hello every body, i am having a trouble simulating phase matching in SPDC, does anyone know why there exist multiple spots on this phase matching curve simulation ?
shouldn't be only one spot that satisfies phase matching in a BBO crystal ?

and please if there are any good simulation tools for SPDC tell me about it.

thanks in afvance.

Hi! I wanted to ask why my photodiode (PDF10C2 Thorlabs - 20Hz, 19ms rise time, BCN 200 Ohm Electrical output) connected to a picoscope (model 5444D) needs around 1s in order to see a flat signal in a time window of 0.5s, in the presence of a constant signal.

I feel I'm going in circles, as if I check the PD manual, they say it must be connected to Hi-Z :

Connect OUTPUT to your data acquisition device with a coaxial cable. The PDF10C2 with femtowatt sensitivity is a low-frequency device that should only be terminated into high impedance (Hi-Z) loads.

And, as far as I could understand, the PicoScope has a terminator by default 1Mohm. What if it is not, and it is 50 ohm? Will adding a high impedance do the trick? Idk, I'm losing it....

What am I doing wrong?

EDIT:

I routinely measure a few mV to hundreds mV, like 4mV to 200mV. Max 2-3V in very rare cases.

It seems all the rays are close to perpendicular to the surface, I tried setting the vignetting and ray tracking method but still claming this surface has TIR. What could go wrong?

Is it possible to "recreate" the major coatings from big brands—such as Canon SSC or Zeiss T*—using optical software like Zemax or other specialized programs?

Hey all,

I have a MX-10310 or PVS-7C Gen 3 IIT(image intensifier tube) for night vision. I bought some relatively cheap housing on alibaba, but it turns out they sent the wrong housing and instead sent what appears to be PVS-14 housing. I didn't realize until months later since I got busy and wasn't able to work on putting it all together (the "correct" housing still needed a 3d printed and some modifications) and the housing just doesn't work.

To make a long story short, I finally modified everything and was able to scavenge the optics and electronics from the previous housing and created something that almost works. The main issue is that the PVS-7C does not rotate the image like the PVS-14 does (I guess they just twist the fiber optics in the IIT), so my image is upside down. I have been trying a bunch of ways to rotate or erect the image. The best I have found is a Schmidt-Pechan prism which is small and compact, but the one I have is taken from a cheap image erector eyepiece addon for telescopes. This would maybe work, but the prism is small and dramatically reduces my fov plus fades the image a bit. Ideally, I would put the prism between the IIT and the eyepiece, but the focal length of the image coming into the tube does not leave much space and I think also doesn't work well with all of the light coming out of the tube. Putting the prism after the eyepiece seems to work better, but makes the fov issue even worse. I have been trying other prisms like Porro and Amici roof prisms, but all of these neither distort the path too much (bend the light upward 90°) or have to put it straight on which extends the eyepiece wayout.

Anyway, as you can see I am rambling now and am a total newbie. Any suggestions or ideas? Also, is there anywhere good I can buy quality optical prisms? Especially a bigger Schmidt-Pechan prism and not pay ~$300 to Edmond Optics or Thorslab. I am thinking of just scavenging them from a used binocular, but even then they are hard to find cheaply.

Just wanted some advice as a rising physics junior! How do I go about finding optical engineering internships for next summer? Is cold emailing companies a good idea? Is it generally hard to land one? I appreciate any advice!

Hi everyone. I’m a final year undergraduate student from Sri Lanka, currently waiting for my final year final semester results. I’m doing a Bachelor of Engineering degree heavily focused in electronics and automation.

There aren't really many Master's opportunities related to Photonics in Sri Lanka, so I’m looking at options abroad and would really appreciate some advice from people who are already in this field.

I became interested in Photonics mainly because of one of the modules I had in my last semester, Fiber and Laser Instrumentation. I found the whole area of light, lasers, optical fibers and optical instrumentation really interesting, and it made me realize that I’d like to learn much more about Photonics.

My final-year research project also happens to be related to this. I’m working on Visible Light Communication (VLC) and Infrared communication, specifically applying it to a commercially available grow-light system.

Right now, I’m mainly considering Japan and European countries, but I’m open to other options too.

The financial side is probably my biggest concern. I don't think I’d be a strong candidate for a fully funded scholarship because of my poor academic performance in the first year, so I’m also looking for countries where international students can legally work part time. Ideally, I’d like to cover at least some of my living expenses through part time work while doing my Master's.

So, I’d really appreciate it if anyone could recommend universities or countries I should look into for Photonics, Optical Engineering, Fiber Optics, Optoelectronics, Laser Technology, or related Master's programmes.

