Georgios Varnavides
@gvarnavides.bsky.social
180 followers 280 following 14 posts
Assistant Professor of Imaging Physics, Delft University of Technology | Co-editor of elementalmicroscopy.org
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gvarnavides.bsky.social
Introducing the Curious Beams Lab — where we use electron beams and advanced algorithms to image the structure and function of materials at the nanoscale 🔬

PhD & postdoc openings coming soon — stay tuned!
#TUDelft #ElectronMicroscopy #ComputationalImaging
Curious Beams Lab Logo: Converged electron probe revealing a nanobeam diffraction pattern, in the style of an engineering drawing blueprint.
Reposted by Georgios Varnavides
gvarnavides.bsky.social
The code to generate the Smith / Carlson / N6 tiles is adapted from Ned Batchelder's brilliant blog post: nedbatchelder.com/blog/202208/...

Also, here's the picture of the mentioned quilt and its FFT!
Quilt with Smith tiles pattern and vibrant colors (left), and its FFT (right).
gvarnavides.bsky.social
Went to a cool BAMPFA exhibit this weekend, on African American quilt making! Recognized one of the patterns as a Truchet tiling, and wanted to know what its FFT would look like. Would the symmetry pop up? Would the diffuse scattering??

That led to this fun exploration of Smith/Carlson/N6 tilings 🧪
a 2x3 grid of Smith / Carlson / N6 tiles (top) and their corresponding FFT (bottom). The patterns exhibit considerable amount of diffuse scattering.
gvarnavides.bsky.social
This fully-funded 4-yr PhD is part of a broader collaboration with ASML, ARCNL, and TU Delft, combining computational imaging, BSE/SE modeling, and inverse algorithms for high-res, low-voltage SEM!

#SEM #phd #computationalimaging #electronmicroscopy #curiousbeams @imphys-tudelft.bsky.social
gvarnavides.bsky.social
🚨 We’re hiring!

Join the Curious Beams Lab at TU Delft as one of our first PhDs and help develop the next generation of diffractive imaging in SEM — pushing surface-sensitive nanoscale characterization to new limits 🔬🧪

Please repost & share with your network! 🙏

careers.tudelft.nl/job/Delft-Ph...
PhD Position Developing Diffractive Imaging in Scanning Electron Microscopy for Inspection/Metrology
PhD Position Developing Diffractive Imaging in Scanning Electron Microscopy for Inspection/Metrology
careers.tudelft.nl
gvarnavides.bsky.social
Introducing the Curious Beams Lab — where we use electron beams and advanced algorithms to image the structure and function of materials at the nanoscale 🔬

PhD & postdoc openings coming soon — stay tuned!
#TUDelft #ElectronMicroscopy #ComputationalImaging
Curious Beams Lab Logo: Converged electron probe revealing a nanobeam diffraction pattern, in the style of an engineering drawing blueprint.
gvarnavides.bsky.social
Thrilled to finally share that I'll be joining TU Delft this fall as an Assistant Professor in the Imaging Physics department 🙌🏼 Excited to join such a vibrant, cross-disciplinary community and grateful to the mentors and colleagues who've supported me along the way 🙏🏼

@imphys-tudelft.bsky.social
gvarnavides.bsky.social
The main takeaway is that formulating it this way, it follows that tcBF/parallax is a quadratic approximation to phase-compensated SSB (upsampling then follows naturally from that).
gvarnavides.bsky.social
The formalism in-fact is slightly different, looping over the virtual BF images instead of spatial frequencies.

Pseudocode and discussion here: www.elementalmicroscopy.com/articles/EM0...

and full code here:
github.com/ophusgroup/q...
gvarnavides.bsky.social
Haha, indeed -- if only we had a better name for "phase-compensated" SSB (meaning using the complex-valued aperture overlap gamma function, here doi.org/10.1016/j.ul...).
gvarnavides.bsky.social
Split figures are great for papers. For talks, interactive sliders are better 🙌

Here, demoing the upsampling capabilities of tilt-corrected BF STEM and direct ptychography on a beam-sensitive MOF dataset!

elementalmicroscopy.com/articles/EM0... 🧪🔬
gvarnavides.bsky.social
Super proud of this work, which showcases modern scientific publishing for open science 🧪

Inspired by the insights of the interactive CTF widgets, we propose a novel phase-retrieval algorithm which achieves robust information transfer on sub-sampled datasets 🙌

@elementalmicrosc.bsky.social
Reposted by Georgios Varnavides
elementalmicrosc.bsky.social
Hey there 🦋🧪, we're a new open access microscopy journal and wanted to introduce ourselves! EM aims to modernize scientific publishing for microscopy, by prioritizing open science, transparency, and accessibility and using open-source formats and interactive notebooks 🙌

@curvenote.com @mystmd.org 🚀
gvarnavides.bsky.social
Attending the APMC 2025 in Brisbane, and interested in learning how to simulate and analyze 4D-STEM data? There's still time to register for the 4D-STEM workshop and learn about strain and orientation mapping, differential phase contrast, ptychography, and more!

www.apmc13-2025.org/conference-w...
gvarnavides.bsky.social
Needed to demonstrate this fun example of solving Sudoku puzzles with projection set algorithms for a workshop I'm teaching. Continuously impressed with how easy it is to get to a working demo with wasm + @marimo.io slides 🙌 🧪

marimo.io/p/@gvarnavid...
Reposted by Georgios Varnavides
curvenote.com
Monday 9th 15:00 Open Science Pavilion - Big Screen, Exhibit Hall
Join @row1.ca for a session on Publishing Computational Research Session

#OpenScience #Jupyter @mystmd.org
Reposted by Georgios Varnavides
berkeleylab.lbl.gov
🧪Constrained optimization tiling of the Cal bears logo, using simulated differential phase-contrast imaging of strontium titanate atoms.

🔬 Captured for @molecularfoundry.bsky.social #Nano Art Contest.

📷 Georgios Varnavides, @ucberkeleyofficial.bsky.social

More: foundry.lbl.gov/2024/10/21/a...
Cal bears logo made from illuminated dots on a black background.
gvarnavides.bsky.social
Hello 🧪🦋 New here, so figured I’d introduce myself! I’m a postdoctoral researcher @berkeleylab.bsky.social exploring the mesmerizing corners of diffractive imaging ✨

Short clip of my new favourite teaching demo: nanofabricated Fourier atlas by @hovden.bsky.social lab 🙌

📸: @juliedactyl.bsky.social