Mikhail Kats
@mickeykats.bsky.social
Optics/photonics researcher, applied physicist, and faculty at the University of Wisconsin - Madison. Personal account + opinions
Was @mickeykats on Twitter
Was @mickeykats on Twitter
Brittle starfish and trilobites, Ordovician period, about 450 million years old
November 23, 2025 at 8:36 PM
Brittle starfish and trilobites, Ordovician period, about 450 million years old
Just remembered (and looked up) my thoughts on this clip from 2021* and the way in which people over-apply Feynman's point
*I do miss old twitter
*I do miss old twitter
November 21, 2025 at 6:54 AM
Just remembered (and looked up) my thoughts on this clip from 2021* and the way in which people over-apply Feynman's point
*I do miss old twitter
*I do miss old twitter
Just remembered "garfield minus garfield", where Garfield is removed from the comic strips, so it's basically just Jon going insane
November 19, 2025 at 4:15 AM
Just remembered "garfield minus garfield", where Garfield is removed from the comic strips, so it's basically just Jon going insane
Very little Waymo expansion across the midwest =( www.understandingai.org/p/waymos-nex...
November 19, 2025 at 12:30 AM
Very little Waymo expansion across the midwest =( www.understandingai.org/p/waymos-nex...
This work was led by Rabeeya Hamid in our group, and is the result of a long collaboration with Dan Congreve's group at Stanford, supported by the DARPA ENVision program advanced.onlinelibrary.wiley.com/doi/10.1002/...
November 17, 2025 at 9:56 PM
This work was led by Rabeeya Hamid in our group, and is the result of a long collaboration with Dan Congreve's group at Stanford, supported by the DARPA ENVision program advanced.onlinelibrary.wiley.com/doi/10.1002/...
We demonstrated an optical system that enables upconversion imaging from 750-930 nm into the visible, at incident infrared intensities down to 10^-6 Watt/cm^2 at the input aperture, while preserving high spatial resolution. No external power or pump laser was used to aid the upconversion process.
![NIR-to-visible upconversion imaging using a bulk heterojunction (BHJ) thin film. a) The upconverting device consists of a BHJ of organic molecules Y6 and DBP-doped rubrene, sealed between two glass pieces using epoxy glue[32, 33] to prevent oxygen ingress. b,c) Molecular diagram (b) and energy diagram (c) of TTA upconversion in the Y6/rubrene/DBP BHJ. Y6 absorbs incident NIR photons to generate excited singlets (S1), which diffuse to the interface between Y6 and rubrene. At this interface, singlets transform into free charges and recombine to form charge-transfer states at the interface, which can then transfer to rubrene as molecular triplets (T1). These triplets combine via TTA in rubrene to produce a high-energy singlet, which transfers into DBP and then emits a high-energy photon via photoluminescence. d) Images of the upconverting thin film under ambient light are shown with (bottom) and without (top) NIR laser (λ = 852 nm) illumination. e) The upconverter is placed at the intermediate focal plane of a Keplerian lens system. This configuration preserves the relative angles between rays, θ, across the upconversion process, and therefore enables upconversion imaging. f) Schematic of the imaging setup used for transmission-mode imaging of an Air Force resolution target. g) Image captured using the setup in (f) with 1.17 magnification between the object and the image, using incoherent broadband illumination. Resolution groups 4 and higher are highlighted on the right. The scale bars indicate the dimensions of the image on the upconverter.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:abkp4sglznvkptyncrltve6t/bafkreicmgu2jcbtei44zyg54eqllbcfkzinne5qnaewgygmxja3mtmojcq@jpeg)
November 17, 2025 at 9:55 PM
We demonstrated an optical system that enables upconversion imaging from 750-930 nm into the visible, at incident infrared intensities down to 10^-6 Watt/cm^2 at the input aperture, while preserving high spatial resolution. No external power or pump laser was used to aid the upconversion process.
