a brief physics distraction
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- Опубликовано: 5 ноя 2024
- Why not distract yourself from a doom scroll by thinking about photons?
The story of two-photon absorption.
Link to Patreon - one exclusive video per month: / acollierastro
I have merch-store.dftba.co...
I can't believe the two photons are polling neck and neck.
First hehe
captain please 😭
^^^ this guy, this is my kind of guy
You can't just say the thing lol
i can believe that the entire american population is the 'herd' that pollsters have lasso'ed at least in their own minds
This is 100% what I needed today. And tomorrow. And probably for the next week.
Don't worry, someone will be president for sure
probably the next few months 😭
For the next few weeks if he loses. He's not going to give up.
@@DanLamey-g5d or longer. If he lives long enough, that might be the only way for him to stay out of prison.
Same. I was almost afraid to even open RUclips, then I saw new Angela video and from that opening was thinking “Yes!!!! Definitely need a distraction” thanks Angela!
My internal monologue: ᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃᵃ
Dr. Angela: Hey, here's a fun story.
Me: Oh, that sounds like a nice distraction.
Dr. Angela: So it's the 1920s, and we're in Germany...
My internal monologue: ᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬᴬ
I’ll need one of these everyday for the next 4 years please
11:20 In her paper she called it "Der Simultanemission zweier Lichtquanten" which is roughly "The simultaneous emission of two light quanta" with "Lichtquanten" basically being the German precursor word to "photons." She also called it "zwei Quantensprüngen" or "two quantum leaps" which is lovely. She also talks about the inversion of this process, where "zwei Lichtquanten" (two light quanta) whose frequency sum is equal to the excitation frequency of the atom, act together to excite the atom.
Thank you, I was wondering this and it was distracting me from the video 😄
Thank goodness for Angela's little island of knowledge, civility and good humor.
I can't agree strongly enough.
She still hasn't told us if she's doing her particles in a space fortress or laboratory under the sea. At this point. I'm not packed for either and probable wont make it
thanks for the physics distraction, here's an even more brief engineering distraction:
Two photon absorption is also used in micro-scale 3d printing! They focus femtosecond laser pulses inside a material that polymerizes into a solid when it absorbs two photons, which lets them solidify a single point at the focus. Two-photon absorption lets them cure the material just at the focal point rather than the entire path the laser takes. Move around the focus in the shape of your object, and you get a solid part!
Also used in the security print business. Upconverting phosphors that do IR to visible emissions.
Thank you, Angela. I think a lot of us needed something like this today.
6:03 - Habilitation is a process at German universities to get your "licence to teach" - your venia legendi. It's a thing you do after your PhD and in the vast majority of cases also *after* a Post-Doc. It usually consists of a couple of years of research which you then have to publish like a doctoral thesis (usually as a cumulative thesis though). In the Anglo-saxon sphere you skip this whole step and become a Junior-Professor instead. In the alter years, the Junior-Prof track is also getting more common in Germany, but the "old" Habilitation track is still the more common one.
And fun bonus fact to think about, because it is fun to think about those things: If you get your Habilitation, you change the name of your doctorate: My Dr. rer. nat. for instance would then be a Dr. rer. nat. habil. Isn't that fun?
@@xBris But is that not just an extra title? What else does it change? Does it not just make it sense to get an extra title?
Also known as a Ponzi scheme to keep young scientists dependent on their professor and department.
@@xBrisand if you actually find a position to teach (for free) you can even write PD Dr. rer. nat. habil!
During grad school in austria I had this funny conversation with a colleague who was shocked when I told her I'd never heard of what a habil was and that nobody outside austria, germany and maybe italy knew or cared about it at all.
But then again, she was a legacy hire and her dad was a big shot consultant who had made his career by flexing his "Priv.-Doz. Dr. med. univ. et scient. med. Dr. med. MBA" (yes, two times Dr. med., really weird). But then again, Austria is basically still a monarchy in spirit and having many prestigious titles is very important for being taken seriously. Coming from an old democratic country where even lawyers don't really use their titles that was really a culture shock.
