#Concept-Crafted-Creations #video about #manufacturing the #solar-energy collector based on the James Webb Space Telescope with 18 mirrors costing US$5 each. Explains that the JWST uses gold so it can do better infrared imaging. He made some small concentrating mirrors by letting heated plexiglas discs sag into a mold made with #3D-printing, which seems like an interesting technique for #optics in its own right, though possibly not imaging optics. Rather than for the final solar concentrator, this was used for a goofy invalid experiment to compare “silver” and “gold” which were represented by colored spray paint, and the “#energy” gathered was measured by some unknown kind of light sensor #electronics. For his big collector, he used not just 3-D printing but also #laser-cutting on wood and assembly with screws. He also used a laser-cut alt-azimuth wood base with a giant gear for #solar tracking. He explains the three-point screw-and-compression-spring mounting that makes each of the 18 mirrors alignable, using TPU accordions for the compression springs; the mirrors themselves are laser-cut plexiglas with reflective window film stuck to it. He was hoping to sag these plexiglas hexagons into a mold in the same way as for the small test mirrors, but his microwave oven (which must be what he used for the others) damaged the window film, so he ended up heating them to only 100° or 120° and clamping them into a mold (with a laser-cut custom clamp) instead of just letting them sag under their own weight. His aluminum collector plate with coolant grooves running through it cost him US$171 for #PCBWay to custom-machine, making this a very expensive solar collector, though he thinks it’s cheap. Also he’s in the Netherlands, where it’s cloudy a lot, especially in winter. Comments mention that blackening copper with liver of sulfur makes a good solar-collector material.
on 02026-08-15very strange nonlinear #optics can produce subharmonics and difference frequencies of optical signals
on 02026-07-30apparently a 77-minute #Gelbart #lecture #video: “Summary of Sensors, Limits of Accuracy, and Unusual Sensors, by fizzym” about how digital calipers were originally inductive, switched to capacitive (bad in a machine shop, and also using incremental encoders), and some have now switched back to inductive. Also talks about #Tellurometers, and material stability with time (he says steel and regular invar shift by 1 or 2 ppm in a year) and recommending Rolt’s #metrology book Gauges and Fine Measurements. And how laser microphones bounced off windows work. And how the Russians bugged the US embassy. And nonlinear junction detectors for finding bugs, using a second-harmonic narrowband filter to detect parts per billion of nonlinearity in the reflected signal. And how you detect eyes looking at you by scanning the scene around you with a 10mW 830nm laser and looking for retroreflections a million times weaker (10 nanowatts, a “huge signal” in #optics).
on 02026-05-17#optics #video #toread about a lensless camera with scotch tape by #okooptics
on 02026-04-28#Veritasium #video about #ASML #EUV #photolithography machines, which apparently cost US$400 million each. Explains #optics a bit, including defining NA (as the sine of half the cone included angle) and the Rayleigh equation. Traces the #history through Kinoshita and Andrew Hawryluk, with an #interview with the latter, and extensive interviews with people at ASML. #precision
on 02025-12-31#optics #precision #manufacturing #video on making things flat. Like, optically flat: 50nm peak to valley, 1nm RMS. With a “planetary polisher” or “continuous pitch polisher”, which rotates a huge pitch lap underneath a “bruiser plate,” ideally made of something like Zerodur, carrying the blank or blanks. Helpfully explains that the grooves in the pitch lap prevent aquaplaning, just like the grooves in a car tire #tread. In order to avoid having to run his machine continuously, using a many-pole #brushless motor obtained from #hoarding a washing machine, he uses a very high-viscosity pitch (100× more than normal) in a very thin layer, which he initially flattens with a granite plate for 15–20'. His pitch lap is supported on five rollerblade wheels, and he controls motor speed with a VFD. Matching the angular velocity of the lap and the blank results in constant grinding across the surface.