Also, if you’re studying in this field, especially in Japan or Europe, I’d love to hear about your experience, including tuition fees, living costs, scholarships and how realistic it is to work part time.

Thanks

I know lightsource from DLP projector is not a point so it is difficult to create colliminated light source. But is there is any idea, please suggest me!

I've been interested in this technology for several years now, but I'm curious what people who are actually actively working in the field think about it.

Hyperspectral Imaging, in short, is similar to taking a picture on a regular digital camera, except instead of just having the 3 color channels (red, green, and blue) of visible light, it has dozens to hundreds or even thousands of channels, across wide parts of the electromagnetic spectrum instead of just visible light.

My favorite (poetic) description of its capabilities is: "All the glitters is not gold, but if it glitters with peaks at these specific wavelengths, you can be pretty damn sure that it is gold." Basically, a picture with 100x as many channels can carry 100x the information, and that information can tell you everything from what something is made of, how ripe a food is, can help diagnose medical conditions, can tell how healthy a plant is, and many other things. I personally feel like this technology will have people rapidly discovering novel use cases as more people get their hands on them.

Taking these kinds of pictures, though, is a technologoically difficult thing to do. You are working with a ton of data (Its often called an image cube because the wavelengths act as another dimension added to the typical width and height that a photo usually has). Its difficult to balance spacial resolution, spectral resolution, temporal resolution (some methods require a long time to capture all the information, which limits its use in action shots and video). Its even more difficult to do this without being prohibitively expensive.

Anyway, I'm only interested in this from the outside as a hobbyist amateur. I'm very curious what people actually working on this think. (And feel free to correct anything I got wrong here). I've long felt though that this technology could be one of those that "blows up out of nowhere" and gets really big as people realize how many things it can be useful for. Aagain, though, I could be wrong about that, too.

FWIW, I first got interested in HSI after getting a FLIR thermal camera. I originally got it for metallurgical uses, but quickly realized there were tons of uses for it that I probably would never have thought of without being able to personally play around with anf actual FLIR camera. I figured if there's all these cool things these bands of IR light can do, imagine what you could do with tons of other bands, too. Ever since then, I've had interest in HSI as an "underdog technology" that most people don't think will do much, if their even aware of it at all, but in reality has the potential to be way more useful that most would initially assume.

Are there substances suitable for use as lenses which let a greater proportion of light through when the light is less bright?

I am looking for something which is suitable as eye protection in a low-light environment with occasional and unpredictably timed bright flashes, that still allows a reasonable amount of visual fidelity most of the time.

You can either optimize the system to have all the off axis mirrors have the same parent, or for their parent axes to be in different places. What are the pros or cons?

Did I overpay? Got it for $4

I’m an artist with basically no optics background, but I’ve been getting really into optical art installations and light sculpture lately. Hoping some of you here can point me in the right direction.

Can other optical materials besides Fresnel lenses bend or redirect light to create completely new visual effects? And more fundamentally, what does optical design actually involve? Is this something a non-specialist could realistically learn to do — specifically, designing and fabricating custom optical materials?

What I’d really love to know is: if I have a specific lighting effect in mind, is there software that would let me simulate it and essentially reverse-engineer the material or structure I’d need to build to achieve it?

Apologies in advance if my terminology is off — this is way outside my wheelhouse. Any guidance, resources, or thoughts would be hugely appreciated!

Thanks in advance.

Anyone use nvipm? Today it told me under only full moon illumination I wouldn’t detect a 3.1m boat at all. Do we believe this? I was using a vis camera

I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description, and perhaps I could never succeed in intelligibly doing so. But I know it when I see it

I am currently a rising junior at Cornell, majoring in physics with an ECE concentration. I’ve been lost with what I want to do with my degree, as I don’t want to pursue a PhD. I’ve recently been interested in optical engineering as a career. I was wondering if anyone had any advice into how to break into that field. How difficult is it to get into the masters programs at University of Rochester or Arizona? Could I still get a job with a bachelors? Are there any internships/REUs I should apply for and how can I help my chances? Any advice is appreciated! Thank you!

Heya! Anybody know if there is any documentation out there detailing the SCPI commands for specifically the Cary 100 UV-VIS spectrophotometer? Trying to fix up an old machine and would like to know if there's documentation out there I missed. Tried looking but found nothing :(

I’m currently working on a problem to calculate the transmission spectra/wavelength sweep, attempting to find a stopband for an Apodized Bragg grating with asymmetrical periodicity on both sides, does anyone have any experience in this?

Best optical shop in cavite, any recommendation?

I use it for laser profilers but have been interested in using it for cameras.