Georgios Varnavides

Quilt with Smith tiles pattern and vibrant colors (left), and its FFT (right).

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!

a 2x3 grid of Smith / Carlson / N6 tiles (top) and their corresponding FFT (bottom). The patterns exhibit considerable amount of diffuse scattering.

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 🧪

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

🚨 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...

Curious Beams Lab Logo: Converged electron probe revealing a nanobeam diffraction pattern, in the style of an engineering drawing blueprint.

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

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

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).

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...

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...).

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... 🧪🔬

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

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 🚀

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...

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...

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

Cal bears logo made from illuminated dots on a black background.

🧪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...

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