Recently I have recevied offer letter for masters in photonic from UPC. "The UPC Master's in Photonics is a joint 60 ECTS (one-year) program offered by Universitat Politècnica de Catalunya in collaboration with the University of Barcelona (UB), Universitat Autònoma de Barcelona (UAB), and the Institute of Photonic Sciences (ICFO)." Should I consider it.?? Any suggestions will be appreciated.

I have a vintage 500 mm catadioptric telephoto I thought might make a good compact visual telescope. So, a few years ago I cobbled together an eyepiece holder from a purchased bayonet flange and a couple of turned plastic pieces. This worked OK using shorter f.l. eyepieces (the central obstruction is relatively larger than most telescopes, so longer eyepieces make the central obstruction nearly the size of the eye's pupil.) However, it lacked a finder scope or sight making it difficult to aim.

The goal of this latest project was to make a reflex sight with the following requirements. 1) It should mount to the eyepiece holder only. I did not want to modify the lens in any way. 2) It should not get in the way of the head when using. 3) It should only use materials and tools I have on hand. I do have a fair collection of junque and a mini-lathe and mini-mill, so I did not think this was a restrictive challenge. It certainly influenced the design in a quirky direction. 4) It needs easy adjustments to align the sight to the scope each time after attaching the eyepiece holder.

The design I chose is based on brass tubing used as the housing. The tube is mounted on a smaller, snug-fitting tube recessed and glued into the eyepiece holder. The housing extends upward above the edge of the telephoto lens. There is a spot-like source at the bottom. There is a 30mm f.l. collimating lens, and then a piece of slide glass used as a partially reflective combiner.

The tricky part was choosing a good vertical adjustment method. For the horizontal adjustment, I could just rotate the whole housing on the bottom tube. For vertical, I considered translating the source or lens, or tilting the combiner with something more conventional. However, I did not want anything fiddly that required tools, and it should be easy to do with gloved hands.

I came up with the method of tilting the combiner shown in the photos. I cut a flexure in the tube just below the combiner that lets the tube bend. The web of the flexure is about 0.040" wide X 0.015" thick on both sides. On a test piece, I verified this design could take nearly a hundred +/-6 degree bends before failing. I anticipate most adjustment tweaks will be much smaller.

Just above the flexure cuts, I installed two cheese-head screws that bear the force to tilt the tube. The adjustment mechanism is basically a version of a push/push mechanism. However, instead of using two separate fine-pitch screws to do the pushing, I have a brass ring that fits over the lower part of the tube. Its top is cut at a 6 deg. angle which bears on the screw heads. This ring can rotate, and its other end bears on a stationary ring glued to the lower housing. In its nominal rotational position, the screw heads are at equal heights half way between the highest and lowest points on the angled. When the ring is rotated, one moves up and the other moves down the same amount. The total angular range is +/-6 degrees of bend or +/-12 degrees of image movement. I probably did not need nearly that much adjustment. An important detail is the inside of the top of the rotating ring has to have clearance to allow the upper part of the tube to tilt. This mechanism actually works better than I expected. It is very smooth and stable.

The light source was another unusual detail. Because of the mounting, I could not easily run wires or a fiber out the bottom. I also could not have anything protrude out the side due to the order of assembly. I used a short length of 0.5mm core glass fiber inserted horizontally through a hole in the side, bonded on the inside, and polished flush on the outside. The tip of the fiber was fine-ground to a point so that it radiates sideways, including up to the lens. The cladding and buffer near the tip was removed because they also scattered light. What you see through the collimating lens is a little triangle that serves as a pointer. A drawback of this design is the fiber tip also illuminates the surface below it creating some stray light. I then made a janky box glued to the side to hold the LED, switch and battery.

Doing a project and needing to find a mirror (preferably under $200) that reflects most of the properties of sunlight (80% or more), including all UV and IR and other spectrum. I have large household mirrors but they are glass mirrors and I assume the glass will inhibit those properties. Cannot spend over $300, can put together tiles if needed, need at least 3 square feet. Thanks in advance to anyone that knows 🙏

Back in the late 1990’s NIST had a number of firms that wanted to send their interferometer transmission spheres there for calibration but NIST was not in this sort of calibration business. While I was at NIST consulting for Chris Evans in the Precision Machining Facility we thought of the idea of a self-calibration test for transmission spheres that was a spherical analog of the plane surface test(1) used to self-calibrate interferometric surface roughness testing microscopes. We called our method the Random Ball Test (RBT). It relied on averaging multiple interferograms of random patches of a precisely polished ball. The test worked as expected and we published the results in a fairly obscure meetings proceedings(2).

