The Gauntlet: A 1 Watt Laser Module

March 17, 2012 by 41 Comments

This is the gauntlet; a place where things are tortured in ways that only an engineer could appreciate.

Today’s victim is a 1.0W green laser module, manufactured by Suzhou Daheng under the brand name “DHOM”.

As far as Chinese laser manufacturers go, Suzhou Daheng is about one rung lower than CNI in terms of quality. Although US companies like Coherent blow these guys out of the water, both are still reputable nonetheless.  As far as Chinese lasers themselves go, this one seems a bit conservatively rated; a nice change from the “1000MW 532nm laser cat toy burning module” that’s not too uncommon on dealextreme and the like.

More after the break…
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1 Watt Laser Engraver

September 13, 2010 by 20 Comments

This laser engraver was built using printer parts, a CD-ROM carriage, and some homebrew electronic boards. The laser diode is a 1-Watt model similar to what we saw used as a weak laser cutter back in August. When the width of the material changes the focus of the laser is affected so the diode was mounted on a CD-ROM carriage (in the Z axis) for easy adjustment. The X and Y axes are made using parts from Epson Stylus 800 and Epson Stylus Color II printers. After the break we’ve embedded a video of the machine engraving some wood using EMC2 software on an Ubuntu box. It also boasts the ability to cut paper and some plastic but it can’t compare in power to a CO2-based unit.

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Chinese Subs May Be Propelled Silently By Lasers

April 24, 2024 by 57 Comments

If sharks with lasers on their heads weren’t bad enough, now China is working on submarines with lasers on their butts. At least, that’s what this report in the South China Morning Post claims, anyway.

According to the report, two-megawatt lasers are directed through fiber-optic cables on the surface of the submarine, vaporizing seawater and creating super-cavitation bubbles, which reduce drag on the submarine. The report describes it as an “underwater fiber laser-induced plasma detonation wave propulsion” system and claims that the system could generate up to 70,000 newtons of thrust, more than one of the turbofan engines on a 747.

The report (this proxy can get around the paywall) claims that the key to the system are the tiny metal spheres that direct the force of the cavitation implosion to propel the submarine. Similar to a magnetohydrodynamic drive (MHD), there’s no moving parts to make noise. Such a technology has the potential to make China’s submarines far harder to detect.

Looking for more details, we traced the report back to the original paper written by several people at Harbin Engineering University, entitled “Study on nanosecond pulse laser propulsion microspheres based on a tapered optical fiber in water environment“, but it’s still a pre-print. If you can get access to the full paper, feel free to chime in — we’d love to know if this seems like a real prospect or just exaggerated reporting by the local propaganda media.

[Image via Wikimedia Commons]

Fail Of The Week: A Potentially Lethal Tattoo Removal Laser Power Supply

March 24, 2024 by 7 Comments

Caveat emptor is good advice in general, but in the wilds of eBay, being careful with what you buy could be life-saving. To wit, we present [Les Wright]’s teardown and very ginger power-up of an eBay tattoo-removal laser power supply.

Given that [Les] spent all of around $100 on this widowmaker, we’re pretty sure he knew what he was getting himself into. But he likely wasn’t quite prepared for the scale of the sketchiness this thing would exhibit. The deficiencies are almost too many to number, starting with the enclosure, which is not only made completely of plastic but assembled from individual sheets of flat plastic stock that show signs of being glued together by hand. Even the cooling water tank inside the case is pieced together this way, which probably led to the leaks that corroded the PCBs. Another assembly gem is the pair of screws the big energy storage capacitor is jammed under, presumably to hold it in place — because nothing says quality like a BOM that can’t spring for a couple of cable ties. Click through the break to read more and see the video.

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Homemade Raman Laser Is Shaken, Not Stirred

December 12, 2023 by 12 Comments

You wouldn’t think that shaking something in just the right way would be the recipe for creating laser light, but as [Les Wright] explains in his new video, that’s pretty much how his DIY Raman laser works.

