Laser Smackdown: The Most Amazing Use of a Laser?

Way back in the early days of ScienceBlogs, I ran a competition of sorts to determine the greatest physics experiment in history. I collected a bunch of nominations, wrote up a post about each of the top 11 entries, and then asked people to vote for their favorite.

In honor of the 50th anniversary of the laser, let's take a stab at something similar:

What is the coolest thing you know of that's done with lasers?

Lasers are all over the place these days, from UPC scanners to telecom networks to optical drives to hospitals. All sorts of fascinating things have been done with lasers over the past half-century. Which of those things is the most impressive?

It could be a commercial application, it could be an everyday technology. It could be something few people outside the field of laser science have ever heard of. Whatever you think is the most amazing thing done using lasers, leave your nominations in the comments. I'll compile a list, write up a blog post detailing the pros and cons of each, and then we'll have a vote and officially declare your favorite the winner.

Nominations will be open until Monday, Feb 8th, at which point I'll put together the list, and start posting write-ups about the top nominees.

(This is not in any way affiliated with the APS-sponsored LaserFest program, on account of I just thought of it now, and am posting it on my own blog.)

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You might reasonably ask what my nomination would be. This should be obvious from the fact that my research has all been in the field of laser cooling.

Other obvious candidates are things like laser eye surgery and ultra-precise frequency measurements with femtosecond laser frequency comb sources. OK, those are obvious to me, at least.

Determining the distance from the earth to the moon.

Dog toy. Hands down:

The _potentially_ coolest thing has to be laser-induced fusion. If that ever becomes practical, it would be one of mankind's greatest inventions of any type, for its ability to both save the environment and create wealth - a combination rarely seen. But it may be one of those technologies perpetually 20 years in te future, so we should re-visit this question when we're old geezers.

Smart-aleck suggestion: Laser Floyd (real groovy, man!). Serious suggestion: Lene Hau's "light-stopping" experiments at Harvard in 2001.

By Sebastian Thaler (not verified) on 26 Jan 2010 #permalink

The destruction of Alderaan.

The destruction of Alderaan.

The destruction of Alderaan was clearly not done by a laser, but rather some sort of particle-based weapon. You can clearly see in the footage of the event that several separate beams merge into one in a region of empty space, which would not be possible with light.

Waitaminute. Did I say that out loud? Never mind. Move along, nothing to see here.

I'll agree with keith8: bouncing a laser beam off the Moon to measure its distance to, what was it, 12 significant digits? That's both awe-inspiring and literally out of this world. It may be conceptually simple, but it's still mind boggling.

-- Steve

Optical storage media. It's amazing to me that an inexpensive and simple to manufacture device can probe such small length scales as those found on CDs, DVDs and now Blu-rays. It's not nearly as impressive in some ways as the immense usefulness of lasers in laboratories, but it's somehow more amazing for how it has transformed society and found truly ubiquitous application.

LIGO. Also, barcode scanners that allow you to buy groceries without having to interact with a single human being.

Telecommunications is the clear winner for me. It's not as sexy as precision measurement or optical cooling, but without telecomm lasers, the single-mode optical fibers that just won the Nobel wouldn't be one of the central techologies in communcations.

Laser pointers. Lasers in everyday life, used without even thinking about them as cat toys and office presentation assistance, that have brought the saying "do not look into laser with remaining good eye" to the masses.

When the media has to do a massive campaign of "do not do stupid s*** with your lasers" such as they did with teaching people not to point them at airplanes and helicopters - that's when you know you've reached public saturation.

Well, I vote for using lasers to win $$ from NASA in the Space Elevator Beamed Energy Competition. But I would!


I second Chris #12's nomination of the CD and its follow-on technologies. There is a firm dividing line right about my age: people older than I had record players, people younger than I generally did not.

By Eric Lund (not verified) on 26 Jan 2010 #permalink

Not serious: Star Trek (are phasers lasers?)

Serious: Spasers. And I'm not just biased because I go to Purdue. :p

By Christopher H (not verified) on 26 Jan 2010 #permalink

How about making "stars"?

Observatories use 15 Watt lasers to excite the sodium layer 55 miles up. This creates a bright point source which can be used to calculate the signal distortion due to atmospheric turbulence.

They also have to hire "spotters" who just stare at the sky and yell "plane" (okay, they press a button) whenever they see an airplane passing by.

I would have to go with LIGO/LISA.

I second #6, Emory's nomination.

my first thought was laser cooling. but the gravity wave experiments are cool too.

Laser surgery to repair torn retinas....for I have seen the light of the Argon laser and it is good!


Put some on the head of some fricken sharks, which then had fricken laser beams attatched to their heads.

Cavity-enhanced frequency comb spectroscopy. How cool is it to be able to detect all kinds of chemicals at extremely low levels, all at once? I like the potential medical apps, as well, such as testing blood sugar and insulin levels by analyzing the breath (i.e. without needing to prick a finger), plus lots of other medical diagnostics from the breath. Talk about non-invasive. Seems pretty sweet. Plus, the frequency comb looks like a very pretty rainbow.
But, dang if telecommunications and cd/dvd/blu-ray technology doesn't kick ass, too. And lasik. I mean, correcting people's eyesight is hard to beat. And I love optical trapping. It's a real-life tractor beam! Crap, I think I just cast 6 votes at once.