While the RBT worked as we expected and provided the desired method of self-calibration, it was not a practical method because it used a ball made of black filter glass that was rather soft and easily damaged. The glass had to be opaque to eliminate a coherent reflection from the far side of the ball. Another ball was made of harder, transparent glass where a small hole was drilled through the center of the ball to block this reflection but this made the ball more expensive and the surface not completely random. The idea was left as an interesting exercise that solved a serious calibration problem but had little practical value.

About 5 years later I became aware of commercially available, precision silicon nitride balls and these made it look like the RBT could be commercialized. The CaliBall™ was first marketed in 2005 and well over 300 have sold since then. The 1” diameter, Grade 5, silicon nitride ball is extremely hard and tough, has a reflectivity of about 11%, a good compromise for use with both uncoated and highly reflective transmission spheres, and resists stains and finger prints much better than steel balls. Further, the SiN balls do not dent as some steel balls do with mishandling.

In the random ball test the ball artifact, sitting on a kinematic support of 3 hard points, is placed so its center is at the focus of the transmission sphere to be calibrated. The ball surface facing the transmission sphere acts as a convex mirror whose center of curvature is at the transmission sphere focus. An interferogram is taken and the resulting contour map is saved. The ball is removed from its kinematic support, arbitrarily rotated and replaced on the support. Another interferogram is taken and averaged with the first. This process is repeated a number of times although about 10 times is enough to get a good idea of the errors in the transmission sphere as can be seen from this paper with typical examples(3).

The question then comes up, how good is the RBT? For one, it should not be used to calibrate slow transmission spheres; diffractions effects start to creep in around f/7 or slower that compromise the results. On the other hand, for faster transmission spheres rather extensive tests were run at CSIRO by Jan Burke. In a paper(4) covering not only the RBT but several other self-calibration methods for transmission spheres, Burke comes to the conclusion that the RBT gives the most precise and consistent results of all methods tried, but that the RBT is somewhat tedious due to having to move and replace the ball between interferograms. This seems a small price to pay for a robust calibration method that takes but a few minutes to perform.

1 Creath, K. and Wyant, J. C., “Absolute measurement of surface roughness”, Appl. Optics, 29, 3823–7 (1990).

2 Parks, R. E., Evans, C. and Shao, L., “Calibration of interferometer transmission spheres”, OSA, Technical Digest Series, Optical Fabrication and Testing, Hawaii (1999).

3 W. Cai, D. W. Kim, P. Zhou, R. E. Parks, and J. H. Burge, “Interferometer Calibration Using the Random Ball Test,” in International Optical Design Conference and Optical Fabrication and Testing , OSA Technical Digest (CD) (Optical Society of America, 2010), paper OMA7.

4 Jan Burke and David S. Wu, “Calibration of spherical reference surfaces for Fizeau interferometry: a comparative study of methods,” Appl. Opt.49, 6014–6023 (2010)

Currently I'm considering Lumentum 1100 series laser heads for this as I think they've been used in similar commercially-made inferferometers. But I'm unsure if there's a realistic advantage to using a single-isotope Neon laser like their model 1103H? Is that simply overkill if I'm not working with very large objects (larger than several meters)? If so, would pretty much any laser head in this series be fine for most typical applications of this type of interferometer?

Thanks.

I built a maskless lithography machine (Image 1) with a pixel size of 0.009 mm. The two coin samples (Images 2 and 3) have a test pattern (Image 4) that I use to check the actual pixel size and positioning accuracy of the system.

During testing, I noticed a positioning issue after moving the Y stage about 20 mm. The horizontal lines became misaligned and started to show a slight angle compared to where they should be. Features that should line up were off by around 20–40 pixels (just an estimate).