Of course, “shaking” is probably a gross oversimplification of Raman scattering, which lies at the heart of this laser. [Les] spends the first half of the video explaining Raman scattering and stimulated Raman scattering. It’s an excellent treatment of the subject matter, but at the end of the day, when certain crystals and liquids are pumped with a high-intensity laser they’ll emit coherent, monochromatic light at a lower frequency than the pumping laser. By carefully selecting the gain medium and the pumping laser wavelength, Raman lasers can emit almost any wavelength.

Most gain media for Raman lasers are somewhat exotic, but luckily some easily available materials will work just fine too. [Les] chose the common solvent dimethylsulfoxide (DMSO) for his laser, which was made from a length of aluminum hex stock. Bored out, capped with quartz windows, and fitted with a port to fill it with DMSO, the laser — or more correctly, a resonator — is placed in the path of [Les]’ high-power tattoo removal laser. Laser light at 532 nm from the pumping laser passes through a focusing lens into the DMSO where the stimulated Raman scattering takes place, and 628 nm light comes out. [Les] measured the wavelengths with his Raspberry Pi spectrometer, and found that the emitted wavelength was exactly as predicted by the Raman spectrum of DMSO.

It’s always a treat to see one of [Les]’ videos pop up in our feed; he’s got the coolest toys, and he not only knows what to do with them, but how to explain what’s going on with the physics. It’s a rare treat to watch a video and come away feeling smarter than when you started.

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Take The Tedium Out Of Fabric Cutting, Make The Laser Do It

October 29, 2023 by 8 Comments

Fabric must be cut before it can be turned into something else, and [fiercekittenz] shows how a laser cutter can hit all the right bases to save a lot of time on the process. She demonstrates processing three layers of fabric at once on a CO2 laser cutter, cutting three bags’ worth of material in a scant 1 minute and 29 seconds.

The three layers are a PU (polyurethane) waterproof canvas, a woven liner, and a patterned cotton canvas. The laser does a fantastic job of slicing out perfectly formed pieces in no time, and its precision means minimal waste. The only gotcha is to ensure materials are safe to laser cut. For example, PU-based canvas is acceptable, but PVC-based materials are not. If you want to skip the materials discussion and watch the job, laying the fabric in the machine starts around [3:16] in the video.

[fiercekittenz] acknowledges that her large 100-watt CO2 laser cutter is great but points out that smaller or diode-based laser machines can perfectly cut fabric under the right circumstances. One may have to work in smaller batches, but it doesn’t take 100 watts to do the job. Her large machine, for example, is running at only a fraction of its full power to cut the three layers at once.

One interesting thing is that the heat of the laser somewhat seals the cut edge of the PU waterproof canvas. In the past, we’ve seen defocused lasers used to weld and seal non-woven plastics like those in face masks, a task usually performed by ultrasonic welding. The ability for a laser beam to act as both “scissors” and “glue” in these cases is pretty interesting. You can learn all about using a laser cutter instead of fabric scissors in the video embedded below.

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Retrotechtacular: The $175,000 Laser Printer

October 23, 2023 by 38 Comments

Laser printers today are cheap and readily available. But in 1976, they were the height of printing technology. The IBM 3800 was the $175,000 printer to have in that year. (Video, embedded below.) But you couldn’t have one on your desktop. Even if you could afford it, the thing is the size of a car, and we don’t even want to guess what it weighs. The printer took tractor-fed continuous form paper and could do 167 pages a minute at about 150 dots per inch (actually 180 x 144). For the record, that was as much as 1.7 miles of paper an hour!

In those days, people who would use this printer traditionally had massive banks of noisy impact printers. We imagine this device saved many data processing person’s hearing. Compared to a modern laser printer, though, it needed a lot of maintenance. For example, the initial models needed a xenon flash lamp replaced every month, although later models could go years on one bulb. Looking at some of the hardware in the video, it was probably made closer to the end of life for these printers which were made through 1999.

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