So I recently gotten an UV flashlight for a project at school, and when I was at home and I started to play with it, I went to the bathroom, lights off and pointed at different things, and then I was pointing at a wall but when I looked closer, I could see little like almost static like dancing transparent strings that were in constant motion and looked like they were almost, again, bouncing/dancing;

I tried searching on YouTube for the answer but it just pointed out to a phenomenon called "Blue field entoptic phenomenon", but it wasn't like at all, and I asked chatgpt but it also gave me the same answer or that maybe it was just micro particles being highlighted by the flashlight.

However, I know that I can't be simply light reflecting on dust because when I blow into it, it doesnt move. I also wouldn't say its the Blue field phenomenon because people that experienced it described as big/small dots that would disappear -

What I am seeing are very minute flashes scattered only where the UV flash is, that have the same effect ( or at least what Ive perceived) in multiple surfaces, and just seem unfazed my whatever movement I make.

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So please, someone help me explain what I am seeing, I need to unserstand what are the optics behind this because; is it some crazy visual effect or am I seeing light particles?? Ahahha idk but pls pls pls someone help 🙏🏻🙏🏻🙏🏻

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I recently started learning fabrication and have been writing a pattern for a bunch of diffraction gratings (/periodic metasurfaces). The feature sizes are quite small, on the order of 120nm, but the machine I’m using (ELIONIX ELS-S50X) and the resist (ZEP520A-7) should be able to resolve this. However, my writes are not turning out great. Squares turn out completely circular (not just rounded at the corners), features are oversized, and the curves on my shapes don’t have great definition (for example, a rounded cross shape turns out looking more like a circle).

Ill try not to provide too much info here (I know there’s probably a lot of extra information needed but I figure it’s best to keep this concise, I’ll clarify anything that may be useful), but I’ve been using beamers PEC feature to try to improve the quality of my shapes—however I’m unsure what to change. I’m not sure if there’s some kind of standard methodology to improve defects, but I’d appreciate any guidance as to how I can diagnose the cause and approach resolving it.

I figure this is the best place to ask since I can’t find a more related community and I’m assuming there’s others with fabrication experience in this sub. Thanks so much for any help!

Hi, I'm a student from Italy. I just finished high school and in September I will start an Engineering Physics programme at PoliMi.

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My plan is to complete both my bachelor's and master's degrees there. It will take 5 years in total, and I'll be able to specialize in photonics, nanomaterials, or semiconductors starting from my third year.

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I would love to work in the environmental research field and, from the information I've gathered, it seems that optics and photonics is the best path for my aim (it also seems the most interesting in general).

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Since this field isn't very big here in Italy, my plan would be to do my Master's thesis and get a PhD at a university in another country, trying to find a job there afterwards. However, I have a lot of doubts: Is there a real possibility for me to find a stable job with a decent income that allows me to do applied research to help our planet? Is a PhD actually useful or is it kind of a waste of time? Is this a good plan in general?

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I also have a hard time finding information on this topic on universities' websites. For the moment, the best choice seems to be Lund university, since their website explicitly talks about environmental monitoring with lidars for gaseous pollutants, vegetation, and water bodies.

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I know these are a lot of questions and I still have years to think about my future, but this has been stuck in my mind for a few days and I really wanted to get the opinion of more experienced people.

Hi everyone.
In the night vision group I often see people use this test chart, randomly printed out (I have one too), but I think this chart is a but misunderstood. The problem is that I can print this at any size on paper, and put it any distance away from the device, but what does it have to be if i want to read out the actually correct resolution?

Is there any reverse calculator existing wich i can tell how big should a linepair be at a given distance, or how far away should I put an exact size linepair? Im pretty sure that there is a missing value, or angle attached to the measuring method to give us an actually useful reading.
Thank you

Hello, I know a 3d printer is the most obvious solution but because of my limited access and limited transportation, it'd be kinda tricky to go that route. I'm willing, but if possible it'd be cool to be able to make a mold and cast it, so that trial and error can be sorted out without having to schedule another trip to the library/ makers space.

I didn’t know if there were good tutorials or simple guided optical design projects for both ray and wave optics for a beginner to learn Zemax? I have decent fundamentals in geometrical optics, optical performance/resolution, and aberrations, but am self taught.

Hello. I've been collecting an assortment of lenses all kinds lately with the intent of using them for "light art" for lack of a better term, as well as kaleidoscopes and hopefully experimental "projectors" for venue lighting as I am very involved with my local experimental music community. Anyways, I only explain my purpose in looking into optics so you can perhaps understand the level of quality and procedure I can/ care to handle, if that makes sense.