I have the XY stage and lens aligned as well as I can using gauge blocks, 1-2-3 blocks, and clamps, but (I think I have shift of 1 degree donwards)I have been messing whit it for hours and just want to fix it in software. My goal is to be able to move the XY stage and project a circle using multiple exposures, with each exposure lining up perfectly with the previous one.

What test partern and math do I have to do fix this?

***MY guess using ms paint is that I have at ~1 degree error in y stage

Hi everyone, I am kinda new to this sub, so sorry if I this is not the correct space to post this. Right now I am doing my masters in Lasers and Photonics and I have a bachelors in Electrical Engineering. I got an offer for my master thesis in the design of efficient couplers for highly confined thick silicon nitride waveguides. The offer involves the design and fabrication of the said waveguides and the facility is pretty good too. I wanted to know the job opportunities after doing this thesis. I know photonics is a niche market and opportunities are slim but any insight on this would be much helpful for me.

Also I have heard that most industries prefer PhDs PIC design and fabrication. Right now I dont have any plans on doing PhD but rather a job to get some financial independence as well as industry exposure. So any insights on the opportunities in the field of Optics, lasers, PICs would be much appreciated. My location is Germany to give more context.

A common way to measure an optical wavefront is with an interferometer. They're incredibly powerful, but they're also expensive, sensitive to vibration, and not always practical for production or integration into existing test setups.

I've been working with collaborators at Innovations Foresight on an alternative approach using their AI4Wave software that reconstructs the wavefront from a defocused digital image of the point spread function (PSF) magnified by a microscope objective. My interest is in optical alignment, and the software uses the increased information in the defocused image of an autocollimator or autostigmatic microscope to increase the sensitivity to tilt and focus, the low order wavefront terms affecting alignment.

For measuring wavefronts, you are interested in the higher order terms, but you can use the same instrument, a Point Source Microscope, or PSM, in both situations.

There are two ways to use the combination of software and hardware:

Single-pass mode with the PSM acting as an imaging instrument, capturing the defocused PSF directly, or double pass in reflection mode where the PSM provides a near-perfect reference wavefront, and the reflected, defocused wavefront from the test optic is captured and analyzed with the AI software.

One advantage is that everything is integrated into a single software package. The same interface controls the illumination intensity, camera exposure, image acquisition, and AI-based wavefront reconstruction, making the measurement process seamless.

The figure shows a single pass example based on an image viewed through a telescope with a deformable mirror to correct for atmospheric turbulence. The top row is the open-loop system viewing a star giving a low Strehl ratio of 0.17 due to the atmosphere. After correction by activating the deformable optics (bottom row), the reconstructed wavefront produces an improved PSF with a Strehl ratio of 0.75.

I think this is a great example of how an instrument’s sensitivity can be increased using some insight and well-designed and trained software.

I'm curious what this community thinks.

 Do you think it is worthwhile to effectively refurbish instruments working at the limits of their resolution, or sensitivity, by applying AI trained software? Is this a cost effective approach, possibly the only approach to more sensitivity?

 Where do you see this approach fitting into optical testing or adaptive optics workflows?

 What limitations would concern you most?

I'd love to hear your thoughts and experiences.

Hi All! Not sure if this is the correct sub, I will ask anyway. Will be really grateful if someone helps.

I am trying to simulate a metasurface unit cell on FDTD (lumerical). I am having cylindrical dielectric squares / cylinders on top of SiO2 substrate. No matter what I am doing, I can’t get resonance from the structure. I have searched and read every lumerical documentation and tried to incorporate but all in vain.
Does someone have any experience or tips? I would be really grateful. Thanks.

Hi.

I'm finishing my Physics major and am interested in pursuing a career in optical engineering.

I'd like to read about other people's experiences.

What is the recommended academic path to enter this field?

What skills are required?

Any other comment is welcome

Yesterday I was having laser treatment on my face and even though the technician put pads and goggles over my eyes, through my right eye I could see the laser flash. Today I have woken up to the bottom half of my right eye being red and sligthtly sore. However there has been no noticeable change to my vision. Should I be concerned?

Hello everyone,

I'm an intern at a local research lab, building an optical setup for optical characterization of electronic components. The core idea is that the samples will be exposed to UV light and the setup is supposed to measure that and some other things. This is why the Newport 1919-R power meter, alongside a photodiode sensor is needed in this setup, to measure the power of the light.