I don't understand most of what Angela says, but I cannot state how much I enjoy listening to her say it. The excitement just comes through beyond the words spoken.
My PhD thesis involved 2PA! I did not expect the topic to appear here. What a pleasant surprise.🤩 Thank you Dr. Collier.🎉
Awesome video! From a biologist here, 2 photon microscopy helps to image deep tissues because infrared light scatters less in tissue than visible light. Also since the only place that has enough excitation is the center of focus (as the lens focuses the infrared light into a little dot) you can observe any light that comes out of the tissue and assume it is from the center of focus. These two factors help to image deep inside tissues. longer wavelengths for 3x or 26x microscopy may penetrate tissues but you get into resolution problems as the imaging resolution is related to the wavelength of light.
@@rott921 doesn't resolution depend on the wavelength of the emitted light rather than the excitation wavelength?
And it might even be that much more timely if you live in a place where a Chips&Science Act has reinvigorated the manufacture of electronics on a 3nm or 4nm resolution. Google is happy to show us a bunch of cool cartoons of what we believe is happening in trench transistor MOSFETs, but I'm not seeing very many tunneling electron microscope images.
Bioengineer here, I came to wonder about resolving at such long wavelengths when dealing with very small structures!
I figured there were minimal advantages to increasing to 3-photon, and the two things I'm finding it being used over 2x are rapid volumetric scans (which seems like it's doing things that could be done with 2x, just maybe requiring repositioning of the sample a couple times) and photoisomerization of drugs for targeted pharmacology. Which seems like a big swing how much 3x is carving a niche for itself
@@marcosulzgruber6849 Resolution of the emited light yes. But it lowers the resolution of the focusing area, IE the section you light up becomes larger. I think I don't know enough about light or quantum to realy speak about these things.
German here. The title of Göppert‘s thesis translates to „About Elementary Acts with Two Quantum Leaps“.
Two Quantum Leaps. Oh boy!
Emotional support physics
It will never cease to amaze me that, through a bunch of very rigorous math, you can basically stumble upon a conclusion about reality, and years and even decades later it's confirmed through experimentation that, yes, that's indeed reality. That's the most fascinating aspect of physics to me, that there are times you can make discoveries before realizing you've made a discovery
Yes, but it's only after uncountable failed discoveries and ideas being shown faulty. Failures are nor lauded but they build up to the successes.
creativity is Wild when you have to constrain it. Impossible by definition, right?
Three-photon microscopy is a crowd
Good one. Hahaaaaaaaaaa
What a lovely gift this was right now!
Thanks Angela. This was very much needed right now
Arguably the greatest video ever posted to RUclips. Thank you.
A lifetime of study in under 23 minutes along with schematas explained, in very basic terms, is the sign of pure genuis. Of course I subscribed, I know a gold mine when I hit gold❤.
You'll love the rest. As a lifetime nerd, she helped me understand dark matter and the problem of string theory better than anything else ❤
You're such a fantastic creator and science communicator! Found your videos just a few months ago, and I keep enjoying your channel more and more!
Inject this into my veins on this most nerve racking of days.
👍
Habilitation is basically a second thesis you have to write before being allowed to become a professor in Germany. In the natural sciences this is a formality nowadays, and you can basically submit a summary of your articles you wrote as a post doc. In other subjects, e.g law, this can be a lot longer and take anpther couple years of research to complete. In that case it replaces doing post docs
But, but my TV gives me photons! (also, thank you for reminding people that the nazis are the bad guys two times. I don't think there is an upper limit with diminishing returns on that one, so we can, and should, all just keep on saying it)
I see “zweier Lichtquanten” (two light quanta) in MG-M’s paper, which is I believe more or less how we referred to it in English before the word photon caught on. These days in German I think you’d mainly see that wording only to describe what a photon is. They’d say Photon now (Photonen for plural), or rarely Foton. The super literal translation of the title is something like “over [meaning ‘on’/‘pertaining to’] elementary acts with two quantum jumps.”
