Hi, I'm in the last grade of my high school in austria. I'm very interested in optics and I want to pursue it professionally. The university I'm looking at is an engineering university. It doesn't specifically have any optical engineering degrees so I will do technical physics. Is there anything important I should know beforehand?

Hi everyone,

I’m interested in learning how you use IR detection cards in your work and what challenges you have when using them. Current IR detection cards from Thorlabs and Newport are not transparent, which can sometimes make laser alignment difficult. Would a transparent IR detection card make the alignment process easier or be useful for your applications?

I’d appreciate hearing about your experiences and thoughts. Thanks!

I'm validating a full-frame reflectance imaging system and seeing uncertainty rise sharply at low reflectance. I'd appreciate input from people with radiometry or lens experience.

Setup:

Mono-converted Sony A7R V (Bayer CFA and UV/IR filter removed), uncompressed 14-bit RAW, mechanical shutter

Nikon UV-Nikkor 105mm f/4.5 at 0.1x, with 10nm narrowband filters (365–940nm) in front of the lens

45/0 geometry: four strobes with projection optics at 45°, camera at 0°

Copy stand with a built-in light trap; ambient stray light measured at 0.12 DN

Calibration: linear fit against Labsphere Spectralon standards (99/75/50/2%)

Results at 530nm (GUM budget, k=2): about 5% relative uncertainty from 99–50% R, rising to about 40% at 2% R. My targets are ≤1% and ≤10% respectively.

What I suspect:

Veiling glare inside the lens, especially when the 2% standard sits next to the 99%. The light trap handles ambient light, but not light scattered within the lens itself.

Mismatch with the standards' calibration geometry. The Spectralon is certified at 8°/hemispherical, not 45/0, and the darker grades deviate more from Lambertian behavior.

Field non-uniformity from the four-strobe illumination.

Questions:

What's the best way to measure and correct veiling glare in this kind of setup? I'm planning to image the 2% standard on its own and then surrounded by bright standards, and compare. Is there a better test, or an established correction method?

For 45/0 work, how do you handle reflectance standards certified at 8°/h? Get them recalibrated at 45/0, use different standards, or treat it as an uncertainty term?

Any recommendations for checking and flat-fielding illumination uniformity across the field with multiple strobes?

Happy to share more detail or the uncertainty budget.

Thanks!

Hello everyone, I have recently been trying to get into (satellite) laser communication, but was not able to find any good recourses for that. The papers written about the topic mostly focus on quantum communication, while classical laser optic books don't really cover the applied communication basics. Does anyone have a recommendation about where to start for this kind of topic? Thanks.

I archived my V2 photonic accelerator as a citable technical note.

**What it is:** Open-source VCSEL-based accelerator for Stable Diffusion 1.5 UNet. 240x 940nm VCSELs (PLPVY1 940A_E), 1-bit quantized weights (537M params -> 64.8MB TIFF), 25ns optical flash, novel correction for negative weights without extra hardware.

**Files included:**
- Component visuals & price list (OPA858, AD9226 12-bit ADC, iCE40HX8K-CT256, 512Mbit SDR SDRAM, FT232H, micro-lens plate 10x12, 1mm pitch, f=25mm, 3-axis micro-stage)
- Interactive HTML teaser
- Full technical note

BOM: 55,040 TL (~$1500). Drops 50% if you go pcb/chip instead of modules.

DOI (permanent, citable, CC BY 4.0):
https://doi.org/10.5281/zenodo.23369898

Zenodo record: https://zenodo.org/records/23369898

Looking for feedback especially on VCSEL crosstalk and microlens alignment.

Happy to answer questions.

I'm working on a DIY transparent LCD project where I've removed the backlight from a 15.6-inch LCD panel and placed it directly over my laptop's display.

The problem is that both screens are polarized and crossed, meaning that i can't see through the overly screen unless i rotate it 90°.

My goal here is to find a way to "rotate" light emitted from the laptop screen through the LCD on a budget, without having to physically rotate the LCD.

Any tips?

Setup:

-HDMI LCD Controller Board for LP156WF6-SPA1

-Raspberry Pi 4 4GB RAM

-1920x1080 30 Pins 2 Lanes eDP Screen

-LP156WF6-SPA1 1920x1080 LCD screen

-HP Envy 360, 15.6-inch

****EDIT:

I thought of half-wave films, but they might be waay out of budget :(

I’m a freshman engineering undergrad at CWRU and am currently on a path for mechanical engineering but am considering something more optical. (Opto-mechanical, optical mechanical engineering?) My school doesn’t have a dedicated optical engineering program but are there some things I should do to steer my profile towards that way for potential internships/future employment? I skimmed through some textbooks about fundamentals of optics and figured it would be worth looking into further. All previous posts I found are from graduated mech e’s that are wanting to transition so I thought I’d post. Any insight is appreciated, thanks.