on 02025-12-17very nice plots of Thor Labs’s mirrors’ reflectivity/absorbance/#emissivity over visible and infrared wavelengths. #optics
on 02025-12-13#Cylo #video of diamond-turning a mirror after initial rough milling. #optics #manufacturing #toread
on 02025-12-10#Alpha-Phoenix #video of a laser pointer at 2 billion frames per second. With a single pixel, so he then scans it over the setup with a gimbal-mounted mirror, and repeats the experiment, hundreds of thousands of times (3000 times per second). “Every one of these pixels was recorded separately, as a 1×1 pixel video!” Integrated encoder feedback in the motors was the key. He geared the pitch servo down with a timing belt to get better angular resolution because Katić, Domitran, Horvatek, and Lagator wrote a paper saying timing belt transfer accuracy was fine for angle metrology applications. “After figuring out which LLM code snippets were useful and which LLM code snippets were the reason I’d been frustrated for hours...” His optics train is one lens and one pinhole and, I assume, one photodiode. No, holy fuck, it’s a photomultiplier tube. His data acquisition rig is a benchtop 2Gsps oscilloscope, a Siglent SDS824X HD, 200MHz, 12 bits. He points out that the analog signal path amounts to a 58-frame delay line. To include the synchronization signal on the same line (because the scope can only do 2Gsps on one channel), he used a 500ns coax delay line from the laser. #precision #optics #cameras
on 02025-10-17#video tips on #manufacturing #optics with silicone molding. He likes using the plastic cups the mold was made in to hold his mold halves together, injecting his resin with a syringe through aquarium tubing into the bottom of his mold to drive bubbles out the vents in the top, Smooth-on Crystal Clear 200 resin (despite only having 20 minute pot life), degassing, casting in a pressure chamber, including a straw or even funnel extension for the sprues/vents to provide an excess of resin, drilling your vents and sprues with hardware-store brass tubes with sharpened edges, and hanging the lens up from a sprue for a week to let it fully cure (to avoid getting flat spots from the lens’s weight during that time).
on 02025-09-29#video by #Breaking-Taps on #manufacturing optically-clear epoxy copies of glass lenses by casting in silicone molds (Smooth-on Mold Max XLS); he gets 8.90nm RMS surface roughness on his copy, worse than the 1.74nm RMS surface roughness on the glass original, according to his AFM, plenty good for #optics. It worked easily for 10mm lenses, but it was difficult to get the process to work with 100mm lenses, with hazy surfaces (due to mold release), deviations from sphericality, etc. He says you can’t polish, lap, or grind plastic, which I don’t think is true of all plastics. A reader says, “Hey, I just want you to know that you can actually polish a plastic lens. I’m a lens maker in Canada and everything we do is plastic. We don’t always do PC but we do a ton of other materials. Everything gets polished.
we use a liquid polish and some abrasive pads, and I’m not exactly certain what kind of polish you could use for it, but it’s definitely something we do.”, and another comments, “I worked for years in a surface lab lapping and polishing plastic lenses all day. It’s absolutely practical”. A third says, “YES you can polish plastic as good as you can polish glass! You just need to use finer grit paper or less abbrasive [sic] materials and also you get the best result if you do wet sanding and then wet polish with VERY high grit sandpaper and oil or water. I do it myself so YES you can!” He sputtered metal (60nm silver) onto the glass as an alternative mold release that wouldn’t create micron-scale roughness. Smooth-on Accel-T tin-cure accelerator additive caused more shrinkage during curing of the silicone, ruining the figure of his mold. Relatedly, he says you want the resin to cure as slowly as possible, because fast-cure silicones shrink more. Mold Max XLS he says is 1000ppm shrinkage, EpoxaCast 690 is 2000ppm.