In this context, "ueber" would commonly be translated as "about", just FYI
Or "concerning" if you want to go for the Tolkien flair
The title of the thesis is "On elementary actions with two quantum jumps" so I guess she would call them "Quantumsprüngen" (I like to read it as "quantum-springing" we should call it that).
I bet this is the best presentation of pondering on youtube.
Excellent distraction today (as noted by others...).
Yet, I oppose an apology for asking your final question!
Physics is ALL about asking the right questions to induce thought!
We all need to think more! Many thanks! :)
8:30 good god finally see the mystery spherical cow !!!! Worthy the trip.
I've literally been begging the cosmos for a new @acollierastro video in these dark, anxious times. Thank you. 🙏❤️
Thanks for this! I definitely did need a distraction today, and this was a fun one! Also thanks for finally showing me that famous beast I've been hearing about since I was a kid: the spherical cow! ☺ Finally, thanks for the all-too-timely reminder about who the bad guys are!
Thank you SO MUCH. This is exactly what I needed!
You are a savior and lady of mercy, Angela. TY for this. I am distracted.
Thank you for this.
I needed this right now. Thank you, Angela. ❤
Love the trex on the triple beam balance
In the last fifteen seconds of this video you can see her go though multiple stages of grief.
1. Denial - "Hey, this will totally distract me!"
2. Anger - "Nope, I'm thinking about it again. Gah!"
3. Barganing - "I'll think on this photon thing more, and if I think *really* hard it'll distract me."
4. Depression - "No, it doesn't work and it'll never work."
Acceptance was never reached from what I saw.
This is what I've been going through in the first 15 seconds of the video. I can't concentrate on this stuff right now 😭
Humans accept the nature of reality in single digit cycles of updates after the simulation ends.
That's kind of the whole point. So far, it's not been solved. That's why we're here. To accept it.
Angela's "grin and bear it" face is so adorable.
The bad guys harshed our mellow when we were briefly reminded that all of this brilliant physics was happening in Germany in the 1930s. Thankfully, Angela quickly got us refocused on the photons. Meanwhile, the text reminded us that even that nightmare came to an end thanks to the preponderance of good, courageous people.
@@MDfuego my interpretation is, she reached acceptance when she hit record ¯\_(ツ)_/¯
Okay, smart-but-liberal-arts guy here, you made me understand this and it feels awesome! Also, film school grad specifically, and get this: in photography, the smaller your lens's aperture, the longer your focal length, but the less light gets in. So you increase focus at the expense of brightness, just as you're saying with n-photon microscopy! Isn't that interesting? If you're shooting in low light you get shallower depth-of-field, but in bright sun your focal length is effectively infinity. Or if you want more focal length than you're getting, you need to *add light*. That's how I bring my photography knowledge to this quantum physics discussion! (Also my quick and dirty theory would be three photons being the best, because you can triangulate on the subject in three dimensions, but that's just a wild uninformed guess.)
I think you want to review the notions of focal length and depth of field a few more times smart-but-liberal-arts guy
THANK YOU ANGELA YOU ARE A SAINT
P.S. you're a really good story teller
Enjoyed the video! I’m a chemist that works with fluorescent materials. Similar processes to two photon absorption are triplet-triplet annihilation and lanthanide based up conversion. Again, they are processes that involve two photons in, one process out, but with extra steps haha.
I've used multiphoton microscopy for imaging live mice and literally cannot overstate how much better it is than single photon!
I'm freaking out 😢
I appreciate the distraction. Thank you!
0:10 kind of, but more often I need to find some way to STOP thinking entirely instead... like if my anxiety gets too bad, I have to do simple repetitive tasks for a few hours to calm down.
