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Ali Javan passed away last Monday aged 89. Dr. Javan was professor of physics at the Massachusetts Institute of Technology. A native of Iran, later a U.S. citizen, he received a Ph.D. in physics from Columbia University in 1954. While a member of the technical staff of the Bell Telephone...

By blue, do you mean a 488 or 473 nm laser?

I'm late to the party, but first of all inversion is not necessary for lasing. There is "LWI Effect" (lasing without inversion) which works by suppression of absorption, so you actually change the refractive index of a material, making something transparent which would otherwise be heavily...

That's how dye lasers work too, they have the same kind of wavelength-selecting diffraction grating reflector. The tuning is just done by rotating the grating. HR is totally replaced by the grating to make the beam travel exactly along the same direction of incidence. I think ti:sapphire uses...

I believe it's illegal to post batteries, whenever I'm sending a shipment I'm asked whether it contains any batteries.

Oh, it's from where I work at uni. I don't know the brand, but if you search for transmission gratings you should find something similar to this. It replaces the prism in the spectrometer-goniometer arrangement.

Yes, this one had 600 lines/mm, the same kind often used in grating spectrometers.

I don't know if there is a single software that does all that. Maybe if you searched for each one individually that would narrow down the search. I know that there are software that allow you to compute reflectivity of the mirror for an arbitrary number of coating layers (depending on the...

I had no idea mirrorless tubes were so expensive. But why do they have different gas fills?? I know orange mirrors are rare. I haven't looked into it to see if it's doable... but in principal if you deposit thin film wave plates onto each other you get a profile of reflectance vs wavelength...

To my eye 590 is still yellow with a hint of orange, it's certainly yellow relative to 600+ nm. 589 is also a deep hue of yellow, the same colour as the sodium doublets. You can easily confuse one for the other if you don't know what you are looking at.

The line between yellow/orange and orange/red is blurry. It's impossible to say at what exact length yellow turns orange. It makes it even harder given that colour perception is subjective. This isn't b&w; it's a grayish area completely open to personal interpretation.

If I have to pay 2k, I would rather buy a tunable HeNe which has both orange lines (612 and 604). For how much can you get a HeNe tube with Brewster's windows but without any mirrors attached to it?? Because to me it seems you are basically paying ~2k for just the end mirrors. I wonder if it...

I think you 'might' get even better results if instead of 405 nm, you mix 445 or 473 nm with the red. The result would be closer to pink (more of a rosy carmine colour), rather than magenta or purple pink.

Hi RYDorDIE278! I'm from the North Shore in Auckland.

Main advantage is that you can increase the power a lot when the output pulse has a limited duration. It's has a lot of medical applications for instance. It's also used in basic science research, the compressed pulse as short as femtoseconds or attoseconds that's an area right now. But there...

For your LHP, you can probably use Melles Griot LPM 824-065 power supply. I use that to run my 543.5 and 593.9 nm tubes, the latter has approximately the same resonator length as yours so must have similar rating. The only difference is that in your LHP all axial modes are linearly polarized...

Thanks. But I must say that many of the properties you've mentioned (such as impurities, mixture ratio, effective refractive index, pressure, wavelength, etc) are already accounted for in γ(ν). Of course my calculation is not accurate, I was looking for a rough idea as to how small these things...

The label says it's He-Ne, but where is the tube at? What is inside the black box (not the power supply, the other one)? :confused:

To be specific I guess my question concerns the HeNe. I wanted to know the smallest tubes ever made commercially available, as well as the smallest "working" HeNe theoretically possible. Around ~99% reflectivity I get ~4". However, I assumed a lossless medium because I didn't know an...

Re: New Laser Information site I've forgot the name but I believe there is already a wiki that covers most aspects of the lasers and photonics, but it has a scientific and engineering approach rather than hobbyist.