Shana @4 - That would have been my next choice. (Both my choice & hers involve things my husband lead/invented.)


The most amazing: has to be (for me) the Theta Pinch experiment I saw at Culham Labs in the UK in 1969 (I'm searching for a reference). The stats: housed in an aircraft hangar-sized building. Most of the building was taken up with a 1 Farad capacitor (yes, 1 Farad) which was charged to 10^6v and then discharged in about 75 nsecs through a single turn coil. That coil was a sheet of metal about 10' wide wrapped once around a 12" diameter tube, and the tails were clamped together with massive concrete slabs to counter the electrostatic repulsion force from the rush of electrons through the circuit on discharge. The magnetic field produced was used to compress a plasma injected into the tube to the point of fusion (or near). At the same time, a 500KW pulsed synthetic Ruby laser is flashed lengthwise through the compressed plasma and very high speed photographs / movies taken via peepholes along the side of the tube. The purpose was to investigate how and why plasma at those temperatures exchanged places with the compressing magnetic field lines.

So I know what a 500KW pulsed Ruby looks like, and also a 250KW. The guide held one of each in one hand and jingled them together (OMG!). About 12" long by 1" (250KW) or 2" (500KW) diameter.

Do not point at remaining eye. In this case, do not point at remaining neck stump. You did NOT want to be in the same room when that thing went off.

The other, more subtle, is volumetric holography, where a single substrate can record multiple holograms separated by incident angle of laser illumination.

By Gray Gaffer (not verified) on 26 Jan 2010 #permalink

Naturally that laser device Goldfinger used on Bond. To go with that most memorable line "Do you expect me to talk?" "No, Mr. Bond. I expect you to die."

My serious suggestion would be one of the laser cooling experiments, but I'm undecided which one. I'm leaning towards macroscopic interference between two BECs, but that would be beat by trapping an anti-Hydrogen atom (real soon now?) However, my experience is that students are more amazed that lasers can be detected after being bounced off of the moon than they are about them being used to push atoms around.

My less serious one is to note that there are laser pointers and then there are frigging laser pointers: the high power green ones that can be used to point out stars in a dark sky and whose misuse (likely the case in the crackhead video) is a felony if it involves aircraft.

By CCPhysicist (not verified) on 26 Jan 2010 #permalink

My vote also goes to laser cooling for Bose-Einstein condensation.

Regeneration of temporal optical solitons upon tens of millions of km in optical fibers loops is also very cool.

I'll also mention Dehlmet trap experiment. No fancy physics here, but being able to "see" an individual atom with my bare eyes was probably the experience that got me into laser science.

I'd say frequency combs - they are so valuable to both applications and basic research: Rapid spectroscopy and ID of chemicals, timekeeping and frequency standards, distance measurement, ultrahigh resolution spectroscopy. At one extreme you use them for attosecond physics, but slice the spectrum to remove a single stabilized line and you are suddenly able to measure the narrowest atomic transitions around. They also derive from mode-locked lasers, which are central to all telecom...

For pure basic research, I'd say BECs/laser cooling. This is neat, but doesn't yet have the proven applicability of frequency combs.

And for the "news of the weird" side, Kellogg's laser engraving of individual Corn Flakes with their logo so that you know that the soggy flake you are eating is not some imitation.

The coolest use of a laser is to make other lasers, such as pumping a dye laser or as the source for an Optical Parametric Oscillator laser-splitter.

This is actually pretty awesome, as now you can tune your lasers as needed.

Gamma Ray lasers pumped by thermonuclear bombs.

Looks like there are three different areas for "most amazing": visually dramatic, theoretically subtly dramatic, and household use. High energy pumped lasers, 0K cooling, and pointers, seem to be most mentioned. Runners up include precision miniature engraving, 3D imaging, and optical disc heads.

So I would update my choice on the criterion: what use of lasers has most affected my life? Has to be laser-driven multi-mode optical fibers. CD/DVD's are transitional technology, pretty soon to be replaced by Internet delivery and flash memory. Holograms are still really laboratory amusement (although display tech may be getting down to the resolution where graphics chips could present holograms on them instead of traditional images). But the data delivery remains, and that is fastest (and only economical option for cross-country) via fiber datacomms, and that takes solid state lasers. And fiber bandwidth to the home will always exceed wireless. Spatial multiplexing just wins.

And what idiot called that "WiFi' anyway? Totally wrong meaning. Makes me think of "HiFi", i.e. audiophile listening quality, not delivery medium. Gah!

By Gray Gaffer (not verified) on 27 Jan 2010 #permalink

Lasers in high precision positioning (to a few nanometers):
- Interferometric techniques in electron beam lithography systems (and LIGO, of course)
- Bouncing a fat laser spot off the back of a shiny cantilever and using it to measure atomic level topography in an atomic force microscope