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Av8tor

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No laser diode is better in terms of beam specs, such as Gaussian beam profile or better divergence. This is because the diodes all have an emitter that even in single mode like the LPC-836, which has a pretty good divergence spec, gives a collimated square or rectangular profile when focused to infinity. To get a TEM00 profile you need a gas laser or a DPSS laser like the 473nm or the 532nm.

BTW, you might want to rethink the use of any laser by your very young sisters. No laser over 5 mW is safe to use by children. The problem with the 405nm laser is they are very close to UV and therefore aren't as visible as a 532nm of the same power. In fact, a 80 mW 405nm laser is hardly visible at all.

Okay, so while diode lasers can have some great performance...the DPSS and gas lasers are on an entirely different level in terms of the beams they produce? I still have so much to learn about lasers and will have to go do some reading to understand the difference between single mode, multi-mode, and the impact of optics on them; but out of curiosity-if I understand it right, DPSS lasers have an 808nm diode at it's heart that projects through crystals which is what produces an output in a visible wavelength. So even though it's a diode, do the crystals do something to shape the beam as well and that's why it will have TEM00 performance even though it's still a diode at heart?

I understand, and I have given that some thought which is why I purchased the kids-goggles for them as I could never forgive myself if something happened to their vision. I didn't plan on letting them handle the J/L as those are too powerful for them to handle responsibly... many 18 y/o's and handle those responsibly! Every so often while flying or listening to ATC you can hear pilots reporting being lased and calling out the position to ATC who reports it to law enforcement on the ground. People don't recognize how dangerous that is to a pilot and how critical a pilot's well-adapted night vision itself is to landing a plane safely at night with the already present challenges but that's a whole new can of worms and fortunately it's never happened to me. I like to introduce them to a world outside of the textbooks they read in school and inspire them to want to learn more about the world around them. With your experience, what is a good age you think it's appropriate to begin getting them introduced to using pointers? By that, do you think its safer that they start with something like a 532nm when they do start as they can clearly see where the beam is being pointed and that's part of the problem with the 405nm? I didn't consider that and it makes sense especially if they were to catch something reflective with it unknowingly. I hoped they could be present while doing things with those and would be able to handle the "<5mW" lasers I ordered off eBay to experiment with the glow in the dark stuff (not by themselves though) but I do understand from reading on here that those ebay lasers are almost always over-spec and I am concerned about that. They're 11 and 14 and we've been teaching them firearm safety with .22's for a couple years and thought it may be a safe step to take into lasers under supervision, but if it's recommended to wait till they get older than that's what I'll do. I accept that I'm new to this hobby and there is much in terms of experience and knowledge that I do not know. I appreciate your feedback and pointing that concern and perspective out.
 



paul1598419

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I guess the simple answer to your question about DPSS laser is the crystal that's being pumped by the diode is acting as a laser itself, independent to an extent of the pump, just like a ruby laser pumped by flash lamps are independent, to an extent from the flash lamp. I could get into the physics of how it all works, but that would be a very long post and unless you have a good understanding of physics, it might not even make any sense to you. It would be better for you to read these things on your own and look up the parts you don't understand. This is not meant as a denigration of your knowledge, just that the explanation is quite involved.
 
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dden4012

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Forum default is safety and caution. We don't want anyone to get hurt. We also don't want bad press. I wouldn't expect to read a 'yeah sure it's ok go ahead' here. What you do is your own choice and consequence. What's available are not kid toys, same with guns. You have to ask yourself if your mature and educated enough to supervise these kids with lasers over 5mw. 'But it was an accident' doesn't cut it as you know. I know adults that I would trust. Your playing with fire no matter how exceptional your sisters may be for their age. If your going to do it please keep this in mind.
There are 3w UV flashlights that can do what your looking for.
Check out DragonLasers 589nm dpss. They have a pen around 5mw and a portable @ 30mw and 50mw.
 

Av8tor

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Okay that does make sense I just got done reading about Theodore H Maiman's Flash Lamp Ruby laser, fascinating stuff I appreciate your explanation Paul! I didn't take it that way at all, I understand thats a lot to type without knowing whether the other person can grasp it all. I have a fair understanding of physics and am fascinated by Nuclear Physics but it's mostly self-study as I didn't go to school for it. Shoulda-woulda-coulda.
 

Av8tor

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Forum default is safety and caution. We don't want anyone to get hurt. We also don't want bad press. I wouldn't expect to read a 'yeah sure it's ok go ahead' here. What you do is your own choice and consequence. What's available are not kid toys, same with guns. You have to ask yourself if your mature and educated enough to supervise these kids with lasers over 5mw. 'But it was an accident' doesn't cut it as you know. I know adults that I would trust. Your playing with fire no matter how exceptional your sisters may be for their age. If your going to do it please keep this in mind.
There are 3w UV flashlights that can do what your looking for.
Check out DragonLasers 589nm dpss. They have a pen around 5mw and a portable @ 30mw and 50mw.