Simple repetitive tasks give me too much time to think... 😢
When my anxiety gets bad I need to put headphones into my ears and listen to podcasts (music won't do) to keep my brain distracted.
Thank you for the distraction! Much needed today.
This is great stuff! Nonlinear spectroscopy (including two-photon absorption) is basically what I do for a living, and you can get amazing data from experiments if you design them carefully. It's just a shame the math can be so painful at times 😅
Wow… ok, this is a masterwork. You pose a fascinating, vaguely solvable problem to your audience at… such a time as this. Maybe a few percent of your (likely more educated than average RUclips) audience will even hear the question, much less get nerd sniped by it. But lord, the whole thing reached me.
Excellent work. Wish I’d had you as a physics professor or TA.
Same. Grateful for Angela and truly impressed by the audience she attracts and the quality of comments.
00:00 Vampire Survivors is S+ in the tier list at its ability to distract for alarming stretches of time.
thank you Angela. you're an absolute hero.
I spend most of my day involved in such distraction. I pessimistically imagine that most of your audience does so with your videos.
can confirm
distractions keep me motivated
An interesting aside, my A/P professor's day job was doing Two Photon Excitation Microscopy on celluar proteins at Case Western Reserve University.
Thank to Angela, now I know what it really involved!
This babe always knows what's up, thank goodness for her
Yay - physics distraction - many thanks - cheers
I just opened RUclips thinking to myself, “I need a distraction right now that’s not political”.
Thank you for this! ❤
Ooh F*** I'm going to need a longer distraction (four years?)
Hey Angela, awesome video thank you :)
If you dont mind the nitpicking, as a physicist who also did some years of German, the german pronunciation of Göttingen sounds a bit like "guh - tea - ng - en"
Nothing wrong with pronouncing it like with an american intonation while speaking in american English but I thought you might be interested to know :)
Yes. I needed this today. I really needed this. Thank you so much.
So basically we just need to solve the attosecond laser problem and then we have pulses short enough to mess around and study 3+ photon absorption.
"The Nazis are the bad guys" ❤
Louder. Cause apparently we have to even say it
Bewildering it must be said. It makes me wonder who those people root for when they watch "Saving Private Ryan"?
Apparently it needs to keep being said the way this election is going.
I was not expecting the biggest laugh I've had in weeks from seeing Dr. Collier try (and only partially succeed) to think about photons!
Ahhhhhh I'm German and was so confused about where you were talking about until the text came up! Just fyi, Göttingen is pronounced kinda like "Gerting-in" in a british accent (as opposed to rhyming with "cotton gin" haha) Love your videos!
i was thinking Guh-ting-un.. But uh doesn't really cover it.
The ö sounds similar to the beginning of early, but stop before the r. G firstPartOf(early) tingen.
It took me a while to realize she was trying to say Göttingen. Some of the other German names also got mangled.
It sounds like it's those videos of trampolinists where they have their buddies jump down right as the one in the center hits, sending that one flying into the air.
Perfect timing for the video release
I've been hoping for a new video from you and this is the PERFECT time and purpose!!
This is my favorite of all your videos. Great job.
You are an intellectual treat for the dumbfounded❤.
dude I was literally just thinking please someone give me content that will engage my brain that isn't about politics and there you were, completely read for my need. thank you, so much.
one of my favorite humans
THANK F** goodness for this wonderful channel
Hey, Patrick.
What?
I thought of something even cooler than 2.
Let me hear it.
3!
*Intense giggling*
Well I was sufficiently distracted for 20 some minutes, thank you! Now back to the horrors ☺️
Wow, you have such an amazing ability to make a video precisely at the time that I need it, Angela.
Great video and a very welcome distraction! Another thing you can do with two-photon absorption is two-photon lithography, which is like the tiniest 3D-printing imaginable
I've seen four photon microscopy in papers, but it isn't as common as two or three. The big limitation is that most fluorophores need excitation at 300 - 600 nm, and it isn't easy to make an ultrafast laser with wavelengths above ~1800 nm (600 * 3). Another consideration is that you want to keep your wavelengths in the biological window to get good penetration depth (en.wikipedia.org/wiki/Near-infrared_window_in_biological_tissue).