on 02025-09-28near-field #diffraction is "Fresnel diffraction" #optics
on 02025-08-24"Superlenses" to overcome the diffraction limit, #optics #paper from 02008
on 02025-08-24#video on #laser diode wavelength stabilization by adjusting the drive current and temperature (using a resistive heating element!) to compensate for wavelength shifts. Demonstrates “mode hops” on an oscilloscope; the initial heating using a temperature sensor (a transistor I think) is to get it to a mode-hop-free region, and then the current is PID-controlled to stabilize the wavelength, and a second control loop adjusts the temperature to “desaturate” the current controller. He says he got the wavelength stabilized to ±2nm “over a range of 200mm”, which I think means 10⁻⁸, not 2/555 or so. #optics #toread #hardware
on 02025-04-12#video on a Luxmux’s “Ultrawide Tunable Fabry Perot #Laser G5” #optics
on 02025-04-04#Applied-Science had to replace the image sensor chip on his camera PCB many times in order to use an oil-immersion microscope objective backwards as an f/0.38 lens (f=4mm). #electronics #hardware #optics #video #bootstrapping #toread
on 02025-02-05“Neural nano-optics for high-quality thin lens imaging” #optics #paper #PDF
on 02024-11-22#video #toread on galvano-gimbaled mirror #optics
on 02024-09-24#video about #optics microlens arrays as a “key to our sci-fi future”. Nanometer-sized pillars on a silicon wafer; company is Metalenz. Video (by "Freethink") is pretty clueless and gives no real information about #metamaterials except that they can do polarization imaging. Lots of talking-head filler. #Plonk
on 02024-09-17#video #toread about #3D-printing #optics components (not lenses, prisms, and mirrors tho) #Breaking-Taps
on 02024-09-17#video on #Cylo problems in #precision #optics #manufacturing #mechanisms: “Nanoscale air bearing vibrations cause surface finish issues in diamond turned surfaces.” 50 nanometers of vibration gave a “hazy” surface finish, although you’d think it wouldn’t.
on 02024-09-15#video somewhat poorly explained on #3D-printing #kinematic-coupling #mechanisms for #precision #optics. He shows his optical kinematic mount for a long time without showing what he’s going to use it for, instead trying to explain it in words. He has a green diode laser module mounted in a 3-D printed thingy which is pushed apart with screws (with ground and buffed ends rather than ball bearings as you’d expect) running through soldering-iron-staked brass inserts, pushing on flat stainless steel plates, pulled together with tension springs pulling on bits of welding rod, and pivoting on a 7mm stainless steel ball bearing; all the metal parts are inserted into the plastic framework. I think the idea is that you slide this thing around on a surface and the angle of the laser changes to show you the angle of the surface. The laser module is clamped into the thing with an M4 screw tightening a sort of plastic shaft-collar arrangement around it, and a Powell lens (?) turns the laser beam into a line, which I guess lets you determine the surface’s angle in both dimensions at once? He thanks “Zachary from Breaking Taps” for tips. He’s planning to focus the laser through a spatial filter with a microscope lens to clean up the dirty “cat’s-eye” beam. He’s going to put ball bearings in the base of the mount too, to hold it up (bizarrely, four of them instead of three!), and there’s a screw in the middle to hold it down to a screw hole on the optical breadboard. He's planning to replace the plastic with aluminum or stainless steel. In the comments, @bansci recommends using #OpenFlexure designs and captive nuts rather than heat-staked inserts.
on 02024-09-15#Thought-Emporium #video on holographic #optics and how commercial holographic patterns are hot-stamped, but he’s making computed holograms with a film camera and Rafael de la Fuente’s Diffractsim. Explains how diffraction works with animations and shows many other diffraction phenomena, including the Arago spot. Photographs a zoneplate on Ilford ISO 50 pan film; plans to use Adox CMS 20 super-high-resolution film. Projects the hologram from the film negative with a pinhole-aperture white LED rather than a laser. Also hopes to use photon sieves in the future.