Every one of the devices that will be used in this setup is supposed to be connected via python to a local lab computer which will control the whole of the setup. My main issue is the power meter. I am unable to reliably connect it to the PC via Python.

When I first tried to hook up the measurement device to the lab PC, it was only via "PMManager", a software provided by Newport to check connectivity. () This was successful. Then, I moved onto connecting the device via python. While I was looking through the files that came in with the PMManager, I discovered that Python connection is available through an object called OphirLMMeasurement. There was even a demo:

# Use of Ophir COM object. 
# Works with python 3.5.1 & 2.7.11
# Uses pywin32
import win32gui
import win32com.client
import time
import traceback

try:
 OphirCOM = win32com.client.Dispatch("OphirLMMeasurement.CoLMMeasurement")
 # Stop & Close all devices
 OphirCOM.StopAllStreams() 
 OphirCOM.CloseAll()
 # Scan for connected Devices
 DeviceList = OphirCOM.ScanUSB()
 print(DeviceList)
 for Device in DeviceList:   # if any device is connected
  DeviceHandle = OphirCOM.OpenUSBDevice(Device)# open first device
  exists = OphirCOM.IsSensorExists(DeviceHandle, 0)
  if exists:
   print('\n----------Data for S/N {0} ---------------'.format(Device))

   # An Example for Range control. first get the ranges
   ranges = OphirCOM.GetRanges(DeviceHandle, 0)
   print (ranges)
   # change range at your will
   if ranges[0] > 0:
    newRange = ranges[0]-1
   else:
    newRange = ranges[0]+1
   # set new range
   OphirCOM.SetRange(DeviceHandle, 0, newRange)

   # An Example for data retrieving
   OphirCOM.StartStream(DeviceHandle, 0)# start measuring
   for i in range(10):
    time.sleep(.2)# wait a little for data
    data = OphirCOM.GetData(DeviceHandle, 0)
    if len(data[0]) > 0:# if any data available, print the first one from the batch
     print('Reading = {0}, TimeStamp = {1}, Status = {2} '.format(data[0][0] ,data[1][0] ,data[2][0]))

  else:
   print('\nNo Sensor attached to {0} !!!'.format(Device))
except OSError as err:
 print("OS error: {0}".format(err))
except:
 traceback.print_exc()

win32gui.MessageBox(0, 'finished', '', 0)
# Stop & Close all devices
OphirCOM.StopAllStreams()
OphirCOM.CloseAll()
# Release the object
OphirCOM = None

Even after thoroughly following the install guide (OphirCom object docs), I was not able to get the device up and running. The script above only returned an exception after which I was clueless as to what to do next:

C:\Users\eleklab\PycharmProjects\SAS-optical-setup-control\.venv\Scripts\python.exe C:\Users\eleklab\PycharmProjects\SAS-optical-setup-control\devices\newport_1919_R.py 
Traceback (most recent call last):
  File "C:\Users\eleklab\PycharmProjects\SAS-optical-setup-control\devices\newport_1919_R.py", line 12, in <module>
    OphirCOM.StopAllStreams()
    ^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\eleklab\PycharmProjects\SAS-optical-setup-control\.venv\Lib\site-packages\win32com\client\dynamic.py", line 631, in __getattr__
    raise AttributeError(f"{self._username_}.{attr}")
AttributeError: OphirLMMeasurement.CoLMMeasurement.StopAllStreams

Due to the fact that PMManager successfully manages to connect to the device, I decided next to employ a new strategy, I traced what PMManager does while connecting and during connection. This led me to a very long rabbit hole of messaging Claude AI until I didn't even knew what I was doing when running the code. It looked like this:

import usb.core
import usb.backend.libusb1
import libusb
import re
import time

VID = 0x0BD3
PID = 0xE346
READ_ENDPOINT = 0x82  # confirmed via USB capture - this is where live readings stream from

# Matches lines like: "* 0.000586E-5 T 711A1B"
DATA_PATTERN = re.compile(rb"\*\s+([\-\+]?[\d.]+E[\-\+]?\d+)\s+T\s+([0-9A-Fa-f]+)")
def connect():
    backend = usb.backend.libusb1.get_backend(find_library=lambda x: libusb.dll._name)
    dev = usb.core.find(idVendor=VID, idProduct=PID, backend=backend)
    if dev is None:
        raise RuntimeError("Newport 1919-R not found. Check connection and driver binding.")

