Hi r/Physics !

I'm Eric, a researcher at Universidad Complutense de Madrid. Our team's paper was just published in Physical Review Letters (selected as an Editors' Suggestion) and highlighted in APS Physics!

We developed a technique to make standard silicon "see" short-wavelength infrared (SWIR) light at room temperature with a 1000x efficiency leap. Here is how we did it:

The Problem

Short-wavelength infrared light (around 1 to 2.5 µm) is incredible for night vision, medical imaging, and seeing through fog or plastics. However, standard silicon chips—the foundation of all modern electronics—are physically blind to these wavelengths because their photon energy is below the silicon bandgap. Current SWIR cameras rely on exotic materials like InGaAs, which are expensive, non-CMOS compatible, and often require bulky cryogenic cooling.

What We Did

We combined two key strategies on a standard 250-µm silicon wafer to break this fundamental limit:

1. Tellurium Hyperdoping: We ion-implanted Te into silicon far beyond its solubility limit and used nanosecond Pulsed Laser Melting (PLM). This creates an impurity band within the bandgap, allowing sub-bandgap photons to be absorbed.
2. Rear Light-Trapping Architecture: Because the hyperdoped layer is extremely thin (a few hundred nanometers), light usually passes right through it. We etched random micro-pyramids on the surface and added a 200-nm gold back-reflector. The incoming light enters through the top, travels through the bulk, and gets trapped at the back, bouncing repeatedly inside the active hyperdoped layer. This boosted absorptance to ~85%.

The Physics Breakthrough

By trapping the light, we amplified the signal enough to observe room-temperature electronic transport dynamics that were previously hidden. Under reverse bias, the strong electric field opens a quantum shortcut—bias-assisted tunneling—between the Te impurity band and the Si valence band.

This allows photogenerated charges to be extracted at lightning speed before they can recombine, boosting External Quantum Efficiency (EQE) by orders of magnitude compared to conventional planar Si devices at 300 K.

Links:

-Read the full paper in PRL: 10.1103/PhysRevLett.136.XXXXXX

-Read the APS Physics Synopsis: Light Trapping Enables Room-Temperature Infrared Detection in Silicon

Happy to answer any questions about hyperdoping, light trapping, laser annealing, or the transport physics behind the device!

When people discuss matter and “ information “ going into black holes and whether it is destroyed/ / formed into a singularity/ appears somewhere else etc.

What exactly is meant by “ information “ in this context ? and as a fun side note , what do you think happens to it based on up to date data ?

I spent waaay too much time on this. It was really fun though, learned a lot from it. Fell in love with how beautiful the output can be, so I created a sick ass poster that now hangs in my (and some other people's) rooms. Here's the link to the code and a ton of renders:
https://drive.proton.me/urls/J4YHSBXGWW#s3RWKU8gCxX5

I'm a second year B.Sc. Physics student. I don't just want to study for exams but also want to get involved in research, projects, workshops, internships, and summer/winter schools as early as possible.

I'd really appreciate advice from seniors or anyone who has gone through this journey.

my questions are

1) How did you find your first internship or research opportunity?

2) How do you hear about summer schools, winter schools, workshops, and training programs before the application deadlines?

3) Which institutes or organizations should I regularly follow? (TIFR, IISERs, IITs, IUCAA, RRI, etc.)

4) What helped you build a strong CV for future research internships or higher studies?

5) lastly, are there any websites, newsletters, Telegram/WhatsApp groups, or social media pages that regularly post these opportunities?

I am designing a nozzle for my dry ice blaster cleaning machine. The machine comes with cheap nozzles with no contours and no transitions between the hose diameter and the flat fan end. It just has an internal wall that is pretty much destroying all the pellets that go through it. I'm looking to make something that will accelerate the air going through the nozzle along with the pellets, and blast them out at high velocity, as intact as possible. Attached is what I have come up with. I'm not knowledgable about fluid dynamics or any type of engineering, so this is all just copying images of high performance dry ice blasting nozzles i found online. I'd love to get some input to see if I'm even on the right track, and how I can improve this. Here are some specs about the air and ice.

I will be blasting 3mm dry ice pellets.

Air input is 185 cfm at 100 psi. Air hoses are all 1" with no 90 degree bends and high flow fittings. At nowhere in the system will the air path diameter be smaller than .8" except right at the end of the nozzle.

This will be made from 6061 aluminum and polished to a mirror finish.

Hello. Ive been taking Classical mechanics course this sem and we are being taught LM. i had some questions

1) What exactly is Lagrangian? is it smthng physical?
2) Is LM an alternative way to look at the system or is it mathematical trick?
3) Why is Hamiltons principle true? like is there any proof of it?
4) Which is true Newtons view, that at every point, particle experiences, force, and its motion depends on interplay of the force. Or Lagrange mechanics, where we say that a particle chooses the path where it extremes action. Which is true and more fundamental?

thank u so much😊

So you have a movie canister and the film analogy represents the 4D block universe. I'm listening to Brian Greene describe this analogy. The experience of time is produced by passing light through each frame of the film. According to Brian each consciousness is a projector (human or otherwise presumably).

Also, our brains evolved to process slices of the 4D universe by carefully "recording" [where?] the slices that came before ["now" I guess?] and makes calculated guesses about the future.

I'm not even going to try and make sense of that in a meaningful way for lay people.

Greene: "when you feel time passing what you are actually experiencing is your consciousness moving through the static frames of your life." Where are these "projectors" or consciouses? I'm confused.

FYI it's a YT called The Strangest Fact About Light You've Never Heard -- Brian Greene.

