulation method and electron-beam lithography fabrication method, we demonstrate: (1) a grating chip for trapping dual atomic species; (2) an optical metasurface for generating a bottle beam array with a single Gaussian beam luminance; and (3) a silicon light extractor for enhancing the fluorescence collection from nitrogen-vacancy (NV) defects in diamond.
- Host: Mikhail Kats
- GREAT IDEAS DEI Reading Group
- GREAT IDEAS DEI coffee hour
- Time: 12:15 pm
- Place: Chamberlin 5280 or online at
- Abstract: We will be discussing this paper from Physical Review Physics Education Research: Postsecondary physics curricula and Universal Design for Learning:
Planning for diverse learners. We would like people to focus on the abstract, introduction, UDL framework and guidelines, methology and findings sections for the discussion. We will also go over an article summary and we welcome attendees who haven't had an opportunity to read the article.
GREAT IDEAS stands for Group for Reading, Educating, And Talking about Inclusion, Diversity, Equity, & Advocacy in Science. It is a multimedia reading group dedicated to amplifying the experiences of underrepresented groups in science and academia in order to become better advocates for our peers. GREAT IDEAS is open to everyone (students/ faculty/ staff/ etc), and all are welcome and encouraged to engage with the material and contribute to the discussions. To keep a welcoming and safe environment for everyone, we ask that everyone understand and adhere to our community guidelines for the discussions;. If you would like to submit an article for a future GREAT IDEAS discussion, you can do so on this form.
- Host: GMaWiP and Climate and Diversity Committee (contact Faizah Siddique or Cameron Kuchta with questions)
- R. G. Herb Condensed Matter Seminar
- Results of the SHAFT experiment
- Time: 3:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Alexander Gramolin, Riverlane
- Abstract: I present the results of the SHAFT experiment at Boston University to search for axion-like dark matter in the mass range from 12 peV to 12 neV. The experiment is sensitive to the oscillating magnetic field that would be sourced by an axion-like dark matter halo of our Galaxy interacting with a strong static magnetic field in the lab. We employ toroidal ferromagnetic cores made of powdered iron-nickel alloy to enhance the static magnetic field by a factor of 24. Using superconducting quantum interference devices (SQUIDs), we achieve a magnetic sensitivity of 150 aT/rtHz. This sensitivity allows us to improve, over a part of our mass range, the existing laboratory limits on the electromagnetic coupling of axion-like dark matter.
- Host: Robert McDermott