Sorry, I didn't see your reply until after submitting my last post and couldn't figure out how to edit that post and add a quote at the same time.

dden, I respect that and totally understand thank you for the perspective. I didn't know there were UV flashlights available like that so I'm going to go look those up and go that route for now and leave it to the occasional observing for them for the time being. You're absolutely right, I have almost two decades of shooting experience and feel very comfortable supervising them in that environment, but as I'm new to lasers I'd rather have more experience myself in handling them and being familiar with their operation and capabilities before supervising/allowing their operation of lasers. Thank you everyone for your sharing your knowledge and insight and for presenting a different perspective in regards to that. This forum really is an excellent resource and community!
 

Radim

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I did not go through all the answers completely, whatever...
If you want your kids to play with lasers, consider them as playing with guns. Yes, this might be ok, if you are supervising them continuously, educate them in safety and ensure the safety is kept. If you are able to manage that, it is a nice way how to get them interested in science. I would strongly recommend you to get below 5 mW laser for trials of experiments you are about to do and as a first laser you will train them with (remember also you need to train to enjoy lasers with your kids - there are so many things you did not think of and you will realize them only with use of lasers in reality).

Guns do some noise and effects, lasers just silently turn on - this might give you false feeling of safety, remeber that. In addition often it is quite easier to switch the laser on compared to shoot from gun.

You might want to look for some safety protocol used in laser labs etc. To inspire yourself. Good is to write your own safety protocol and keep using it. I also have one for laserpainting - without that it would be extremely dangerous.

Regardig 473 nm laser, the beam and colour are just awesome. If you are interested in portable you might check my review (link in my signature) and also the other reviews of this laser here. If you have any questions about it, you are welcome to ask in the review thread also as the best way to potentially help others who might have the same question.

Enjoy and stay safe.
 
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Av8tor

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Yes Radim, you raise a great point. Just from having experience with one dangerous activity does not translate to safely practicing another, especially one in which I am lacking experience myself. It's easy to be aware of the risks and considerations involving firearms because I've been around them for so long...However I don't have the experience to foresee all the risks and possible dangers involving lasers as I myself am new to them and should develop experience and familiarity before supervising and instructing my sisters on their safe use. I'm glad I said something and got such helpful feedback as I think I let my excitement to share my new passion for this hobby with them without considering my own inexperience in regards to lasers. My youngest sister has been battling brain cancer and I want her to experience and get to see this wonderful world we live in while she can. And you are definitely right about just switching them on, it is a false sense of safety. I really like your recommendation to research and develop a safety protocol, I'm going to start that project now while I'm waiting to receive my lasers through the post and that's a good way to be properly prepared for their arrival.

I know dden recommended Dragon Lasers as they have a true ~5mW pen in 589nm that I'm looking into. Are there any other recommendations about trustworthy vendors to get true <5mW pointers from in different wavelengths that are reasonably priced? I am leary as I've seen a lot of talk that lasers that are advertised as being <5mW are usually overspec sometimes by quite a bit.

Yessir, I saw your review on your 473nm, in fact it was part of what motivated me to go with Jetlasers! Your laser paintings are something to be admired, I've never seen anything like that before!!:drool:
 

Radim

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Oh, I'm sorry about your sister, hopefully you can reach your goal. Our world is awesome and beautiful and there is always something to explore.

Consider also getting some optics for experiments (but be extremely carefull with them - it might be extremely dangerous in addition to laser potential dangers).

In deed you might adapt your safety habbits from firearms experience you have. For example - treat batteries as ammunition, main power switch as safety (if the laser has two stage switch at least before fired - Dragon Lasers Spartans for example have only one switch - analogy: no safety on gun) and fire button as a trigger (finger off untill you are completely sure you want to fire it). Even there are some specifics - beam never ends, reflects from some objects etc. there is a lot of similarities.

You might even discuss your safety protocol here if needed, also I think you know about it, but a lot might be found at www.laserpointersafety.com. It is always good to include emergency scenarios in case of accident (even not likely to happen if you follow a good protocol, but you never know), contacts for local medical doctor specialised on laser injuries or eye specialist, just in case something happens to have it handy. If accident happens time plays crucial role for reducing the impacts of the injury.

Regarding low power greenie, ask Jack from Optotronics. Point out you want definitely below 5 mW, as they might be overspec a bit. If you tell him your purposes, he will understand your needs better. Also you might consider to use rechargable AAA batts as they have lower voltage (1.2 V) compared to alkaline (1.5 V) and lithiums from Enegizer (1.8 V dropping to 1.5 V under load). With using lower voltage you might reduce the power a bit (however it depends on the driver and batts - internal resistance might be different even for same type of batt, therefore voltage drop under load as well).

And thanks, I appreciate my review was useful for somebody. Also thank you for your feedback on the laserpaintings, I'm about to do more soon. But I was busy lately or the weather was not good when I had free time for that. So, maybe tonight I'll try to do long time desired artwork. ;)
 

Rivem

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Welcome Av8tor! It's good to see another Coloradoan on the forum.
 

