808nm laser visibility

[Trevor]

And you guys simply can´t stop. I´t was not my intention to educate you and never said something like "lololol ur rong nd you're're coutnry scuks!!!111" Again. Where did i say that? Point me to it.

This:

It also isn´t worth arguing over 80% of the US population is beliving Kanada is an island. Tell me why it dosn´t wounder me all who gave me a bad reputation so far are living in the US? Is this all all of your 80% can? Building guns, shooting first and then asking its an enemy or friend and making war?

You dug your heels in and decided to start throwing insults. Good job.

Actually there is nothing specific to find about IR laserdiodes. But there is enough material telling in general about noise within a bandwith around the specific weavelenght that is produced by laserdiodes caused by impurities. There is enough info about the more impurities in laserdiode the more noise it produces and how they are trying to aviod it. You will find info about the bandwith of the noise and so on.

So... nothing specific on IR diodes emitting light far into the visible spectrum. A simple "no" would have sufficed.

We're well aware that laser diodes have a wider linewidth than something like a gas laser.

So, why don't you look at the material that Bluefan posted that demonstrates what we've been trying to tell you? 808nm is barely visible. Deal with it.

-Trevor

 

[Trevor]

That´s the first really usfull info. So ok. If i was wrong about the range then I admit i was wrong. No big deal. However this doesn´t imply laserdiodes do not have some sort of noise that can range up to the visible area.

Hell, I'll give you an 808nm LD to test on your spectrometer to show you it doesn't emit in the visible area...

-Trevor

 

[Cyparagon]

You will find info about the bandwith of the noise and so on.

Where? Most of the links you posted were off topic. I only saw "A professor Denis Deppe of the University of Central Florida has invented a new small laser diode that has fewer impurities in it. This brings several benefits. Firstly, the emitted light has a single wavelength" No specifics about linewidth or noise.

And I'm sure you'll find if even a HeNe (technically) has multiple wavelengths, it is impossible to have only one. Also, notice they said "fewer impurities," not "no impurities." therefore it cannot be one, but I'll say it again: lasers have wavelengths close enough together that it makes sense to refer to it as one.

 

[Bluefan]

My guess would be that non-semiconductor impurities would behalve like a lattice mismatch would in a double-heterostructure laser diode, it would be an efficient point for non-radiative electron-hole recombination.
If any impurities would cause emission, which I already doubt, it would definately be far below laser threshold and thus be incoherent. Semiconductor lasers are of course made with the fewest impurities, and the very small number of impurities will have a far too low gain to reach the threshold needed for lasing.

 

[honeyx]

Where? Most of the links you posted were off topic. I only saw "A professor Denis Deppe of the University of Central Florida has invented a new small laser diode that has fewer impurities in it. This brings several benefits. Firstly, the emitted light has a single wavelength" No specifics about linewidth or noise.

Thats the point. Fewer impurities resulting in having a laser with just one single wavelength. No specifics about bandwith and noise but the less impurities the less noise obviously with better results.

And I'm sure you'll find if even a HeNe (technically) has multiple wavelengths, it is impossible to have only one. Also, notice they said "fewer impurities," not "no impurities." therefore it cannot be one, but I'll say it again: lasers have wavelengths close enough together that it makes sense to refer to it as one.

Here I agree with you. Even a HeNe has multiple wavelengths but depending on the resonator mirrows just one is amplified.

And whats about impurities. You simply can´t produce a cristal with no impurities at all. Even in a absolute vacuum you will still find some atoms as its impurities.

You dug your heels in and decided to start throwing insults. Good job.

Well dude. You understand this that way. Just because it´s a fact many people in the US a really thinking Kanada is an island, dosn´t mean your country sucks. That´s what you are thinking I must be tninking, but that simply isn´t true. I have friends in the US and already visited your country and i like it. There are a lot of good people. Just don´t like the pistol mentality of some of you.

So... nothing specific on IR diodes emitting light far into the visible spectrum. A simple "no" would have sufficed.