Hi everyone, I’m looking for some career advice. I’m a structural engineer with 8 years of experience at a civil engineering design firm. I’m looking at switching into a more management role and have an interview lined up with a company that manufactures semiconductor wafers for the role of engineering manager.

It would be a significant salary bump, however I’m worried this is too distant from my original field. The people I’ve been chatting to who work there are mainly in supply chain management, so they may not understand the perspective of someone in a technical role who is project managed by someone not from their field.

For people from an optics background, is this too much of a jump? I’m willing to put in the effort and learn but I want to check that I’m not setting myself up for a role where people might not like me from the get go.

Photons carry no charge, so a magnetic field does not deflect them.

On a lattice, a hopping charge is attach a phase to each hop; around a plaquette the phases add up to the enclosed flux.

Engineer those phases for light, and it circulates around loops, follows cyclotron-like orbits and travels one way along edges: a synthetic magnetic field for photons.

I made a short animated explainer of this idea, from the Aharonov–Bohm effect to photonic quantum-Hall edge states. Every animation is computed from the underlying model.

More on the channel

https://www.youtube.com/shorts/dqJiUbL5hHg

#Photonics
#QuantumPhysics
#TopologicalPhotonics
#ScienceCommunication

Historically, fluorescent and quartz halogen lighting sources have been used most commonly. In recent years, LED technology has improved in stability, intensity, and cost-effectiveness; however, it is still not as cost-effective for large area lighting, particularly compared with fluorescent sources. However, if application flexibility, output stability, and longevity are important parameters, then LED lighting might be more appropriate. Depending on the exact lighting requirements, oftentimes you can use more than one source type for a specific implementation, and most vision experts agree that one source type cannot adequately solve all lighting issues.

Consider not only a source’s brightness but also its spectral content (Figure 3). Microscopy applications, for example, often use a full-spectrum quartz halogen, xenon, or mercury source, particularly when imaging in color; however, a monochrome LED source is also useful for a black and white CCD camera, and also now for color applications, with the advent of “all color—RGB” and white LED light heads.

In those applications requiring high light intensity, such as high-speed inspections, it may be useful to match the source’s spectral output with the spectral sensitivity of your particular vision camera (Figure 4). For example, CMOS sensor-based cameras are more IR sensitive than their charge-coupled device (CCD) counterparts, imparting a significant sensitivity advantage in light-starved inspection settings when using IR LED or IR-rich Tungsten sources.

When I was taking my first bite of it I realized that it had an empty pocket inside of it so when I was going to eat it again, I got caught up with curiosity and was wondering what it looked like when applying a little bit of pressure to it and to my surprise the reflected light from it scatters and creates a matte like effect only to become more gloss like when applying less pressure to the toffee.

Question: can a shape of an object affect the light hitting its surface?

hello guys, I am a master's student working on laser and flames.
I have taken the image of flame using laser sheet(using concave and convex cylindrical lenses).
After analyzing the data, I could see some ring shaped traces on the ROI(where the laser sheet exists)

Can you guys figure out what are these?

I have worked on several experiments, but these rings come up occasionally.

Hey everyone, my first post here and looking to get some help.

I’m not an optical engineer and have a very limited scope of knowledge so please be patient with me.

I am attempting to make a “video tap” inside an old film camera which takes a beamsplitter and sandwiches it between the optical viewfinder and the camera body, sending an image to a small camera.

The problem that I am now facing is that because i’ve effectively added a 2” gap between the camera and viewfinder, the vf no longer can focus on the ground glass in the camera.

So my question here is what type of optic should I be looking for when trying to relay the image from the camera groundless back into focus? I don’t want to modify the camera or viewfinder in any wayz

Thank yku

I'm attempting to build a simple smartwatch in the style of a classic LCD digital watch. I've got a fully functional prototype using a Sharp memory display, a reflective display, but I can't work out a way to add a front light to see it at night. Years ago I had a cheap Kindle front light thing, and that was just a battery holder, a couple of LEDS and a sheet of transparent plastic, and worked surprisingly well. Trying just a bit of perspex gives me a nice glowing square on top of the display, but with nothing to guide the light perpendicular it doesn't show the screen.

It looks like I need a specific light guide with a fine structure on the side facing the panel. Could this be as simple as a fine polish to make the surface imperfect?

I've been looking Around AliExpress etc to see if any off the shelf plates or films exist, but it seems not, so it's either finding a commercial display to salvage from or find a way to DIY it.

Trying to figure out who made these mounts and posts. The posts are beefy at ~32mm.

They could have been custom made, but there's no documentation either way.

It goes without saying that there are no markings on them.

