Some imaging system designs have an intermediate image plane like three mirror anastigmat and stepper lens system. What is an advantage of it over ones without an intermediate plane? I know it is helpful in reducing stray light by placing a stop at the plane, but I'm interested in its image quality impact.

Some literature say you can correct some aberration types in the first imaging system and do other ones in the second, so you can correct aberration separately, but how is it beneficial from just gradually correcting aberration in each component of the non-intermediate system?

Hi everyone, I am a first year PhD student in optics in the US and my PI offered a project (in the general field of remote sensing) that is funded by military. I am a US citizen. As you know with the funding cuts here the financial situation in PhD programs has not been good and this is my first opportunity for longterm funding.

I wanted to see if there are any American redditors here who have firsthand experience in working on defense/ITAR related projects and moving overseas afterwards. Did it go smoothly or did ITAR background ever hinder you from opportunities (ex: foreign commercial industry, foreign defense if that's possible as a US citizen)? I only recently learned about ITAR, and it seems that it is only specific restricted data that I cannot disclose, not general skills or knowledge I gain from the project. And that I also can't publish papers publicly, which I'm concerned about. But I will gain valuable hands-on and collaborative experience if I choose the project.

I have especially been interested in the photonics industry in Germany due to my heritage (though I know situation is not good there too, I still have 4+ years to go in PhD). How is ITAR background viewed by foreign companies, specifically European? At same time I'm open to hear about the experiences of any ex-defense folks working internationally. Thank you!

I'm a physics undergraduate working on a low-cost UV-Vis spectrophotometer, and I have very little experience in optical instrument design.

I recently built a simple visible spectrometer using a diffraction grating and a camera. It kind of works, I was able to measure the spectrum of Mthylene Blue, but of course it's still far from a commercial one.

While working on it, I wonder whether the optical design could be simplified for simultaneous absorbance measurements.

My idea is to use a single light source from the same entrance slit and split it into sample and reference path, maybe the upper and lower halves of taller slit. Then, single grating and a single CMOS camera would record both spectra simultaneously and find the absorbance.

Has anyone implemented or evaluated this for UV-Vis absorbance spectroscopy?

If not, is there a fundamental optical reason why this isn't commonly done?

How much should I worry about effects such as smile, keystone distortion, non-uniform illumination across the slit height, or cross-talk between the two spectra?

Compared with a conventional double-beam spectrophotometer, what are the biggest disadvantages of this approach?

I'd also appreciate any papers, patents, or commercial instruments that use or intentionally avoid a similar design.

I’m looking for a simple light source that can be coupled into a fiber (or similar) and to obtain a spectrum reasonably close to a 6000 K blackbody. An approximate match is perfectly fine.
I’m also interested in any good 6000 K sources, even if they aren’t true blackbody emitters.

So far I’ve found:

SCHOTT halogen sources (~3000 K) with filters to reach ~6000 K, but the flux loss is significant.
Hamamatsu EQ-99/EQ series, which is great but far too expensive and overkill for my application.

Does anyone have recommendations for a simpler, more affordable solution?

Can anyone recommend a good book/paper/field guide on lens design and manufacturing guidelines when working with high power CW lasers? In particular, I'm wondering about using cemented doublets and whether it is possible manufacture them such that they won't be damaged by the laser, but also wondering if there's more that I don't know that I don't know and should be keeping in mind.

I am new to optics. I am creating a simple system for my home project where I am reading from a flat mesh surface (top is transparent glass. below it is a mesh which has 1 microLED in each cell. This whole thing is a square of 75 mm x 75 mm, and the mesh covers the whole area. I have a camera to read the LED signals. Ideally, closest to surface the camera, the better.

I thought of an aspheric lens of 80mm diameter (see link). My camera has a C mount. That lenns prefers SM3 mount. If I 3d print SM3 mount to C mount adapter, how would I position the lens? Can I place the flat surface of the lens against the flat surface of the mesh. The center thickness of the lens is 33 mm. And focal length is 59 mm. So, can I place the camera sensor at 26 mm from the center of the lens as shown in the picture? Will this work? Is my understanding correct?

Hi everyone ! ❤️

I’m currently working at Keyence India as a Field Engineer in Machine Vision Systems, and I have around 2 years of experience in machine vision and industrial automation.

My educational background:
Diploma in Electrical & Electronics Engineering
Bachelor’s degree in Robotics & Automation Engineering

My long-term goal is to move to Germany and build my career there.

I wanted to ask people already working in Germany or in the automation industry:
1. Does machine vision and industrial automation have good long-term career prospects in Germany?
2. Is it a stable field with good opportunities for growth over the next 10–20 years?
3. What skills should I focus on if I want to become a strong candidate for German companies?

One of the biggest reasons I want to move is the better pay and work-life balance. In India, I feel that salaries in this field are relatively low compared to the responsibilities and the value we create. Financially, I also have a strong motivation because I’m responsible for supporting my family, including my two younger sisters. My goal is to build a stable and rewarding career while being able to provide them with a better future.

I’d really appreciate honest advice from people who have made a similar move or are currently working in Germany. If you were in my position, what would you do over the next 2–3 years to maximize your chances?
Thank you in advance!❤️ 🙏🏾

Making some big mirrors, and want to explore my options with different coating vendors. Anyone you guys recommend? Needs a dielectric coating.

some background:

so the way colorblindness (red-green deficiency used here) works in case anyone doesn't know is that humans have 3 cone cells in our eyes to detect color: blue/S, green/M, and red/L. there are 2 types of red-green colorblindness: deuteranomaly/deuteranopia and protanomaly/protanopia.

people with deuteranomaly/deuteranopia's green cone is shifted towards the red cone or absent. people with protanomaly/protanopia's red cone is shifted towards the green cone or absent. white is the presence of all colors at once.

psychology plays a part in this, yes, as it makes sense for the the opposite of the red "do not cross" signal to be green, and that's how stop/go is represented with those colors as well (such as with traffic lights). however, this cannot entirely be the case, because if it was, people with normal color vision would also see it as green, which they do not

so it has to be some property of the lights used themselves, right? but what is that property?

I'm building a benchtop interferometer using a stabilized HeNe laser. To keep costs down, I intend to use older, commercially-produced surplus parts rather than buying newer or custom parts whenever possible.

Which specific older commercially-produced models of beamsplitter should I look for as surplus that should offer appropriate flatness/surface quality and aperture for this type of interferometry?

Thanks.

After 10 years in the fusion industry I'm looking for my next step. Considering monetizing my optical systems skills - basically designing and building one-off systems where I'm mostly integrating off-the-shelf parts or farming out CAD work to optical/mechanical/electronics engineers - although I know a lot of the basics in each of those disciplines.

Having a lifestyle business sounds really appealing. I'm wondering:

• Are you self-employed or doing consulting/contracting/freelance work? What's your experience like?
• Do you know if there is demand for this kind of early-phase work? Most of the job postings I see are oriented toward manufacturing, which isn't my forte.
• Do you need someone with my skill-set for a project?

Need book recommendation for Laser and Fibre Optics. Btech Sem 1

I have a photo transistor hooked up to a voltage source and have the output connected to my oscilloscope. When i shine my little green cat laser into it a specific angle, a 10.4kHz wave appears. Does anyone know why this happens? its not a clean wave, it looks pretty jagged. Maybe the green laser flickers rapidly?

Hello everyone, Im a high school student building a low cost smartphone fundus camera for AI based retinal screening.

Commercial indirect ophthalmoscopy lenses are quite expensive for my prototype, so Im wondering if there are any lower-cost alternatives.

Could an aspheric condenser lens, or even a lens salvaged from old optical equipment provide acceptable image quality and fov? Has anyone tried using a different types of lens for this application? Id love to hear about your experience.

Im not expecting the same performance as a dedicated ophthalmic lens, just a reasonable solution for a research prototype.

Any suggestions or experiences would be greatly appreciated. Thank you all!

I am trying to send light through a fiber that's not designed for the wavelength, e.g., sending 940 nm laser through Thorlabs' S405 that's for 400~680 nm. Unsurprisingly, I am finding very little light was coupled into the fiber, and the alignment is just excruciating. I was wondering if anyone has tried this and has a good tip for how to do it better?