Our paper just out in Advanced Functional Materials: "Photonic engineering enables all-passive upconversion imaging with low-intensity near-infrared light" advanced.onlinelibrary.wiley.com/doi/10.1002/... 💡🧪
November 17, 2025 at 9:55 PM
Our paper just out in Advanced Functional Materials: "Photonic engineering enables all-passive upconversion imaging with low-intensity near-infrared light" advanced.onlinelibrary.wiley.com/doi/10.1002/... 💡🧪
The overall vision of bluesky, of a social network on an open protocol with account portability, is really great, and is the reason I'm here
But my impression is that there is no vision for growth of the network anymore. It's a shame
But my impression is that there is no vision for growth of the network anymore. It's a shame
November 17, 2025 at 1:46 AM
The overall vision of bluesky, of a social network on an open protocol with account portability, is really great, and is the reason I'm here
But my impression is that there is no vision for growth of the network anymore. It's a shame
But my impression is that there is no vision for growth of the network anymore. It's a shame
Cool security feature
November 17, 2025 at 12:14 AM
Cool security feature
'The term ‘‘affiliation’’ means any affiliation, ...' is really quite the turn of phrase
It could be interpreted to mean almost anything
It could be interpreted to mean almost anything
November 15, 2025 at 5:14 PM
'The term ‘‘affiliation’’ means any affiliation, ...' is really quite the turn of phrase
It could be interpreted to mean almost anything
It could be interpreted to mean almost anything
Sure.
Say you have the Sun and Earth, and you surround them with perfect mirrors, such that light from the sun always reaches the Earth.
The Earth can't become hotter than the Sun, because once the Earth heats up, it starts glowing too. The hottest the Earth can get is the temperature of the Sun
Say you have the Sun and Earth, and you surround them with perfect mirrors, such that light from the sun always reaches the Earth.
The Earth can't become hotter than the Sun, because once the Earth heats up, it starts glowing too. The hottest the Earth can get is the temperature of the Sun
November 13, 2025 at 3:10 AM
Sure.
Say you have the Sun and Earth, and you surround them with perfect mirrors, such that light from the sun always reaches the Earth.
The Earth can't become hotter than the Sun, because once the Earth heats up, it starts glowing too. The hottest the Earth can get is the temperature of the Sun
Say you have the Sun and Earth, and you surround them with perfect mirrors, such that light from the sun always reaches the Earth.
The Earth can't become hotter than the Sun, because once the Earth heats up, it starts glowing too. The hottest the Earth can get is the temperature of the Sun
Working on a letter for the NDSEG fellowship, and this is kind of a bonkers requirement for a letter, no?
November 12, 2025 at 5:01 PM
Working on a letter for the NDSEG fellowship, and this is kind of a bonkers requirement for a letter, no?
In the aurora, both reds and greens come from fluorescence from oxygen, mostly the from the 1S excited state (green) and from the 1D excited state (red)
The 1D state has a lifetime of >150 seconds, whereas the 1S state has a lifetime of ~1 second
The 1D state has a lifetime of >150 seconds, whereas the 1S state has a lifetime of ~1 second
November 12, 2025 at 5:14 AM
In the aurora, both reds and greens come from fluorescence from oxygen, mostly the from the 1S excited state (green) and from the 1D excited state (red)
The 1D state has a lifetime of >150 seconds, whereas the 1S state has a lifetime of ~1 second
The 1D state has a lifetime of >150 seconds, whereas the 1S state has a lifetime of ~1 second
The aurora is off the hook (Madison, WI, under the city lights)
November 12, 2025 at 3:33 AM
The aurora is off the hook (Madison, WI, under the city lights)
Now that's what I'm talking about
November 12, 2025 at 3:26 AM
Now that's what I'm talking about
Aurora over the house =)
November 12, 2025 at 1:58 AM
Aurora over the house =)
Well this is substantial
November 12, 2025 at 1:35 AM
Well this is substantial
And, of course, now I am lost in Wikipedia links, and just learned that the Great Wave off Kanagawa is probably supposed to be a rogue wave en.wikipedia.org/wiki/Rogue_w...
November 11, 2025 at 6:28 AM
And, of course, now I am lost in Wikipedia links, and just learned that the Great Wave off Kanagawa is probably supposed to be a rogue wave en.wikipedia.org/wiki/Rogue_w...
Fall delayed, but not canceled
November 9, 2025 at 3:54 PM
Fall delayed, but not canceled
We here in Madison do not do a good job celebrating this, but we should:
![ON THE EINSTEIN PODOLSKY ROSEN PARADOX*
]. S. BELL
Department of Physics, University of Wisconsin, Madison, Wisconsin
(Received 4 November 1964)](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:abkp4sglznvkptyncrltve6t/bafkreihgu3mbd6tjnqqq3ef4d2fotmriylc35xolyxui6mlamg3hmr5gru@jpeg)
November 7, 2025 at 10:09 PM
We here in Madison do not do a good job celebrating this, but we should:
Had to look these up
November 3, 2025 at 7:36 PM
Had to look these up
Advanced use of pillows and blankets
November 1, 2025 at 6:33 PM
Advanced use of pillows and blankets
I'd like to trade schedules with the dog for a few days
October 30, 2025 at 12:48 AM
I'd like to trade schedules with the dog for a few days