Even STRONGER Garden Laser?!? | Laser classes explained

Hi! Another holiday season successfully completed, another garden decoration laser in my collection. I've already got four different versions and this new, fifth one lacks many features like motion function and remote control. So why would I buy it? Well, my old ones are all labeled class 2 lasers while this new one is advertised as a stronger class 3R laser. It even says 'ekstra lysstærk' on it which is Danish for extra bright. Really? Let's test it! Use laser safety glasses when handling class 3B and class 4 lasers. And if you are unsure of their true classification. Before we test the laser and compare its output to my class 2 lasers we need to figure out what class 3R means. I am used to IIIa and IIIb from laser pointers but where does 3R fit in? A and B are from an old system still used by most laser pointer manufacturers and in some US regulations. 3R is from a revised system and part of the laser classes that have replaced 3A. 3R is therefore a lower class than 3B. Not the most logical order. I try to read the R as an A to remember where it fits in. Let's quickly go trough some practical examples from the different laser classes. Class 1 lasers are the weakest and completely safe under normal use. Either because of very low power output or because the laser beam is enclosed and cannot hit you. Examples from my home are a laser printer and a Playstation. Do note that the laser inside a class 1 laser product can be very powerful. It will be in a higher safety class if taken out of the enclosure. An example is this laser build by one of my kind viewers, Piter Soft. Its laser diode was taken from a DVD burner - a class 1 laser product. Now - at the same power output - it is a class 3B laser since the laser beam is no longer enclosed and can hit me. Thanks Piter for giving me something to demonstrate a change in laser class from the same laser diode. Link to his video on the build in the description. A subclass, class 1M, have higher powered lasers but with a larger beam diameter or larger beam divergence. Their lower energy density makes them safe to use unless viewed through magnifying optics that increase the energy density. Subclass 1C is for highly specialized lasers for cosmetic treatments. Class 2 lasers like this tiny red laser pointer are stronger and only safe for a fast, accidental viewing where the blink reflex will save your eyes. Do not stare into a class 2 laser! Class 2 lasers are only allowed to emit class 2 power as visible light since invisible light will not trigger the protective blink reflex. Class 2 also has an M subclass with higher powers in wider or more divergent beams. Safe for accidental viewing unless viewed through magnifying optics. Class 3R/3A is a very common class for laser pointers. These are only safe if handled correctly. They may be hazardous if the beam or specular reflections of it hit the eye but lower risk than for class 3B. Class 3B are where things get serious. These lasers must include both a safety interlock and key-switch. They are NOT safe. Any hit from a direct beam or specular reflection of it is hazardous. You have to wear safety glasses. Class 4 is the unlimited class. Even diffuse reflections of the beam are an eye hazard and the lasers are strong enough to start fires. A lot of precautions are needed. My highest powered lasers are in this class. For more details and guidance I have linked to a PDF-document in the description. All right. We now know that for visible light a class 3R laser is allowed to emit between 1 to 5 mW. Time to test the optical power output of the new garden laser. I will test the green laser first. Oookaay. They weren't kidding about the stronger laser. I measure up to 29 mW on the green. What about the red one? Up to 36 mW. This is confusing. The new Starry Night is definitely stronger than the old class 2 Starry Night. But one of the class 2 lasers is even stronger. And none of them measure below 5 mW for class 3R. Or below 1 mW for class 2 for that matter. Something seems wrong. For further investigation I will remove the diffraction gratings in front of the lasers to measure more directly on the laser diodes. Turned out to be quite a lot of work for this model. Here's a montage for you. Finally, the lasers are exposed. Time for putting the laser safety glasses on and measure the true strength and wavelengths of the lasers. Green first. Nice! A lot of information here at once. The green laser is around 50 mW. Clearly a class 3B laser when taken apart. The measured wavelength peaks at 531.65 nm. Freaking good, since the central wavelength for a 532 nm laser is 531.65 nm. I should clarify that the spectrometer is limited to a resolution of 1 nm. But in this case it got it right down to a hundreth of a nanometer. 10 picometers. Awesome! There's also a peak in the infrared at 1064 nm. Usually I would call this a lack of infrared filtering on the DPSS laser but I have to correct myself from earlier videos. I'm still learning how to use a spectrometer and got it wrong. Sorry. The infrared detected here, isn't there. It is the second order of the green being detected by the spectrometer. A false reading. The green light is strong enough to be detectable as second order after the diffraction grating used inside the spectrometer. And the second order 532 nm green happens to be in exactly the same place as the first order 1064 nm infrared. The infrared from this green laser is actually filtered away. You can tell it by the lack of 808 nm infrared from the pump diode. Great result! The green is strong and IR-filtered. Now for the red one. This result is more disappointing. Let me explain. The power is around 60 mW, which is good in itself. A class 3B laser. But combined with the wavelength and compared to the green laser, it is not bright. The wavelength is 664 nm - way more than the advertised 650 nm. Sure, some 650 nm diodes are listed as 650 +/-10 nm but at 664 this is clearly a cheaper 660 nm diode. The problem being that 660 looks less bright to us as explained in my video titled 'What makes green lasers the best lasers'. Look at the difference in lumens. The red laser would have been more than twice as bright, had it been a true 650 nm diode. To match the green laser in brightness, it would have to be 840 milliwatts at 664 nm. Or 370 mW at 650 nm. That would never pass as a class 3R. How can this pass as a class 3R with up to 60 mW? I believe it may be due to the test method used in the classification system. The test must be performed at 14 mm distance using a 7 mm aperture. My sensor is 15 mm wide, so I probably should test at a 30 mm distance. Hmmm, it is still well above the 5 mW limit for class 3R. Not sure if I'm doing something wrong here. I would like to hear your thoughts in a comment. I am however sure, that this old decoration laser can not pass as a class 2. It may say below 1 megawatt on the sticker - which is true... - but it also says class 2 laser product. No way this is correct with such strong lasers. Especially considering I have tested it to emit 40 mW of infrared in a Patreon video. Way too much invisible light for class 2. Interestingly, it says class 2R on the box. Did I forget a laser class? No, 2R does not exist. They probably meant to write 3R but made a typo. I'll let you judge whether it was unintentional or not... A big thanks to all my patrons. I'm glad to see the support from more and more of you. It helps a lot! In case you can and want to help me out I have a link for my Patreon page in the description. Thank you! And thanks for watching. Bye for now!

Channel: Brainiac75

Views: 75,794

Keywords: laser, laser pointer, garden, decoration, christmas, power, mW, milliwatt, label, class, classes, 3R, 3A, 3B, 2M, 1M, 1C, test, experiment, science, fun, interesting, educational, learning, safety, glasses, goggles

Id: dd6656CF1IY

Length: 11min 21sec (681 seconds)

Published: Fri Jan 29 2021