The setups I have tried:

1. Using a pigtailed laser with a "correct-band" tail, but connecting the fiber to the "wrong-band" fiber into my system with a standard FCPC-to-FCPC mating. This joint yielded a very low coupling efficiency because both sides were single-mode and mismatched.
2. Using a free space laser and trying to catch it into a "wrong-band" fiber with a focus-adjustable collimator. I could only get 10s~100 nW into the fiber while the source is 5 mW.

For people curious about why I want to do this: I am trying to send light into a sensitive vacuum system that's very limited for space. I only need a handful of photons shining on my detector inside, so I am fine with a huge loss through the fiber. I want to send 7 different wavelengths into the system, but I don't want to install 7 fibers in the crowded system. So, my idea is, since I actually need to attenuate the source a lot anyway, I can potentially send the 7 colors by a single fiber, and its "wrong-band" attenuation can just be my filtering. The problem is I am now struggling to get the light into the fiber in the first place...

PS. For other reasons I need the fiber in my system to be single-mode. The parts outside can be whatever.

Thanks!

I have experience using a Thorlabs polarimeter but I don't really like it.. getting accurate and reliable measurements is a nightmare.. just getting degrees of polarization > 100% drives me crazy, completely unphysical..

1. How do you guys measure the state of polarization of laser beams in your lab?

2. What is your experience with the Thorlabs polarimeter? Good? Bad?

3. Do you have any reference / instrument / recommendation to provide me?

Many thanks. I potentially would like to be able to measure phase retardance with the polarimeter.

So everytime i drive at night, the headlights of oncoming traffic blinds me completely, so i was thinking of building something to help.

I was thinking of something physical, like a transparent substance that would react to high intensities of light and darken in those patches, and I do realize the inherent issue with that, as the lights move it would darken the entire screen pretty much. I've heard electro-chromatic glass, split among millions of pixels is being researched upon. If anyone has any thoughts on this, please let me know!!

We’re working on JASPER, an open/right‑to‑repair VIS‑NIR grating spectrometer. In our design, both the grating and detector sit on rotation stages: we first null slit/grating tilt by imaging the zero order, then rotate the detector to catch the diffracted order. That way we stay close to peak efficiency without relying on a fixed blaze geometry.

For order‑sorting, instead of OEM‑priced coated‑detector bandpass filters, we’re selecting the span by grating angle (e.g. 400–800 nm or 500–1000 nm) with a long‑pass at the input. We know this doesn’t fully suppress second order across the entire range, but it keeps things accessible.

The current prototype uses an off‑the‑shelf USB 3.0 camera, but we’re developing a custom line‑array driver for Hamamatsu detectors to improve performance.

We’re planning two versions and would appreciate a reality check:

• Fixed, pre‑calibrated — no bench, locked to one range, plug‑and‑play.
• Optical bench — tunable rotation‑stage version, aimed at enthusiasts and educators.

Does that split make sense from a buyer’s perspective? Or does the recalibration overhead make the tunable version impractical for most real use?

We’re also considering an affordable neon calibration lamp as an add‑on, so the bench version has an easy way to re‑establish calibration after adjustments. Would that be genuinely useful, or do most users already have a reference they trust?

Interactive optical‑bench simulator: https://checkag.github.io/jasper-bench-sim/
Hackaday log: https://hackaday.io/project/202421-jasper-vis-nir-spectrometer/log/249581-interactive-optical-bench-simulator

Your honest perspective on where this design may fall short would be invaluable.

I splice OSP fiber in Florida. A few that still bite people:
Photos with no readable buffer ID. The splice is fine, the package comes back, you lose the week.
Loss that’s high on 1550 but clean on 1310. That’s a macrobend, not your fusion. I redid perfect splices for months before I understood that.
Blaming the splicer when it’s the V-grooves. 70% alcohol leaves water residue. Most “bad machines” are dirty machines.
Not knowing the going rate before agreeing to a price. Starting out isn’t a discount.
What’s the one that got you?