Av8tor

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Thank you Radim, you are full of wonderful ideas! Yes, your analogy with firearms was spot on to what I was thinking but as you pointed out and after thinking about it, there are some differences which could be very dangerous as the likelihood of having a direct ricochet from a firearm is much less than the guarantee it is with a laser if aimed at a mirror or something reflective; and where most firearms have a 4-8lb trigger pull...activating a laser can be a simple misplacement of a finger (Both are dangerous but I can imagine it's much easier to do activating a laser switch if not paying attention or trying to grab one that's rolled off a table or something similar.) And as someone pointed out, I think you or Paul about how 405nm can be deceptively powerful. You know that a bullet is going to hurt no matter what caliber it may be, but I don't think it's as considered how much a beam of light can hurt and how fast it can change your life like it should be.

I didn't even think about optics, that is a great idea! I can see the importance of being VERY aware while using those, I read a PDF last night about laser accidents at some very well known laboratories involving well experienced scientists with their experiments and it's a humbling reminder that anyone's life can be changed in a second no matter how much experience one has involving lasers if one disregards safety.:eek: Do you think something like this would be a good place to start? Also, I've seen some lab-laser experiments seem to use a pegboard and have a type of 'wall' built up around it, do you think that is necessary or can simple tabletop be used if setup appropriately?
https://store.schoolspecialty.com/O...item=3322663&gclid=CIz_7s-CltQCFVG4wAod4UoKhA

Okay thank you, I'll reach out to Jack and see about ordering one from him. I looked at the Dragonlasers 589nm 5mW as was suggested and phew! Thats definitely one to add to the collection but my wallet would kill me if I ordered that right now lol That'll have to wait till next month.

Absolutely, you're welcome! Thank you for posting such a thorough and visually appealing review ;-) I drooled over your review and Gabe's of his 300mW 532nm for a couple days before pooling the trigger on my Pl-E's! I'll have my eye on your thread patiently (as much as I can) awaiting some more laser paintings!

Hello and Thank you Rivem, It's nice to be on here!! You know it's a nice collection you have when it has it's own link!:worthy:
 
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paul1598419

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Where in Colorado are you living? I was in Lakewood and Aurora, both suburbs of Denver for 8 years back in the 1990s. I enjoyed my stay there, but was angered when they built Coors field for the Broncos at taxpayer expense. I thought there was nothing wrong with Mile High Stadium.
 

deadshadow

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No laser diode is better in terms of beam specs, such as Gaussian beam profile or better divergence. This is because the diodes all have an emitter that even in single mode like the LPC-836, which has a pretty good divergence spec, gives a collimated square or rectangular profile when focused to infinity. To get a TEM00 profile you need a gas laser or a DPSS laser like the 473nm or the 532nm.

BTW, you might want to rethink the use of any laser by your very young sisters. No laser over 5 mW is safe to use by children. The problem with the 405nm laser is they are very close to UV and therefore aren't as visible as a 532nm of the same power. In fact, a 80 mW 405nm laser is hardly visible at all.

hey paul,just wanted to mention that all people see the 405nm wavelengh different as you already know,my eyes are very sensitive to the 405nm wl in the dark,i can even hardly see the beam of less than 2mw and everything more than 5mw have a very nice beam from all the angles to my eyes :)
 
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Radim

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There might be found a lot of optics on ebay and so. Even many laser companies sell some or are able to deliver it even if not in offer. I use various lenscaps for convenience with fixing it on laser, still they are limiting my possibilities, so I'll go for more versatile solution. I'm about to order the kit from Optotronics - the one with 5 mW pointer. Much more possibilities with it. I'm not sure about the kit you posted, it seems to me to be just for educational purposes on certain topic only - good for schools, but you might get bored from it soon.

You might also consider optical bench, but these at professional quality are expensive. For basic optics experiments firm table should be sufficient. Unless you go for vibration sensitive stuff like building interferometer or doing holography. However even some simple holography can be done using box of sand. Still for holography you need special lasers with long tempral coherence - these are very expensive. Still certain diodes and HeNe laser might be sufficient for small objects. For cheap cost about hundred bucks you might get LitiHolo kit (everything is included there). I've no experience with that, but it seems to be fun with that.

Many members here use tripods with clamps to fix lasers. Or look up for Brucemir's artworks, great indoor laserart, very creative and complex. You might notice the stands he uses for fixing optics.

Just one point for optical setups - it is requested by lab laser safety protocols I've seen to be at waist-belly height and no beam should be brought above this level. For laserpainting it is not possible, so I use safe zones instead, I use glasses and when approaching camera to start the exposure for example and camera is in not safe zone I turn back to the source. Still special caution is needed. Like yesterday...

Just make sure lasers are fixed firmly, fall of laser in operation might cause you serious and severe injury as it happend the member with 1 W blue when doing liquid sky effect and laser fell off his chair - this is legendary (but true) thread here when someone needs example of accident and how easy it is to happen faster than you blink. That member even made his damaged retina pic as his avatar.
 

Blaster

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Hi and welcome to the forum thanks for such a great introduction, hope you enjoy your time there, there's a lot here to read years worth regards blaster
 




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