Dorky Poll: Favorite Wavelength

What if your favorite colour isn't given by any single wavelength?

This is a question asked by a known goofball theorist in my department at everybody's thesis defense.

I'm building a non-collinear optical parametric amplifier in the blue which is turning out to be slightly trickier than initially thought. Given how much I think about it these days, I'm going to have to say the colour most on my mind is 480nm.

A close second, the fluorescence produced by business cards (most have pigments in them that are excellent for visualizing UV beams) using 257nm light is really stunning.

There are several easy wavelengths that come to mind that are common in the laser-using fields:
He-Ne Red: 632.8nm
Doubled-Nd:YAG green: 532nm
Tripled-Nd:YAG UV: 355nm
Quadrupled-Nd:YAG really UV: 266nm

This one's easy for me: 557.7 nm. That's the wavelength of the green in the aurora borealis, and it's due to the "forbidden" 1S->1D transition in atomic oxygen.

Runners up: 630.0 nm (one of the doublet for the 1D->3P transition in atomic oxygen) and 427.8 nm (which is due to a transition in N2). Both also occur in the aurora borealis.

I knew the wavelengths offhand. I had to look up the precise transitions involved.

When I first started in nitride seminconductors, our products were 470 nm, 505 nm, and 525 nm; the first of the three was always the easiest and most reliable, but the last was always the prettiest if you got it working right. (The middle wavelength is the offical spec for green traffic lights, if you're interested.)

Now I've moved on to AlGaN emitters though, so the Deep UV of 270 nm is my favorite at the moment.

(Atomic transitions? I think in bandgaps. Let the guys doing PL figure out what lasers they need to excite my samples.)

What if your favorite colour isn't given by any single wavelength?

Then you're not dorky enough for this poll.

i always thought a 568 nm laser would be cool.

Well, no atomic transitions for mine, but they are 410nm and 532nm as those are the wavelengths of the two diode lasers I am using in my research.

1.05 mm. It's the color of the Big Bang. (Although it helps to have microwave eyes.)

Another commenter beat me to it.
Doubled-Nd:YAG green: 532nm

514.5 nm
We had a 20-watt argon-ion laser in undergrad. Very pretty, but very dangerous. I briefly snagged my arm in the beam when at full power (we were pumping a Ti-Saph laser), not a fun experience.

I like the color of an Ar-ion laser, which I think is 514. Its a very pretty blue-green.

I also like the Rb-87 D2 line, where it is easy to look at hyperfine structure using a cheap diode laser. It isn't strictly in the human visible range, but even with an etalon narrowed spectrum, you can see a bit of deep red if your eyes are good.

21 cm, baby!

Atomic hydrogen spin-flip transition.

(Sean Carroll actually beat me to the peak of the CMB one)

Balmer! (The hydrogen line, not the microsoft ape-man).

Melting point capillary, teensy bit of iodine, flame seal. Hit with a green laser pointer. You atomic guys miss all the fun of vibronic transitions.

http://home.sou.edu/%7Echapman/ch445/i2uvvis.gif

I'm afraid my favorite color is black. That would be the absence of any wavelengths?

Favourite colour? M2Ia, the spectral type of the Garnet Star.

0.385625 angstroms. That's the 32 keV gamma ray from the decay of Krypton-83m.

560 ± 190 nm.

(Whaddaya mean that isn't a single wavelength?)

Your poll is insufficiently dorky: the answer should be in wavenumbers!

P.S. 23499 cm^-1.

5 um to 10 um. It's a small band in the mid-IR that's just Chock-Full of roto-vibrational transitions. You can identify pretty much any molecule with an IR absorption or Raman scattering spectrum over this range.
I know it's over 15x longer than the entire visible spectrum, but it's small in the scale of the IR spectrum.

If I have to pick a single color I will go with 1500 nm. This is the peak of the black body spectrum at ~2000 K -- the maximum temperature of most organic combustion (wood burning fires). This is the color of HOT.

1064 nm. Optical trapping beam!

1) 214.5 nm (deep UV, sorry), S to P3/2 transition in cadmium ion (singly ionized)

2) 396.8 nm, S to P1/2 transition in calcium ion (singly ionized)

As an Amateur Radio Operator, my current favorite "color" is at 40 Meters wavelength. I'm also fond of 2M and 700 cm as well.

Hey, my antennas "see" them perfectly well!

511 MeV. ;-)

My favorite colour is beyond any scale ;)

10^18 Hz. It's the color I see whenever I end up in the hospital after crashing my bike.

@25:

Did you hear about the antennas that got married? The wedding didn't go so well, but the reception was great. :-)

I just painted my house sodium yellow (589.0 and 589.6 nm), does that count?

@26

David, do you mean 511 keV (electron mass)?

I'm partial to around 2 microns, since it's in that wavelength that the Milky Way is most clearly an edge-on spiral galaxy...

Well, I've always been quite fond of wearing clothes in tones of the D line transmission for sodium.

And although it doesn't suit me to wear it, the second line of the Balmer series of hydrogen is a lovely colour. You can see this shade in the sky some times just around sunset.

Mine is 485, the excitation wavelength of FITC.

193nm - the deep-UV laser used for deep-submicron CMOS photolithography. I believe it's argon fluoride.

My chip designs are printed with it, so I can't help but be partial to it.

My favorite color has no wavelength, for it is an absence, not a presence.

3.26 cm!
Without that one, all the other wavelengths are just guesses.

4.5 um, from the 4I9/2 to 4I11/2 transition of erbium. I've spent a distrurbing portion of my professional life worried about that transition.

I'm surprised how long it took for someone to mention the Sodium D line(s), 589 nm. I knew a professor who called sodium "the people's atom". Hydrogen was for theorists and rich kids who could afford UV lasers and rf discharges. But it's true that that was in the day's when Rhodamine 6g was THE laser dye. Still, I think Art Schawlow would have agreed.

I knew a professor who called sodium "the people's atom". Hydrogen was for theorists and rich kids who could afford UV lasers and rf discharges. But it's true that that was in the day's when Rhodamine 6g was THE laser dye. Still, I think Art Schawlow would have agreed.

More recently, I've heard rubidium referred to as "God's atom" (I think attributed to Eric Cornell), because it has such convenient properties for BEC work. 780nm is a pretty good wavelength, too.

Spent some time studying the H Balmer lines emitted by close binary stars. The H-beta n=4-2 transition (4865 A) was my favourite. Not very exotic but solid and dependable.

I like Van Morrison's original version best.

435.833 nm, the indigo mercury line

I've been doing an awful lot of HPLC at 200 and 205 nm these days. The ACN needs to be really clean for that.

555nm - peak of the human photopic spectral sensitivity function (Vλ)

I'm with the (other) ham - down around 1m is where the pulsars get interesting.

I'm with the (other) ham - down around 1m is where the pulsars get interesting.

Spent some time studying the H Balmer lines emitted by close binary stars. The H-beta n=4-2 transition (4865 A) was my favourite. Not very exotic but solid and dependable.
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