Laser recommendations for High School Classroom

[fixorater]

Hey there-

Haven't posted in a long time. I'm working at a Highschool and just found out that our science department has a bunch of optics equipment sitting around they used to use with HeNe <5mW laser. The old laser they used is now broken. One of the teachers was wondering if I could help him find a good replacement laser.

My personal laser interests have been in high powered DPSS green lasers. I'm wondering what you all think would be the best option for a safe but powerful laser that would work both for in door optics demonstrations as well as outdoor astronomy (could still be with AC power hooked up). I'm thinking a 20ish mW green dpss laser would work well but there are obvious safety concerns.

I'm also curious if you all have a particular manufacturer to recommend. There seems to be a huge variability in cost in laser modules.... eg $5 Red Diode lasers vs, $1,500 Lab style diode lasers. We'd want something safe and reliable but not too spendy.

 

[Juggernaut]

You should get the Wicked Lasers Arctic Spyder III in blue, no one will miss out on the presentation.

[Warning can not be held responsible for any "and" all loss of sight / law suits.]

 

[markus_i]

Depends on what type of optics you want to demonstrate. For plain geometrical optics, go with anything in the near red or green spectrum that is safety approved for in-classroom use in your area and provides some means of securely mounting it to your optical bench. I doubt that the 20 mW green will fit the safety requirement - remember, you're not pointing it up into the sky but horizontal at more or less the pupil's eye level, so something in the <<5mW range might be more appropriate.

However, if you want to go for wave optics demonstrations (starting with speckle patterns and going via simple interference/double slit experiments to holography), check the laser's specification with regard to (temporal and spatial) coherence length. I doubt that a simple DPSS laser will be very useful here, you may find that the classical HeNe might actually be your cheapest option.

A third point might be that some of the experiments could require a wavelength in the 600 nm range in order to work out as intended, i.e. to yield quantitative results as described in the manual. I don't know about you or your school, but several of the teachers I knew (both from school and university times - the latter with me supervising their experiments) would be a bit overtaxed with calculating an interference pattern at a different wavelength than from what's written in the manual :-/

Regarding dual-use - well, laser pointers are cheap, while it may take quite some time to set up the bench laser so that the experiments actually work (short rhyme from my school days roughly translates to 'Chemistry is when it bangs and smells, physics is when nothing works'). I'd suggest to go for a second simple laser pointer for the astronomy part.

 

[Xplorer866]

Just watch your eyes and don't point it at anyone or anything reflective and you'll be good.

For in class pointing anything over 20mW of 532nm might be too bright but for astronomy and star gaising you'll need at least 50mW.

http://www.ledshoppe.com/laserpointer.htm

Take a look at those. They're of decent quality for the price. I've bout two of the 50mW pointers. One averages about 62mW and the other 44mW. Perhaps consider that 50mW 405nm (purple) for classroom pointing. That will appear about as bright as 5mW or so of green.

-Tony

 

[bshanahan14rulz]

also take into account that any laser pointer that you use will inevitably be used by some of your students. Either trust your students with a 50mW laser, or get a safe <5mW laser for pointing purposes, where you don't have to worry about that stupid kid in class who tries to blind his friends.

 

[AJ_Dual]

Honestly, for classroom use I'd go with green so it's extremely visible with a simple smoke or fog source.

And I'd go with a lab-style laser so no one is tempted to use it as a "pointer" or screw around with it, dotting other students etc.

Or I'd build one out of a simple module like this one http://www.o-like.com/index.php?mai..._id=18&zenid=af5431612cb9e4237fba53fd5e16d6b6

Bright enough to be seen by students, but still not really dangerous. And what I'd do is put it in a HUGE electronics project box with a big brick or lead weight in it so the students aren't as liable to pick it up and goof off.

 

[fixorater]

Thx guys for the suggestions. As a side question... how does one become certified in the US to operate high powered Class3B and up lasers? I hear a lot about how operators need to be certified but not a lot about who handles the cert process.

 

[Ragnarok]

Imho, for classroom optical demonstrations 5mW is plenty of power for educational purposes and lasers in this power range are easy to replace.

R.:thumbsup: