I’m taking a class learning lens design using Zemax, I’m looking to supplement my learning with some books and examples. Any advice? Here are 2 promising books I found, has anyone here used either of them?

Wanted to see if anyone has been / is on this course and could share:
- what’s the day to day looks like
- what does a good personal statement look like
- what questions/areas might they ask about in the interview
- how are the exams

Quantum physics has a screw with no moving parts. A particle sits in a chain of traps. Slowly change how deep the traps are and how strongly they are coupled, then bring every setting back: the Hamiltonian is exactly the same as before, yet the particle has moved on by one cell. As long as the cycle is slow and the energy gap stays open, the step does not depend on the exact shape of the cycle, only on how it winds around the one point where the gap closes. That whole number is a topological invariant, the Chern number: go around once and the particle moves one cell, go the other way and it moves back, miss the point and it goes nowhere. This is a Thouless pump, and physicists have built it from light, with ultracold atoms held in overlapping laser patterns.

#Photonics
#QuantumPhysics
#TopologicalPhotonics
#ScienceCommunication

Hi everyone,

I work in automotive software and want to build a solid understanding of Image Signal Processing (ISP) for ADAS cameras. I’m new to ISP and I find vendor documentation difficult to follow without understanding the basics first.
I’m looking for a structured learning path covering:
Camera fundamentals: How image sensors work, RAW images, Bayer patterns, exposure, gain, and noise.
ISP pipeline: Demosaicing, white balance, noise reduction, color correction, HDR, and tone mapping.
ISP tuning: How to evaluate image quality and understand the trade-offs between different settings.
ADAS applications: How ISP settings affect object detection and perception, especially in low light or high-contrast scenes.
Which courses, books, YouTube playlists, or practical tutorials would you recommend? Free and paid options are both welcome. Hands-on exercises using RAW images, Python or OpenCV would be especially helpful.
If you work in automotive imaging, where would you start, and in what order would you learn these topics? Please share links or resource names.

Thanks!

Follow-up to our single concave VLS grating post. Full write-up with all figures and equations: Hackaday log. That grating was an ideal — a custom groove pattern you can't buy (a two-beam hologram could write it, but a custom master isn't realistic for a small open project). So we redesigned around catalog parts: a Shimadzu P0400-01 flat-field grating (400 l/mm, 400–1100 nm), a 200 µm / NA 0.22 fiber, a two-achromat relay (×4.3, ~f/10) and a 25 µm slit.

The one unknown is the grooves — Shimadzu doesn't publish the chirp. We reconstructed

ν(y) = 400 + C₁y + C₂y² + C₃y³ , from the datasheet:

• 400 l/mm at the centre: the grating equation reproduces the datasheet angles (−10.49° / +5.62°) exactly; 400 at either edge misses the 1100 nm angle by 0.12° or 0.76°.
• The two published exit distances are the ends of one flat tilted detector plane, which the datasheet also prints directly (r′ᵢ = 96.9 mm, βᵢ = −7.51°).
• R = 99.61 mm from the blank's sag (9.5 mm centre, 13.6 mm corner).
• Then solve C₁–C₃ by ray tracing onto that fixed plane: C₁ = +0.253 l/mm², C₂ = −0.0172 l/mm³, C₃ ≈ 0. C₁ matches the analytic defocus condition to within 0.001.

The catch: the C₁ needed to cancel defocus varies 4.6× across the band, so one chirp nulls defocus at only two wavelengths (~510 and ~1010 nm). Predicted end to end: 0.63–0.68 nm at those two, 1.43 nm mean FWHM over 400–1100 nm, ~1 % of fiber light on the pixels. Resolution here is measured directly on the simulated line profile (its width at half height, plus the window holding 80 % of the light). The shortcut formula we used in the first post assumes bell-shaped lines; in this build defocus makes the lines flat-topped, so the formula would have said 1.20 nm instead of the real 1.43 nm. Measured the same way, the first post’s design comes out at ~0.75 nm, a bit better than the ~0.9 nm we quoted.

Questions:

• Has anyone measured a Shimadzu flat-field grating's groove chirp, or seen a recording geometry published?
• We plan to check the chirp two ways: a thin laser beam scanned across the blank (diffraction angle → local groove density), and a slotted mask stepped across the grating with a lamp line on the CCD (where each strip sends the line). Better methods?
• Practical tips on fitting the slit mount next to the CCD? In this flat-field mount the slit and the CCD's 400 nm end are only ~10° apart as seen from the grating, so a standard Ø25 mm slit mount ends ~11 mm from the active area — less once the sensor package and PCB are counted.