I work on biological imaging using harmonic generation microscopy, which is very similar to multiphoton florescence but with even more virtual states.
Always super calming to have your videos in the background while I do other things :-) thanks for the new upload!!
Yes, I do need that. Thank you.
@21:30 consult xkcd. If a joke does not exist for N>3 photon absorption then it is against the -laws- laughs of nature.
One reason that two-photon imaging is useful is that, in addition to only producing absorption near the focal point of the light beam, it shifts the wavelength to a more convenient place. For biological applications, everything pretty much happens in water, so you need to use a wavelength where water is transparent. So basically the visible region, going a little into the UV and IR. So absorption of a large number of photons, in addition to being a very unlikely process would result in a wavelength way in the IR where water isn't transparent.
To be Franck, I Mayer may not have been Born to absorb this vid Dirac to the brain. Sorry if these puns are a Pauling.
Thank you for the wonderful respite from stressing over “the thing!”
Also what you mentioned in the end is exactly what I’m seeing in my non-linear optics class. NLO is great for spatial resolution BUT you are limited by the power of the laser that has to be huge in order to see 3 photon and 4 photon effects. Also this becomes quite interesting because NLO effects can be used to probe the symmetry of your material where you could probe not only dipoles but also quadrupoles, octupoles…You have a tensor that will indicate how the hyperpolarizability components in space change with the applied electric field…and it get’s quite complicated in my opinion
Thanks!
Thanks for your service 🇺🇸
I will say that this distraction became suddenly less distracting when "in 1933" lol. In all seriousness I am very grateful to be focusing on photons right now ☺️
i like this channel
I really like the shorter presentation format. My supervisor at UBC in the mid-1970s was a German who emigrated to Canada after the war-he studied at Gottingen. I learned a lot from him!
“The Nazis are the bad guys” is a pretty important point to hammer home on election night
Appreciate you and all you do. Thanks for the lovely content
I wondered that exact question just as you approached it! And my guess is that any limit to resolution would be asymptotal… that more better would continue to be better and more better still, right up to the point of diminishing returns. You know… like most things. 😊excellent vid 👍
I needed this. Thank you.
Thanks, Angela. Now I'm going to be thinking of photons for the rest of the day...
The timing of this video is beautiful. Physical Chemistry master student here and I just had a three hour class on non-linear optics. I just have a very horrible teacher that doesn’t explain the physical concepts but more the consequences of those. Would you guys have some book recommandations?
Love your videos as always
Nonlinear Optics by Robert W. Boyd
I would guess three-photon microscopy would be better overall, except that it would take a much higher power to excite smaller cross-sections of dye. There's probably a trade-off as you go up. After all, there's only so much power and attention you can give something before it starts giving diminishing returns and isn't worth the energy you spent on it. :)
19:55 "Is there a limit?!" --Angela channeling the spirit of Josh from Let's Game It Out.
Thank you! Nice take on Multiphoton processes. Franck-Hertz experiment gives me a flashback of the time when I was in Physics in University like 40 years ago... Maria Goeppert is 👍my hero! Cool Channel! Thank you, Angela! Best regards!
So cool video!
I have a tidbit to share: the same phenomenon you described in the application of microscopy is also used in laser-based lithographic nanomanufacturing to reduce the voxel size in which there is sufficient energy to excite the photoinitiator in resin!
I really want to trauma dump here but I'm just gonna say that these videos really brighten up my day
Thank you for this. Distractions are sorely needed at this moment.
Reading the german abstract, she basically said "two-photon-[emission]" (not absorption) but says "quantum" instead of "photon". So yeah assuming she'd use the same words for the absorption process, she basically said it like that :P
Thanks for the video Angela!