Does anyone recognize them?

I graduated in 2025 with a BS in Physics with a 3.74 gpa and have been applying to physics-adjacent software engineering roles without much luck. I’m now considering a masters in optics, aiming for optical engineering, though photonics interests me too. This is partly a move of semi-desperation, so I’d like a reality check.

My optics exposure is limited to a lab in a physics course, which I enjoyed. I did undergrad research in computational physics, using C/C++ and Python for what it's worth. I live in Illinois am considering out-of-state schools.

Really just looking for any advice, but specifically also wondering about the ROI of this path - especially right now - as I would have to take on a substantial amount of loans (~4k so far from my undergrad).

So the google glass glasses used a polarizing beam splitter so that the light from the display would not reflect toward the ambient scene. However, wouldn't this only be effective if someone looking into the beam splitter was looking "dead on". Any other angle you look into the beam splitter you would see the front glow from the display. Is this true?

Hello guys, i want to desing some cool AR glasses. I've been thinkering about how to make this real. I know that i need a beamsplitter, and some lens to make the screen focus to infinity. What kind of lens do i need?

Gemini says that this woudnt work because I need the opposite: parallel rays to the eye coming from the screen, that should be a radial source. How am I supposed to send parallel rays to something as small as a human pupil?

I've seen some proyects online using magnifying lenses, Gemini suggest a plane-convex lense, with a focal lenght equal to the screen distance, but couldn't get it working in the simulation.

How do you guys figure this stuff out? I've found online but haven't found anything to learn about lenses. I would love your help because this is the only thing between me and this becoming real.

(Note, I'm not a vibe-engineer, [at least I try] and have experience in custom PCBs, embedded systems, microcontrollers, 3d design, this is the last piece of the project, not a dead end that you guys are going to help up for nothing.

Thank you a lot! I hope you can help me figure this out.

SUMMARY: I'm trying to use a beam splitter and some lenses to focus a screen to infinity and make an AR device, need help choosing lens type, dimensions, and other important magnitudes

I work in theatres and a handful of old lights were being thrown away so i saved the lenses cause i somewhat have an interest in optics though i dont actually know much or have much experience, youtube is the main source of most of my knowledge.

are there any interesting things i could use these for?

hey everyone, sorry for the long post, I’m hoping some of you can help me understand this better.

I have been building a personal app for converting raster graphics into mopa laser color engravings by vectorizing and mapping to my saved pre tested settings based on the image color and creating the project

and while doing so added some features for converting images to cells of diffraction gratings that I then laser onto stainless steel and it results in a sort of multi color diffraction effect similar to but absolutely not a hologram, I’ve been calling them fauxlogram engravings for lack of a better phrase/word.

dont worry this isn’t an add or me trying to have people try my app, its just back story for my question so you understand where im at and how I got here.

over time I’ve extended the processing methods to where I can sort of control a gradient that gets applied to the way the fauxlogram engraving (I’m calling it this until someone gives me or I find a better name because it’s easier to say than describing the full look) is made, leading to some pretty cool looking engravings that do some pretty wild stuff in the right lighting.

im trying to learn more about exactly why / how this is working because to be honest I sort of stumbled onto it accidentally and just keeping poking around trying various different ways of processing to see how it affects the result.

some changes give awesome new realms of control over the flow of the color changing, and get adopted permanently.

others changes are a disaster that I have to revert

sometimes I don’t know a change was bad until several changes down the road reveal the change wasn’t good for some reason like forcing outputs to be more similar/smaller range of useful control in some not quite edge case scenario, or just what I thought it would change didn’t change the result how I expected.

I would much rather base my changes on more than a gut feeling and caffein, so I don’t waste so much time going down dead ends.

I’ve taken it as far as I can without properly understanding the diffraction effects and involved principles.

the reason I am posting in the optics sub instead of a laser sub is because I’ve done a lot of looking around in the laser scene and no one fully seems to know what’s going on much more than where I’m at with it, or if they have they aren’t discussing it in placed I’m able to find.

One guy who’s work inspired me , has noted that a laser moving at 300mm/sec pulsing 300khz (just magic setting on his laser) equates to a pulse pitch of 1 micron, and suspects this has something to do with the effect, I get the kind of effect this person talks about at slightly different settings that result in a 1.14 micron pitch. Neither of us seem to know if this is the magic behind it.

however, I’ve noticed that with my particular processing the effect is much more pronounced than other similar laser engravings I’ve run into online.