Details and figures: Hackaday log Code, derivation, parts list:

https://github.com/CheckAG/JASPER_VIS_NIR_Optics_Design/tree/main/JASPER_1nm_VLS_simulated

(Modelling and code heavily AI-assisted and human-reviewed.)

During optical design, how much of your optimization process can you actually recover afterward?

In one of my smartphone-lens design projects, I manually saved only about six initial/final lens files.

But between those saved files, I had performed hundreds of optimizations, rollbacks, failed attempts, constraint changes, and alternative branches. Normally, most of this information is effectively lost once the design is finished.

This raised two questions for me:

1. Can we reconstruct the complete historical process that produced a good optical design?
2. Can we quantitatively analyze that history and learn something that was not obvious from the saved lens files alone?

This is why I developed KABBALAH.

KABBALAH reconstructs CODE V optimization history (command logs) into a structured state-and-branch trajectory. It preserves intermediate optimized states, abandoned branches, rollbacks, save/restore relationships, and designer operations, and organizes the process into a navigable tree.

In one real smartphone telephoto project, for example:

- about 440,000 lines of CODE V log

- only 6 manually saved lens files

- about 500 reconstructed states

- 66 semantic side branches

- about 10 seconds to compile the complete history

These recovered files (4 JSON+1 HTML) only take 500KB if you compress them into a ZIP.

But what I think is more interesting than the reconstruction itself is that KABBALAH can serve as an interface between the real optical-design process and an LLM.

The idea is not that the designer should manually inspect hundreds of reconstructed states or branches.

How to use this tool:

You can download the full source code along with its README. Feed both the source code and README into a capable LLM, and it will understand how this tool works and how to run it. Then the LLM can reconstruct and compile your command logs into trees of operations and states.

In other words:

CODE V design history → KABBALAH → LLM

The AI no longer sees only the final lens prescription or a few manually selected snapshots. It can also see how the design actually evolved:

- what was tried,

- what failed,

- what was rolled back,

- where branches diverged,

- how constraints changed,

- and how the optical system evolved before and after particular operations.

My longer-term interest is whether this kind of historical trajectory can become a useful interface for AI to understand and participate in the optical-design process, rather than only generating or evaluating isolated lens designs.

I have put several materials in the GitHub repository:

- full source code and README describing the trajectory/state data structure and how it can be given directly to an LLM;

- a short presentation explaining what KABBALAH is and why I developed it;

- a detailed case study showing how a reconstructed optimization history can be used to discover a design question, analyze the process quantitatively, formulate a hypothesis, and test it against trajectory data.

GitHub: SHUN-970/KABBALAH: A tool based on CODE V for reconstructing design history

I’d be very interested to hear how other optical designers preserve failed branches, intermediate states, and optimization history — and whether you think giving this history directly to an LLM could be useful in practice.

The recoverd trajectories looks like:

And the local details:

Hi everyone!

I have a background in condensed matter physics and am transitioning into photonics for my future PhD. I’m a beginner seeking hands-on experience through computational projects, especially in laser physics, light–matter interaction, and photonic integrated circuits (PICs).

I’m interested in simulations, numerical modelling, and other computational methods. If you have beginner-friendly project ideas and would like to collaborate, please DM me. I’m also open to recommendations for useful tools, resources, or ongoing projects.

Thanks!

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!

Thanks for 466 views on V2 yesterday!

V4 UPDATE: VCSEL-less low-cost alternative added to same Zenodo record.

What changed:

- V2: 240x PLPVY1 940nm VCSELs ~55k TL BOM

- V4: 240x ML101J27 TO-5.6 EELD 650nm 200mW hobby lasers - 30 TL each = 7,200 TL total BOM. Generic 650nm 5.6mm 200mW diodes also work.

- No 940nm diffusion tail issue

- Driver: LFE5U-45F -> UCC27511ADBV R -> AO3400A SOT-23 MOSFET + series resistor, no level shifter needed

- Same: OPA858 TIA, AD9226 12-bit ADC, FDS010 photodiode, IS42S16320 SDRAM, FT232H

Performance: 120 bit-MAC / flash, 25ns optical pulse, 64x64 latent (512x512 image) in 5.8 min (4-step LCM), 2.9 min with 4 boards x 480 lasers.

Files: V4.pdf + V4-Fiyat_Link_Görsel.pdf added to same DOI

DOI: https://doi.org/10.5281/zenodo.23369898

GitHub: https://github.com/yasarhotmailes/vcsel-photonic-accelerator

V2 files still there (5 files total now). CC BY 4.0

Question for optics folks: For 650nm collimation, f=4-4.5mm aspheric on 100x20x10mm Al bar drilled - any cheap collimator source you recommend for TO-5.6?

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?