on 02024-09-10#video on #optics at #ASML by Huygens Optics, discussing how getting more than one order of diffraction from your shadow mask into your imaging optics can improve the resolution of the resulting image. #precision #manufacturing
on 02024-09-02#video on #manufacturing #optics by #machining pure copper (to eliminate inclusions enriched in other elements that can cause tearout) with a monocrystalline diamond cutter. Lots of footage from atomic force #microscopy and scanning electron microscopy. To eliminate 50μm steps between adjacent passes of the diamond milling cutter, he switched to 0rpm, just using his milling machine as a sort of shaper, and got the surface roughness down to about 13nm. #Breaking-Taps
on 02024-08-28#Tech-Ingredients #video about #manufacturing diffraction grating #optics in chocolate
on 02024-06-12#PDF #paper from 02016 by Tomes and Finlayson: #bootstrapping an integrating sphere for #optics measurements; they painted it with barium sulfate suspended in PVA glue thinned in water for spraying, with five wet-on-wet coats followed by 10–15 (??) dry dust coats, getting 90–95% reflectance and a flatter spectrum than titanium dioxide, comparable to commercial Avian-B.
on 02024-04-05#EEVblog teardown of a CCD scanner array from a fax machine. He mentions at about 2’20" that people complain when he pronounces “LEDs” as [lɛdz]. Most of the video is microscope footage. There’s a massive array of tiny lenses which he describes as “kind of like an optical zebra strip”, which seems fair, but it turns out it’s called a “rod lens array”; the lenses are something like ten times as thick (5mm) as they are wide (0.5mm?), so presumably what they’re doing is putting a virtual image of the page very close to, or on, the CCD itself. The 25 or so transistors attached to each pixel of the sensor array makes me wonder if it’s maybe actually a CMOS sensor rather than a CCD, since a CCD can serve as its own shift register. #hardware #video #optics #electronics
on 02024-04-04#Alpha-Phoenix first-surface mirrors. #optics #video he’s using the silvering process from the Tollens #materials test (silver nitrate, lye, ammonia, and a reducing sugar). Probably this process would be useful for #electroplating non-conductive objects as an alternative to graphite paint. He prints some things in an unspecified plastic with FDM #3D-printing, sands them, applies a two-part epoxy filler (“XTC-3D”) to smooth the surface, and silvers it by spraying precursors from a commercially-bought silvering kit onto it. To keep the resin from dripping off before it cures, he rotates a part slowly on a slanted axis so that it drips back to where it started. This introduced errors far too large for #optics. To try to silver the surface evenly he added a surfactant. In one batch, his epoxy reacted with one or more of the sprayed precursors, getting silver but with a terrible surface finish. In fact, that kept happening afterwards; he found that he had to cure the resin indoors (heat? humidity?) and needed to have the resin component ratio skewed toward component “A”.
on 02024-04-03#Alpha-Phoenix first-surface mirrors. #optics #video he’s using the silvering process from the Tollens #materials test (silver nitrate, lye, ammonia, and a reducing sugar). Probably this process would be useful for #electroplating non-conductive objects as an alternative to graphite paint. He prints some things in an unspecified plastic with FDM #3D-printing, sands them, applies a two-part epoxy filler (“XTC-3D”) to smooth the surface, and silvers it by spraying precursors from a commercially-bought silvering kit onto it. To keep the resin from dripping off before it cures, he rotates a part slowly on a slanted axis so that it drips back to where it started. This introduced errors far too large for #optics. To try to silver the surface evenly he added a surfactant. In one batch, his epoxy reacted with one or more of the sprayed precursors, getting silver but with a terrible surface finish. In fact, that kept happening afterwards; he found that he had to cure the resin indoors (heat? humidity?) and needed to have the resin component ratio skewed toward component “A”.
on 02024-04-03notes on chalcogenide oxygen-free glass #materials, which are useful for IR #optics because they're transparent to LWIR and MWIR, which the silicon-oxygen bond slurps up
on 02020-11-12a 400× light microscope might reasonably be able to resolve 300 nm, just above the Abbe #diffraction limit for visible light. #optics #microscopes
on 02016-10-06