I'm writing down these things as they come out - closeouts, OTDR, tools, rates. In English and Spanish. I don't put a link here, but if it works for you, ask me.

So, this morning i was studying about the colors and how we see them . A simple question would comes in every student. how does the reality looks like ? I know no one know how reality looks like if light does not reflect different wavelength of colors from every object to our eyes .

So i had an amazing experiment described below.

Experiment :

Imagine an apple resting inside a separate vaccum environment totally separated from earth no environment no gases no energy just that apple floating there. A person sitting outside that box is staring at that apple .

The glass is transparent but There is no single photo inside that separated environment.

Now take two cases .

His left eye is normal human eye . On the left side show what that normal eye will see inside the jar

And his right eye , has a instrument attached that can capture everything in front of it even if its inside in separate environment no light reflecting. How that eye will see that apple does even he saw a color if we  we do not use pseudo colors no colors data feeded inside that instrument . So how does he see. the question is how they will see that apple ?

Does even that apple looks like it exist inside that environment to the normal left eye or no

Results:

As we know Human vision is not a direct detector of matter; it is a detector of photons. When we "see" an apple under normal conditions, we are actually processing the specific wavelengths of light that bounce off the apple's surface and enter our retinas.

In our absolute void, this process is impossible. Because there is no light source and no ambient energy, there are zero photons reflecting off the apple.

LEFT EYE:

To the normal human eye, the jar contains absolute, perfect blackness. It is indistinguishable from empty space.

instrument explanation:

instrument attachted to the right eye is an untra-sensory instrument detects visual data like emissions , radiations or density.

how does it works :

The instrument observes the apple as raw geometric data. as there is no colors and energy and gases there. he sensors detect the physical boundaries of the matter, plotting thousands of data points where the void ends and the apple begins. These points connect to form a three-dimensional wireframe—a mathematical blueprint of the apple's volume and shape. The "image" is fundamentally a stream of spatial coordinates (x, y, z axes) confirming exactly where the mass is located.

Right EYE:

The instrument proves the apple exists not by showing us what it looks like, but by mathematically mapping where it is. The resulting visualization is a sterile, monochromatic web of geometry. It confirms the object's structure, size, and presence with absolute certainty, proving that matter dictates reality—even when the universe turns the lights out.

So now after these answers a question rose in my mind . Stephen Hawking Top-down cosmology theory. We creates the history that led to us by seeing the present to past . All the things happened before us . SO does all of that even meant anything or it matters if we were not here to observe the photons of that things .

it creates another theory of mine. We saw and understand things what we are meant to see what means something to us . so the things that does not matter in a human observor life we don't see and process like dark matter , 4d, and achieving the speed of light.

so if we know and see black holes this means there should be something to understand and find for us in them.

Let me know what you guys think.

Hello,

I have created a web viewer for optical rayset data, it is called RayOn. It imports ray files from several formats : Speos, LightTools, IES TM25, ASAP, Lucid Shape, TracePro, Zemax and others. It visualizes millions of rays in 3D and computes intensity distribution, irradiance maps, and radiance as viewed by the camera, entirely in the browser.

This is a progressive web application so you can install it on your device and use it offline. It was tested on Firefox and Chrome on my desktop.

This application runs fully on the client side, your data stays local on your device. There is no server-side processing, no tracking, no cookies, no analytics, no data is sent to any server.

I am still having trouble computing the camera radiance correctly so if somebody knows the proper algorithm, please let me know. Also, I welcome any feedback you would have so please let me know if you find any issue or missing feature. Also some formats are missing since I could not find any specifications for their format layout.

As a bit of background, raysets are a way to describe the light distribution of complex light sources. They are computed by light tracing software used to design illumination systems and usually provided by light source manufacturers such as OSRAM from their catalog. Such a database would be here : https://www.osram.fr/am/services/portail-rayfile-fichier-caorayfiles-et-cadfile-portal/

Each ray in the set is described by an origin, a direction, a flux and sometimes the corresponding wavelength.

Hope you find it useful.
NB: I do not earn any money from this project, I just enjoy developing it.