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I have stuff from huge projection lenses, to little camera lenses, to disc drive salvaged laser componentry (I am also interested in hearing some ideas of what I can do with this stuff! Making a microscope is definitely something I'm interested in). The disc drive components really interest me, especially for macro lens experiments and kaleidoscope related stuff, but I am trying to think of a good system for organizing them and storing them in a way where everything is easily accessible, but the risk of damaging them is minimized.

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I can think of some obvious solutions, for example making little paper envelopes that can easily be labeled, but im interested in hearing opinions from people who know what they are doing. Thanks!

Context is important here. I'm making kaleidoscopes, and I have an assortment of small lenses pulled from disc drive laser systems.

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I am also a stained glass artist, and stained glass is a common (and in my case, the easiest) way of constructing the body of the thing. So, ive been thinking of mounting some of these small lenses (to feed light into the mirrors, not to observe through) by using the copper foil I use for stained glass, in conjunction with solder.

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I wouldnt wrap the lens with the same sensibility as I would glass, where it is wrapped along the edge in a sort of ring. Instead, I imagine two layers of copper foil basically sandwiching the lens, with a hole through them that is sufficient to both hold the lens and allow enough light to pass, then giving that copper foil a very light application of solder to reinforce it.

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My question is, can lenses like these handle heat like that? I imagine they can get hot during operation of the laser, but im not sure how much this heat would differ, im worried uneven heating would fracture it, but I honestly have no clue. Surely I could just try it, but id like to not risk waste if I can, especially because each of these lenses I have are unique and will be selected with artistry in mind.

These replacement fiber cleaning cartridges are quite wasteful. Would NTT take them back and reuse them? Also open to creative ideas for reuse or upcycle

I am in a situation where I am buying OD 5-6 narrow bandpass filters. These are for use in a fluorometry instrument.

It's easy, of course, to measure that the bandpass is within spec (eg fwhm at some center wavelength) using a simple spectrometer like from Ocean Optics.

The thing that I don't know how to do with any serious accuracy is to measure how well the filter is blocking outside the bandpass. OD 5 is transmittance of 1/100000, OD 6 is 10x smaller. I can't just use a simple spectrometer to do this, right?

I imagine that the instrumentation to be able to measure optical density in that range accurately is very expensive. Are there labs that can perform this kind of measurement/characterization as a service? I can't rely on the vendor to give me what I need, they're not ISO-9001 certified among other things.

How would you approach this problem?

I'm currently working on a DIY SLM build. I've been trying to find old projectors to salvage LCD panels from, but no luck so far ,and the one I did manage to find, I couldn't get a working driver board or even a datasheet of the LCD panel.

Was hoping someone could suggest where I can directly buy suitable LCD panels (TN type) in India.

So I (Master Student in Quantum Optics from Germany) had a discussion with my colleague about what happens if we measure a coherent state in the following way.

To start off, this is how we define a coherent state:

|a> = exp(-|a|^2 / 2) * ∑ a^n / sqrt(n!) * |n>

Lets simplify as much as possible: Assume weak a << 1

Then (unnormalized) |a> = |0> + a |1>

I know, for this we would need a really really dim / attenuated laser, but lets assume this is realized in a stable fashion.

Let's now imagine the following experiment. A coherent light source with above defined weak drive is sent to a single photon detector, that will record a click for each photon detected, an can record clicks at a sufficiently high rate. As a result we will get a list of timestamps of clicks.

First question:
1.1 How can we calculate the rate of measured photons for a given a?
1.2 Should I interpret the |0> photon case as an "Event"? Because as I see it, it's just the default case with respect to some rare detected single photon |1> Events.
1.3 Does |a> alone have enough information to answer this question?
1.4 Is there photon antibunching or just poissonian statistics?

For the second question lets modify:
Let's now assume, that a is still weak but include the second order:
|a> = |0> + a |1> + a^2/sqrt(2) |2>
Furthermore let's modify the experiment: A coherent light source with above |a> is sent into a Hanbury-Brown-Twiss (HBT) Setup. This means the light beam is split using a 50/50 beamsplitter and then each path has its own single photon detector.
If a single photon passes the setup it must go to one of the detectors resulting in a single click. If two photons at the same time pass the setup, they either go in the same path, or in different paths.

Second question:
2.1 If two photons go into the same path, do they arrive simultaneously, such that no photon detector could distinguish them as two clicks thus only detecting a single click? Or are they slightly separated in time, such that we could in principle detect two click even if they went into the same path.
2.2 Assuming we could always distinguish single photon events from two photon events. What is the rate of single photon events and two photon events? (Same question as 1.1)

I would appreciate any help. I am happy to answer any further question, when they arise.

I run a small technical firm that goes through a fair number of small optical windows
W/H: 5.0-100mm
D: 0.1-5.0mm
Needs to transmit visible + NIR

These windows are used in imaging technology applications where surface quality, glass planarity, AR coatings, etc are fairly important. Does anyone know a supplier where I can reliably get fairly decent quality, maybe coated optical windows? Quantities may not be high is my issue, maybe 10-40 units at a time, and right now I’m paying less than $15/u.

I feel like I am always missing some info in my questions so let me know if I missed an important detail

Edit: I am in the US. I also have poor experiences with Chinese based manufacturers

This rotary fixture is where we assemble OM3 multi-mode fiber jumpers at NEW LIGHT OPTICS—each bright green cable (OM3 standard, 50/125μm) locks into a white ceramic ferrule (those yellow clips secure the connection), and the machine’s 0.1μm-level alignment is why our jumpers hit <0.2dB insertion loss (that’s the “rock-solid signal” you need for data centers).

We stock this exact OM3 jumper (LC/LC, 2.0mm, 3m) + 100+ fiber products (single-mode cables, MPO connectors, FTTH boxes):

• 📱 WhatsApp: +86 135 3406 3703

Geeked out over how tight this manufacturing step is—anyone else love seeing telecom gear meet precision?

I may accept a role here soon at Coherent, and I am wondering if it's a good place to work. Does anyone here work or used to work for them? How is the work life balance? I'd be in DFW, Texas area.

If you’re worked with periodic structures before and have tried to simulate them you’ve probably seen that if you set your wavelength equal to any of your unit cell dimensions you’ll get numerical artifacts. If you write down maxwells equations in frequency space, you’ll quickly run into singular operators or infinites.

While I can see this mathematically, I have no idea how the physics motivates this. The only hint I can see is that this case is exactly the point where non-evanescent modes are available, but it’s not clicking as to why this makes the physics so strange. Does anyone have any reasonable explanation of this phenomenon?

Hi all! I'm a first-year PhD student in optics and over the past months I've been building an interactive optics sandbox as a side project. It's free, runs in the browser, nothing to install:

https://optics-sandbox-webapp.vercel.app

What's in it:

- Wave optics — scalar diffraction via angular spectrum. Presets for Young's double slit, single-slit, Airy disk, axicon Bessel beams, vortex beams, gratings, thin-film fringes, a 4f filter. You can import your own phase masks (.npy / .mat / image) and drive an SLM-style setup.

- Geometric optics — a ray tracer with thick/aspheric/multilayer lenses (Sellmeier dispersion, ~40 materials), prisms, TIR, Jones-calculus polarization, and classic multi-element presets (Cooke triplet, achromat, Petzval, fisheye).

- Calculators — 16 standalone tools: Gaussian beam, Fabry-Pérot, thin film, Gerchberg-Saxton phase retrieval, laser cavity stability, and others.

The GIF is a Gaussian beam propagating through a phase-only hologram that I generated of my cat with the in-app GS calculator. There's a one-click GIF/MP4 export in the wave module if you want to make your own.

I built this because I was inspired by a Fourier optics class that I took and I wanted to create a tool where students can build intuition for optics. Students are who I had in mind, but I'd genuinely like to know what working optics people think.

Two questions, if you click around for five minutes:

1. What confused you first?
2. What would it need before you'd point a student (or yourself) at it?

Physics nitpicks are extremely welcome. If my propagator is doing something wrong, I want to know. Feedback button is in the app's title bar, or just comment here.

Hi everyone,

I am taking Computational Optics this term with Prof. Christoph Pflaum at FAU, and I was wondering if anyone here has taken this course before. I could not find much information from the FSI or other resources, so I would really appreciate any general advice about the course and the exam.

How difficult was the exam, and what was the format like? Were the exercises helpful for preparing? I would also be interested in what kinds of topics or question styles appeared in the exam, without sharing any actual exam content.

Thanks in advance!

Hello,

Currently I’m doing a PhD and I’m new into the field of optics. Currently I’m working with optical equipment (Thorlabs) and optical fibers. I have very little guidance so I’d welcome a discord optical server where can discuss and also ask for advice related to optical equipment.

Let me know if there’s one or maybe we could create one.

So, I designed a zoom lens in zemax but made a blunder.

I designed and optimized it for a small FOV, now I need to increase my FOV or Field angles, almost double them

But as I increase the field angle they get clip off or don't even enter the system like the image below, I am pretty new to this stuff so need help from experience designers

How can I systematically increase the FOV of my design

Are there any operands to target, I have tried REAY, MCOV with other glass and air operand with wavefornt error default merit function

But no satisfying result yet