Sodium Chloride Laser Possible? [Answered: Yes]

[the guy]

would it be possible to make a lsaer with sodium chloride as the medium? if so would it be powerful?

[John Cuthber]

Salt is white. It doesn't absorb visible light. That makes it unlikely to emit visible light (I realise red hot salt will glow red, but I don't think that there are any specific transitions involved). Salt is also use for "optics" in infra red work becaue it doesn't absorb IR much. I think it's pretty transparent in the UV too.

I wouldn't say it was impossible to make a salt laser but it's going to be very difficult.

 

Why did you ask?

[the guy]

no idea. i was just thinking and was curious. i find it hard to concentrate when i have an unanswered question in my mind. thankyou.

[Klaynos]

GaAs is grey, you can make lasers from that

 

The question you must ask is can you create a population inversion in the energy levels in any way and maintain it?

[swansont]

There's a saying that anything will lase if you pump it hard enough. They made Jell-o lase. It's an issue of what frequency and the efficiency.

[Sedit]

yes they have made NaCl lasers .

 

@john is has no matter as to weather it absorbs a specific freq but rather weather it emits it when it is excited .

 

" realise red hot salt will glow red, but I don't think that there are any specific transitions involved). "

 

there are specifics. When an element or chemical absorbs enough energy to become excited it releases some when the electrons drop to a lower state and emit a photon in the process what is needed for a laser is population invertion where more electrons are in the upper state then the lower state at any givin time

 

The thinking here seems to be that the mediums color has any dependence on the output wavelenght which isnt really true what matters is what 'orbit' the electrons move from when moving from upper to lower state

 

I could easyly go deaper in this topic if needed but for now yes a NaCl laser can and has been constructed i will get back to you as to the frequency but for now i would have to say it would be in either the yellow band,red or IR. But alas i know it has been done

 

PS: just to put it into perspective one of the strongest 'easy' homemade lasers is the type that i am contructing at the moment it is a CuCl laser. It operates at 600deg c and outputs two bands in the green and yellow range

Edited December 17, 2008 by Sedit
additions and corrections

[swansont]

Of course, Googling on this is an easy way to answer part of the question

 

http://www.iop.org/EJ/abstract/1063-7818/23/1/A06

http://adsabs.harvard.edu/abs/1989PhDT.........6Y

[John Cuthber]

Did you have a look at those 2 papers? Here are a couple of quotes- one from each.

"Abstract. Stable lasing has been obtained on and color centers in additively colored OH:NaCl crystals. "

"This thesis reviews the development of an APM laser based on the NaCl:OH(-) color center laser. "

The thing about materials with colour centres in them is that they

1 are not white

and

2 are not strictly NaCl.

 

It's like calling a ruby laser an Al2O3 laser.

Al2O3 is the matrix that holds the Cr(III)ions , they do the lasing.

[YT2095]

actually this has reminded me of an Idea I have for a possible White beam laser using Red/Green and Blue solid lasing materials as rods whose cross section looks like a 1/3`rd of a pizza slice (120 degree angle I think it would be), and these are put together to form a rod and then fused with an induction heater.

would the middle bit give a white light? or would it just be like 1 giant TV pixel?

 

sorry for the Off Topic sidetrack but the OP has been answered and I didn`t think it warranted a new thread.

[John Cuthber]

Can white light be coherent? (OK,a short enough pulse might have enough uncertainty to have a wide enough bandwidth to count as white.)

[Sedit]

The closet thing i know of to coherent white light is an argon laser doped with Ne if im not mistaken

 

After running though a prism this laser exploads into a messload of frequecys but when combined apear as white light

 

They are a sight to behold when the laser passes out of the prism

 

The Sodium Cloride laser i have seen mention of operates at high temperatures enough to vaporize the salt and then the lasing action takes place in the Na+ Ion

 

Metal vapor lasers are becoming the thing to try in the laser field because many have extreamly high gain.Like the lead vapor laser(Red) or the copper vapor laser(Green/Yellow) which operate 'superradiantly' so mirrors are not needed and may just cause it to blowup if they where used

 

The only differnce between a sodium vapor laser and a NaCl vapor laser would be a duel pulse needed in rapid sucession to ionize the NaCl vapor into Na+ Cl- then another pulse to cause the Na+ to lase

 

All this must be done in a few nanoseconds or less and let me tell ya this isnt no easy task getting a thin enough dielectric for the capacitors so induction is low yet still be able to store the 4k-30k voltage required

[Klaynos]

White to human eye does not nesasarally mean white spectral, especially when you make things lase, take for example tunable lasers, you can change the frequency at which they lase.

 

There are crystals that you can use to create coherent continuous white light beams, but they are not strictly lasers and require pumping from short pulsed (femptosecond) lasers, and are a non-linear frequency conversion system, similar to how THz pulses are made...

[Sedit]

White to human eye does not nesasarally mean white spectral, especially when you make things lase, take for example tunable lasers, you can change the frequency at which they lase.

 

There are crystals that you can use to create coherent continuous white light beams, but they are not strictly lasers and require pumping from short pulsed (femptosecond) lasers, and are a non-linear frequency conversion system, similar to how THz pulses are made...

 

cool thats something i have never heard of. Do you know if they create a continues spectrum or do they just make enough frequencys to apear white like the argon laser does?

 

Tunable lasers dont realy have a very broad band to chose from though. In perspective to normal lasers the band is huge but compared to whilelight there isnt that much change. There still pretty cool though Iv been trying to build one but its being a pain because im having trouble passing the UV pump laser to focus though the dye cell

[Klaynos]

They create a continuous spectrum.

 

I'm not very familiar with them, I've done something similar (but generating a cone) using silica and a femptosecond laser (by accident).

 

I've got access to a tunable laser that will go from about 850 -> 350nm... It's a Ti:Sapphire laser...

[John Cuthber]

If the "NaCl" laser actually uses the Na+ ion then it would probably be easier to use NaI which is more volatile.

[Sedit]

Cu vapor lasers usualy use CuBr if im not mistaken so yeh any salt should work as long as you can vaporize it

 

Thing is i know a little something about lasers and im a little lost how the Cl- or Br ions dont affect lasing

 

Iv heard from alot of differnt places that it is possible to get anymaterial to lase if you can get it in the right conditions, temp,Pulse lenght ,energylevel ect.. so i cant see why there wouldnt be some differnce between Br and Cl but they are used interchangably from what I understand

 

 

"I've got access to a tunable laser that will go from about 850 -> 350nm... It's a Ti:Sapphire laser..."

 

Nice i want one. thats a decent bandwidth for a tunable

Edited December 19, 2008 by Sedit
addition

[Griffon]

I seem to recall that when people were making ultrashort pulsed dye lasers in the 1990s that as they got down to a few femtoseconds the output looked significantly "whiter". I guess this effect may not be so obvious with today's TiS lasers which work in the near infrared.

 

Self focusing intense pulses in air to produce a continuum produces a decidedly white light of course.