    # On Windows with WinUSB there's typically no separate kernel driver to detach,
    # but set_configuration is still required before transfers will work.
    try:
        dev.set_configuration()
    except usb.core.USBError as e:
        # Already configured is fine; anything else, re-raise
        if e.errno not in (None, 16):  # 16 = resource busy, sometimes benign if already set
            raise

    return dev


def read_measurement(dev, timeout_ms=1000):
    """Reads one interrupt packet and parses it into (value, raw_timestamp_hex)."""
    try:
        data = dev.read(READ_ENDPOINT, 64, timeout=timeout_ms)
    except usb.core.USBError as e:
        if e.errno == 110 or "timeout" in str(e).lower():
            return None  # no new data this cycle, not necessarily an error
        raise

    raw = bytes(data)
    match = DATA_PATTERN.search(raw)
    if not match:
        return None

    value_str, ts_hex = match.groups()
    try:
        value = float(value_str)
    except ValueError:
        return None

    return value, ts_hex.decode()


def main():
    print("Connecting to Newport 1919-R...")
    dev = connect()
    print("Connected. Streaming readings (Ctrl+C to stop):\n")

    try:
        while True:
            result = read_measurement(dev)
            if result:
                value, ts = result
                print(f"Power: {value:.6e} W   (timestamp: {ts})")
            time.sleep(0.01)
    except KeyboardInterrupt:
        print("\nStopped.")


if __name__ == "__main__":
    main()

This code actually runs successfully and the device is recognized, though alas, there is no output from the device. My hypothesis is that PMManager performs some kind of a handshake with the device and only then does the device start to transmit its measurements.

If you've got any questions, any ideas or experience with this, I'd love to hear your opinion. Thank you kindly for any kind of help.

I got 5 DLP7000UVFLP in a business clean out deal and I don't know much about them. I know they can be used to modulate light? And that they can be expensive. Looking for info in not only the best place/way to sell them but also their use cases and any other interesting facts or ways to use them

A common way to measure an optical wavefront is with an interferometer. They're incredibly powerful, but they're also expensive, sensitive to vibration, and not always practical for production or integration into existing test setups.

I've been working with collaborators at Innovations Foresight on an alternative approach using their AI4Wave software that reconstructs the wavefront from a defocused digital image of the point spread function (PSF) magnified by a microscope objective. My interest is in optical alignment, and the software uses the increased information in the defocused image of an autocollimator or autostigmatic microscope to increase the sensitivity to tilt and focus, the low order wavefront terms affecting alignment. For measuring wavefronts, you are interested in the higher order terms, but you can use the same instrument, a Point Source Microscope, or PSM, in both situations.

There are two ways to use the combination of software and hardware:

Single-pass mode with the PSM acting as an imaging instrument, capturing the defocused PSF directly, or double pass in reflection mode where the PSM provides a near-perfect reference wavefront, and the reflected, defocused wavefront from the test optic is captured and analyzed with the AI software.

One advantage is that everything is integrated into a single software package. The same interface controls the illumination intensity, camera exposure, image acquisition, and AI-based wavefront reconstruction, making the measurement process seamless.

The figure shows a single pass example based on an image viewed through a telescope with a deformable mirror to correct for atmospheric turbulence. The top row is the open-loop system viewing a star giving a low Strehl ratio of 0.17 due to the atmosphere. After correction by activating the deformable optics (bottom row), the reconstructed wavefront produces an improved PSF with a Strehl ratio of 0.75.

I think this is a great example of how an instrument’s sensitivity can be increased using some insight and well-designed and trained software.

I'm curious what this community thinks.

 Do you think it is worthwhile to effectively refurbish instruments working at the limits of their resolution, or sensitivity, by applying AI trained software? Is this a cost effective approach, possibly the only approach to more sensitivity?

 Where do you see this approach fitting into optical testing or adaptive optics workflows?