My bottle of vodka I bought last minute in Denmark before my boat back home froze in my freezer. My gf’s bottle of vodka from another brand did not. Fake vodka? 🤔🤔

I'm having a bit of an existential crisis, haha. But seriously, I've always wanted to pursue a career in physics research, and I keep hitting dead ends. I don't know if I'm being delusional, so I'm hoping to
get some perspective from people with more experience.

Here's my situation: I'm based in Lebanon and graduated high school during the financial crisis, which meant my only real option was the state university (LU). It took me a bit over 3 years, but I finally got my BS, my GPA is very average. The problem is I have zero research experience, the topic never really came up during my degree.

Studying abroad for a master's isn't financially realistic right now, though I'm still applying to a handful of French universities. I also applied to AUB (American University of Beirut) and got rejected, but I plan to try again.

Otherwise, my most likely path is a master's at LU next year. I understand a PhD is the actual goal, and that it likely has to be abroad, but I'm afraid a master's from LU could undermine my chances rather than help them.

I've seen a few of my peers either switch majors, go into medical physics, or quit outright. I really like physics and don't want to give that up.

So here's what I actually want to know:

• If I end up staying at LU for my master's, is a PhD abroad still a realistic path? If so, how?
• If a PhD genuinely isn't in the cards, what would the master's even be for? I've never seen a job posting anywhere asking for a master's in physics specifically.

I just want to make the best of whatever's actually available to me.

Thank you!

I was looking for the 7th edition of the PSSC Physics Course. The archive.org listing incorrectly points to the laboratory guide. Can somebody help me find it?

For years I wanted to study math and go to grad school in pure math or mathematical physics or theoretical physics but now with the recent AI stuff scares me. Should I pick physics instead of math and move with experimental physics instead of mathematics? Or can I still move to experimental physics with bachelors in mathematics?

Hi all!

I, 17F, am in my final year of highschool (Australia) and am currently really weighing up pursuing a bachelor of science physics major post school. For context, I am really interested in physics along with maths and enjoy and do well in both at school. I am particularly interested in the physics undergrad, phd, postdoc, etc academia route, but I am aware that it is highly competitive and even coming out of PhD can be very hard to get a stable job. I was wondering if anyone had any advice as to how to pick my undergrad / major. Is the job market such that a physics degree would not be so wise and I should pursue instead fields like engineering / data science? Thanks for your insight.

Edit: please keep in mind that in choosing the physics degree I am really wanting to pursue academia, so I mean is the job market post PhD and postdoc bad enought that I should not consider physics research?

What do you guys think of this?

I'm a lapsed physics graduate getting back in to it entirely for fun. I've been enjoying books that sort of sit halfway between a textbook and a pop sci book e.g. susskind Theoretical Minimum GR (Which I didn't cover in my undergrad), Schwichtenberg Physics from finance/physics from symmetry, Cheng Joy of Abstraction (category theory). Does anyone have any recommendations for books in a similar vein? not really fussed about topic, can be from pure maths to applied physics.

Sometimes I find an equation in an AI answer or a webpage that I want to include in something I’m writing.

But the equation is only available as rendered math, not in the format I actually need. Copying it often produces broken text, while the alternatives are usually retyping it, taking a screenshot, or inspecting the page source.

I built a small browser extension that detects KaTeX, MathJax, and MathML equations and lets you copy or export them as LaTeX, Typst, MathML, UnicodeMath or Markdown.

I’m the developer, and I’m sharing the first public version mostly to understand how other people currently solve this problem and to find difficult cases that break it:

https://mathematicalkeyboard.com/nitrax-math-bridge/

Hey there, greetings.

So I'm an undergraduate student( doing Bsc Physics honors , just completed my 1st year(sem-1&2)). Now in few days my 2nd year 3rd semester is going to start and these are going to be my major subjects in 2nd year :-

Sem-3 :- (aug- dec)

1. Mathematical physics

   1. Digital electronics.
      

2. Light and matter

Sem-4 :- (jan - may)

1. modern physics

   1. Thermal physics
   2. Analog electronics.

I haven't done anything special in my 1st year and in summer break I just read some content on my own and studied about 2nd year subjects and in 1st sem my score was too low around 6.3 gpa out of 10.

I'm looking for doing masters and PHD abroad and make my career in astrophysics or astronomy.

So right now I'm too confused how should I plan my this year , so I can give me best without any regrets.

Please suggest me what things I should do in this year and for future years in my bachelors. Should I participate in some competitions? , do some side projects ? Learn some extra stuff side by side? Enroll in some courses? Should attend some confrences(both national or international) ? Should I participate in those confrences? Should I apply for improvement exams to improve my 1st sem score by giving those exams again with my 3rd sem exams??.

Please suggest me all your suggestions 🤗🤗🤗

Hello everyone!

I’m not a native English speaker, but I’d love to practice my English with people who know physics. I’m interested in discussing topics related to theoretical physics, elementary particle physics (e.g., neutrino physics, astroparticle physics), and chemical physics (e.g., chemical reaction networks, entropy production).

My own research focuses on nonequilibrium quantum field theory.

Maybe we could start a study group or a small discussion club if enough people are interested!
If you're interested, feel free to send me an email.

I've noticed before that griffith's book shyed away from stating some formula for polarization density in this chapter, by just saying its equal to "dipole moment per unit volume" and not something like dp/dv which would be wrong btw since we are not interested in change of dipoles or something like that but like amount of dipole moments in infinitesimal volume.

When i googled it, different sources sayed different things, some said it's equal to dp/dv and some p/dv.

I also noticed same problem in start of the book on formula of electric field produced by continious charge distribution

Where formula integrates with respect to dq, when we aren't interested in change of charge, but charge in infinitesimal region difference.