Newbie questions

[nevez]

Hello everybody, this is a newbie's first post!

I have always been fascinated by lasers, I own a small 5mw red laser, and now that I have some money (~150$) to spend I'm trying not to waste them! So after a bit of googling I've found this interesting forum, which looks like the right place to ask questions.

I'm looking for a bright pen or flashlight size laser, with a beam powerful enough to be clearly seen at night over a long distance. I'm not interested in burning things.

For what I can understand, red and IR lasers are best for burning but they are not the best for beam visibility over a long distance. I know that the human eye is more sensitive in the green area of the spectrum, so I guess green is the color to go.

My girlfriend obviously doesn't think so, and would like a violet (bluray) laser instead. So, first question:

1) What about the visibility of a bluray beam compared to a green one? Can you mention a power comparison between two lasers that appear to be equally visible at night?

Then, I'm a bit worried about going high power for the risk of damaging other people's eyes. I want a toy (thou a nice one!) to bring with me, not a weapon that I need goggles to operate! I mean: I will never point it directly at someone's eyes but what about an occasional/accidental sweep or reflections from bright surfaces? I guess it goes with the distance too, but in general...

2) Which power do you think is "safe enough" for careful use?

As a last request, I would love if the laser beam could remain tiny over a long distance and not diverge. What's to look for to get this? The lens?

Ok the definitive question: I've seen in the B/S/T section that some people are selling some beautiful lasers (like IgorT), and I've read the newbie thread about optotronics (and their <1.2mrad beam divergence)

3) After reading all of the above: what to buy with 150$?

Thanks for your time
Stephen

PS: I live in Italy, and getting things from outside europe can be costly because of customs... do you know a good europe reseller or a way to get around them?

 

[nevez]

I forgot: I prefer having the possibility to power it with rechargeable batteries.

 

[Mohrenberg]

nevez, if your main feature is visibility, green is the only way to go. in terms of comparing a 100mW green to a blu-ray of similiar visibility....i don't think a blu-ray of that power exists. green is just FAR more visible than other lasers.

i would go with a cheap 50mW green and see how you like it. if it's not for you, then you've only wasted about $30...

...but don't worry. you'll love it.

 

[nevez]

Thanks for your answer. I'll go for your advice, but is $30 really enough for a good quality 50mw green? Looking at the prices of Optotronics Green Pen Pointers, they sell the (tested, IR filtered) 55mw for 99$!!! Also, knowing that for 1.5x bucks you get 3x more power...its a bit annoying!

Do you have another online reseller to recommend, with better prices? Or do you think I should ask here if someone can build it for me?

 

[laserpyro]

Then, I'm a bit worried about going high power for the risk of damaging other people's eyes. I want a toy (thou a nice one!) to bring with me, not a weapon that I need goggles to operate! I mean: I will never point it directly at someone's eyes but what about an occasional/accidental sweep or reflections from bright surfaces? I guess it goes with the distance too, but in general...

I'd Say 30mW max

 

[ZRTMWA]

Supposedly a blu ray needs to be 4 times the mW power of a green to be as visible. Blu rays burn better than reds actually. I dont know of any reselers in Europe but talk to HIMNL9, he's from Italy too. Probably 50mW green max.

I would recommend a 50mW O-like module, putting it in a jayrob host with a recharchable CR123 (power is 3.7V but when fully charged it goes up to (4.2V). Not sure if that would fit your bill. O-like modules also don't have the best divergence. But they along with Rayfoss and Dealextreme would probably be the best to fit your budget. If I was in your place I would save up $50 more bucks and go for an Opto 150mW pen. But you would need goggles with this.

 

[schmag]

I have the Wicked laser core green they rate it at 5 mw. the button kinda erks me from time to time however the beam is quite visible in the evening I think you would love a 30 mW.
over 5 mW pushes you into the class IIIb laser which they say can be harmfull when exposed if you are going for maximum safety I would stay less than 5 mW.
if you still want to have some fun I would around 30 mW and I think the natural reflex of the eye would stay be able to keep up and not do too severe of damage in the event of an accident.
here is the wikipedia entry for laser safety has some good info
Laser safety - Wikipedia, the free encyclopedia

 

[3zuli]

look at DealExtreme: Cool Gadgets at the Right Price - Site-Wide Free Shipping (Page 1) , they're selling a 50mW green pen, which is the same as Optotronics, but it's only 20USD!
and they sell lots of another green (5-500mW), red (5, 100 & 200mW), violet (5-100mW) and blue (5-30mW) lasers

and the visibility of BR beam is very weak without fog or smoke. when I turned on (without) my 100mW BR and 5mW green, the green was 2-3x more visible than BR

 

[nevez]

Thanks for your answers, really appreciated! I'm still undecided between:

1) A DX 50mw for ~$30 - cons: not a solid build, no IR filter, probable >1.5mrad beam divergence, probably 40mw sustained power or less - pros: price!

2) Optotronics 40mw for $77 (should match the above) - pros and cons: reverse the above!

I'm inclined to go for the first... for the same money, I can order a bluray pen too and make my girlfriend happy.

My only doubt is about the IR filtering stuff: do you think it's important to have it with a 50mw laser?!? I've read mixed opinions about this in the forum... to my understanding as long as the IR and green beams cover the same path, it shouldn't be a problem for the eyes, right? My eyes would close anyway. But is this the case? Does the IR beam diverge more?

 

[bobhaha]

well if you want to go with an already built laser go for what the guys said before! other wise I would suggest you try build it your self! i have built a 50 mw laser (wich you can see in my signiture, bottom of the post, click on review here!). with a 50 mw laser you can easily blind someone but with carful use it should be fine to use (im not saying you dont need glasses, but if your careful and really take saftey as you #1 proiety you should be fine with a 50 mw!)

as we all know 5mw of green is the highest "safe" level for our eyes. You can see a 5mw laser in the dark but obviously not as clear as a 30 or 50mw. but you might be able to make a laser from o-like (usually over spec) for around the same money as an already built one.. and it will be slightly higher powered (therefore worth the money!)

but its up to u.. i still advise the use of saftey glasses no matter what the power level..

oh yes in regards to the blu-ray.. im sorry but it is no where near as powerful as the green laser in terms of visibility.. blu-ray is almost UV (ultra violet). UV is invisible light, and is extremely energised, therefore can blind you much easily! i would go with the green if i were you.

btw optronics is better then DX.. just my opionion

hope that helped! -Adrian