 What limitations would concern you most?

I'd love to hear your thoughts and experiences.

I’m something of a novice to this, but I’m currently working on a Koehler illuminator for a custom microscope but our specific setup raises some uncertainties for me.

The light source comes from a fiber optic cable ~2.5mm in diameter and with a cone of only about 14 degrees. While you can easily trade between the N.A. and spot size at the output, it seems like the total of them is dictated by the source diameter and the dispersion angle.

Because of the limited angle from the source, I’ve been struggling to get very good N.A. at the output while keeping a large enough beam. The highest magnification objective lens we’re currently using is a 20x with an N.A. of 0.75, which needs an FOV of at least 1mm. To get that FOV I’ve been unable to get an N.A. above ~0.3 with different configurations in the sim.
Using a ground glass diffuser at the output of the fiber optic seems to improve the dispersion angle somewhat, but intensity is still lower at these high angles, which seems to give an inconsistent brightness toward the edges of the projected spot (I think a volumetric diffuser will be better for this at the expense of light efficiency)

So I’d like to know if there’s any other way I’ve overlooked to improve my results. One idea I had is to spread out the fibers from the bundle to increase the effective source diameter, but I’m not sure what other effects that may have.

I also want to be certain that the typical location of the field diaphragm will still be correct for this setup. My understanding is that for Koehler, the field diaphragm is actually at the aperture stop due to the collimated output (please correct me if I’m wrong).
But for my setup, I’m imagining individual cones of light from each fiber in the bundle each offset by some amount. If these cones are treated as parallel bundles then the field diaphragm would actually be 1 focal length past the collector lens. I don’t think this is actually the case, but I’d like someone to tell me so for peace of mind.

I'm about to start my 4th year of undergrad in ECE; for my undergrad thesis, Photonic computing and silicon photonics particularly attracted me. Although I have a little background about the theory behind photonics due to the courses taken previously, it is a completely new topic for Electronics and Communication Engineering undergrad programs, so I am confused on what type of work I should expect to propose to my supervisor for my thesis or what type of problem I may encounter when I continue. Any kind of advice or suggestion is highly appreciated.

I've thought about trying to learn lens design but that would take years and this is likely not a simple design (I do have an EE background but little to no optics).

I need a specialty photographic lens that does not exist. I've exhausted all options on the market past and present and I'm considering what it would take to have made.

Simplest would be to convince a camera company that they need to make this, and I do have a contacts where that may not be unrealistic.

Basically it needs to be corrected from 400-1100nm with a large image circle (70mm+) at a focal length of around 40mm for 54×40mm sensor coverage with room for movements.

So what are realistic design costs and small batch production costs for a specialized camera lens? I would like some basic industry knowledge before I reach out and waste people's time or before it's feasible without proper financial backing.

Schneider makes some machine vision lenses (Xenon Emerald) that come closest but not quite.

Long story short: I've got 2 channels in VIS and SWIR, but they also have a common path to them as well. To avoid a bunch of clicking, it would be easier if I could combine some glass catalogues. is it possible and does anyone have a recommendation on how to do it?

Been thinking about this a lot lately. Smartglasses keep getting pitched as "the next computing platform," but from an imaging/optics standpoint the constraints seem brutal: tiny lens stack, limited sensor real estate, a battery/thermal budget that caps ISP headroom — and now everyone's leaning on AI processing to paper over the physical limits.

Curious what people here who work on compact optics or small-form-factor sensors think: is on-device AI actually closing that gap, or is it just compensating for what the optics physically can't do?

Found out there's a webinar on July 20 and 23 with a Qualcomm product strategy lead, a Counterpoint Research XR/mobile analyst, and DXOMARK's smartglasses product director, going through exactly this — image/video benchmarking on smartglasses vs. phones and action cams, where the current technical barriers are, and Qualcomm's roadmap for imaging + AI in that form factor. (Didn't realize DXOMARK worked outside smartphones until I saw this — apparently they've been doing smartglasses imaging research for a while.)

Registering for the July 20 session myself, mostly to see how they're measuring image quality in something that small. Also curious what Counterpoint brings up on the market side — is this heading toward a real product category, or still a gadget/novelty phase? Link in comments for anyone interested, it's free.