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Everybody Needs A: Laser Pointer

Laser pointers, while not entirely necessary for undergrads, are nevertheless a whole lot of fun to play with.  And for formal presentations too, I guess. You can go in several different directions on this one.  I very often see the canonical cylindrical HeNe lasers that operate with a button on the top (left).  It is and maybe a little Spartan, as gadgets go.  Interestingly, these can either be powered in traditional laser fashion, or be an LED connected via blue tooth.   More recently, I’ve become partial to the laser pointers that also act to advance your slides (right).  They can be more expensive, but it’s up to you (or your PI) if the extra cost is worth the fun of not being tied to your computer during a presentation or lecture.

One can purchase laser pointers from almost anywhere, and unless you want something particularly fancy, you can get them for pretty cheap.  If you’re interested in colors, you can get laser pointers in the ubiquitous red or green, as well as violet, yellow, blue, and infrared (though I’m not so sure how that would be useful for everyday use…).  Though I’m sure a yellow laser pointer would really liven up any presentation, I can’t imagine that it would be generally accepted among our community.  Correct me if I’m wrong.

Another more interesting (and fun) direction is a high-power HeNe or GreNe (what people at my University call a green laser.  Not sure if that’s standard, per se).  While difficult to point specifically without the use of a ring-stand/clamp apparatus, high powered lasers are a whole lot more fun.  More importantly, you can go straight from a presentation to examining the effects of the photoelectric effect.  This brings us to our fun-quantum-mechanics-picture-of-the-day! A couple weeks ago, my quantum mechanics lab had the distinct pleasure of quantifying the photoelectric effect.  As you’d expect, this lab consisted of 3.5 hours of adjusting knobs in the dark, resulting in general delirium and sensitivity to light for the rest of the day.  The voltage-meter in the back reads 0.00 because (if you remember your quantum physics) a ‘stopping potential’ had been carefully applied the measure the work function of the collector electrode in this setup.  I apologize for the poor picture quality – this was done with a cell-phone camera!

However we get really cool pictures like the one to the left!

For other fun with GreNe lasers, check out Chiral’s post from a year ago!  His pictures are definately a little better quality than mine.  Also, check back soon for a post about the REU experience from a real live grad student who has gone through one!

6 Comments

  • Mar 8th 201108:03
    by Paul

    Sweet post. I just ordered a blue/violet laser pointer off eBay…didn’t realize they are dirt cheap now. I can’t wait for the yellows to come down in price.

    My current advisor was the first person I saw give a presentation with a green laser pointer. I was an undergrad at the time and had to give the talk after his. There I was—all proud of having my own red laser—when both his talk and pointer blew me away.

  • Mar 8th 201116:03
    by Hap

    I think this NIST article was referenced here last year – it discusses the problems with cheap green laser pointers (ones which lack an IR shield). Some green laser pointers may emit a large amount of their light as IR and outside the margins of the visible beam, so that if you look near the beam, you may receive a blinding dose of IR, while the lack of visibility of the beam means that you don’t shut your eyes (while with other bright sources, you shut your eyes immediately upon registering the brightness of the light source) and so may receive eye damage.

  • Mar 9th 201101:03
    by chiraljones

    “Though I’m sure a yellow laser pointer would really liven up any presentation, I can’t imagine that it would be generally accepted among our community. Correct me if I’m wrong.”

    Beg to differ! I saw Micalizio from Scripps Florida give a talk: black slide backgrounds, and a yellow/orange laser pointer. It was pure class.

  • Mar 9th 201101:03
    by Paul

    Black slides are generally a bad idea. Much harder for older people with bad eyes to read them.

  • Mar 10th 201114:03
    by chiraljones

    huh. I really liked the black slides: pretty easily readable, and color-coded functional groups stood out way better than I’d ever seen with a white background. Then again, the lights in the room were much dimmer than they usually are, and I’m still young enough that my lookin’ balls haven’t deteriorated much yet…

  • Mar 11th 201113:03
    by octopus manifold

    The traditional red laser pointer is a diode laser not a HeNe.

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