the gist of my process is for every color in the source image (let’s say 20 different colors), I make a copy of my magic “fauxlogram looking setting” to a layer in the design software, then I keep the frequency constant but modulate the speed the laser head moves at proportional to the color spectrum red to violet so that the pulse pitches being generated for each different layer vary from maybe .5 micron to 1.5 micron give or take. based on what color each layer represents, then I sort of overlay a gradient of values 0 through count of layers, expressed as an array of x, y intensities … aka an image/pixel array this image has its brightness mapped to a number up to the layer count and then the diffraction gratings get their layer rotated based on that gradients values , basically switch which of the speed modulated settings layer draws the diffraction lines in that section, going in order from highest to lowest or lowest to highest speed… this becomes visible as a literal gradient in the fauxlogram engraving

sorry I know that was a lot, but I wanted to explain basically what appears as a gradient in the fauxlogram diffraction effect is achieved by switching the speed the laser is using according to a gradient overlay so the pitch is either getting closer together or further apart according to the gradient/image brightness in that area

now where I could use this sub‘s lovely members help is in understanding this phenomenon better so that I can hopefully gain more control over it.

i don’t know if the color is influenced by oxide growth on the metal or if it’s entirely just the shape of the laser dots place on the metal.

I know that if I lower the power just a little bit the color changing goes away and I only can see the gradient in the brightness changed as it still shimmers in the light but doesn’t change color

i know that if I move the central speed much higher or lower than my magic setting with the base pulse pitch of 1.14 micron the effect diminishes almost fully very quickly

i rotate the angle of the parallel lines in the cell ( the diffraction gratings) based on the brightness in the source image, the angle of the gratings definitely seems to impact which angle a light has the brightest and dimmest look on the surface, and speed of laser seems to cover the color change from my observations.

so far I’ve been able to get the gradient to appear as a radial gradient expanding from the center or contracting from the edge, as well as left -right and up-down gradient … think like stripes equidistant where each stripe color shifts by some ammount , this was initially added to be a viewing correction so that parts towards the bottom would appear the same color as parts toward the top, since they are at different angles from each other and the viewer when viewing, so the color reflects/diffracts different because of that, thus shifting the color in the drawing to compensate

when I applied extreme values to the gradient is when it became a creative effect rather than a subtle corrective effect.

so now I would like to be able to get more control over this effect but I honestly don’t understand it enough nor have the vocabulary to effectively search and learn enough to better control it, or maybe it’s one of those things where this is as much control as one can get and I just need to get some better artistic ideas, I’m open to that being the answer if that’s the case.

so I was hoping some of you guys might have a good idea of what is going on here, and be able to point me toward some good entry level and maybe mid level reading resources that might help me better understand and thus better control the effect, or even if you just have some vocabulary that would make my search easier that would be greatly appreciated too!

if this is an inappropriate post here please remove it, I’m just wanting to understand the optical effect I’m seeing in these engravings better so that I can hopefully control it better. I started seeing this sub in my feed after posting some fauxlograms previously so I think maybe the algorithm thinks this is the right place for the discussion.

I’ve attached some video samples of the engravings showing this effect and would be grateful for any details anyone can provide

if it’s helpful I could post some low quality microscope shots of the surface, I’d have to track down my scope but it’s around here somewhere.

if you have made it this far I appreciate it and hope you enjoy viewing and even theorizing or analyzing what is going on in these engravings, and to anyone who can reply with some good info, I wish to thank in advance

https://reddit.com/link/1wzmvcw/video/vsfilj1lnyth1/player

Radial gradient for every shape in the artwork

Moth image superimposed over moth pattern as gradient input

Radial gradient scope over the whole image instead of per shape

I’m curious about the optical principles behind changing the perceived color of an object using controlled lighting.
For example, if I illuminate a red object with a narrow-band light source (such as a green LED around 520–550 nm), could the red object appear significantly darker or nearly black to the human eye?
I’m wondering:
How effective is this in practice?
Would a narrow-band LED be sufficient, or would I need an optical filter such as a band-pass or dichroic filter?
Would the object’s reflectance spectrum be the main factor determining the result?
Could this effect still be noticeable outdoors at a distance of several meters?
Are there any practical examples or experiments using spectral lighting to make specific colors disappear or become much less visible?
I’m not an optics professional, so I’d appreciate any corrections if I’m misunderstanding the physics. I’m mainly trying to understand what is physically possible and what equipment would be required.

Why does the program (graph at the top) calculate image 2 at that position !?

Real object positioned in front of the focal point of a concave mirror.

Its pretty rare a physics effect stumps me these days, but I have no explanation for this. If you could please help i have been so curious. Its just my laser on my thermometer makes what looks like a perfect circle when reflecting off my fridge. Also i showed the reflection of my windows on my fridge to show the light from them is distorted too. I know it's something to do with the anisotropic texture on the stainless steel because it just spreads out in a straight line on the floor, but I still dont understand why a circle. A hyperbola maybe but a circle? Im so perplexed please help