We're well aware that laser diodes have a wider linewidth than something like a gas laser.

So, why don't you look at the material that Bluefan posted that demonstrates what we've been trying to tell you? 808nm is barely visible. Deal with it.

-Trevor

Ok so let us conclude I was wrong. At least Bluefan gave me a acceptable answer i can live with. Didn´t you se my post? So obviously I was looking at the material he posted. So now why are you still digging on it and asking?

I already admitted I was wrong after looking at it. I´m maybe stubborn but finally got the answer i wanted to hear.

However. Noone of you could explain my observation so far i once made, where a defective IR diode was still putting out some sort of visible "red" to my eyes but was completely dark while watching with a IR filtered nightvision at it. This was the reason for me to belive IR can´t be seen at all.

Therefore all the info about impurities making noise, the bandwith of the noise made some sense to explain this.

 

[Trevor]

it´s a fact many people in the US a really thinking Kanada is an island

[citation needed] :shhh:

-Trevor

 

[honeyx]

This was actually in a newspaper i was reading some time ago, so no citation possible exept i could travel back in time and buy the newspaper once more.

But here some funny questions for you

-do u speak german in germany?
-is germany in russia?
-where in USA is germany?
-do u hate me 'cause i'm a jew?
-is it right that the germans have sex in planes?
-is it right that german girls do not shave their legs?
-so all gemran girls have blond hair?
-have u got bathrooms in germany?

And probably the best one

- in america the small kids play cowboys and indians and then the cowboys shoot the indians. Do the german children play Nazis and Jews?

 

[Trevor]

Ah yes... it was in a newspaper. It must be true.

I stand corrected. :crackup:

-Trevor

 

[Cyparagon]

Noone of you could explain my observation so far i once made, where a defective IR diode was still putting out some sort of visible "red" to my eyes but was completely dark while watching with a IR filtered nightvision at it. This was the reason for me to belive IR can´t be seen at all.

There are different filters. You probably used something like this which "can block all visible light under 950 nm." Thus your 808 was rendered "invisible"

 

[honeyx]

Ah yes... it was in a newspaper. It must be true.

I stand corrected. :crackup:

-Trevor

Didn´t say it must be true. It was acutally "Focus" - not just a newspaper but a really trustfull magazine. And by reading those questions above you wounder why?

I myself was once asked by a US American where in Europe is Bagdad? I replied to him with a question too. " You guys are actually making war there and you seriously are asking me where in Europe Bagdad is?"

Sarcasm is the lowest form of wit since its aim is to belittle or hurt someone, and to laugh at their expense; we associate the word "cutting" with it.

There are different filters. You probably used something like this which "can block all visible light under 950 nm." Thus your 808 was rendered "invisible"

Not exactly. The filter is actually a coating on the lenses inside the optics of my Nightvision and not blocking 808nm light. I´m also having a not filtered nightvision that not just amplifing IR light, but am using tie filtered to quick check IR laserdiodes.

 

[Trevor]

Didn´t say it must be true. It was acutally "Focus" - not just a newspaper but a really trustfull magazine. And by reading those questions above you wounder why?

I myself was once asked by a US American where in Europe is Bagdad? I replied to him with a question too. " You guys are actually making war there and you seriously are asking me where in Europe Bagdad is?"

It's funny how you call me out for being sarcastic because it's meant to "belittle," when you're generalizing an entire country for the purpose of insult.

Maybe I should cite the definition of "hypocrisy."

No, no. That would make you look bad, and you're doing a fine job of that by yourself. That would just be mean.

-Trevor

 

[Morgan]

I don't like trolling, (as some will be aware!), and hate to side with someone that may be guilty of it but I have to post this...

Visible red light from 940nm led laser

The whole page is sort of interesting, certainly relevant, but it's the last post that is telling.

From Roithner Lasers, unequivocally a respectable name, had a batch of 980nm laser diodes emitting at 670nm as well. I'm not saying the red light seen from 808nm diodes is a spurious emission of a very separate wavelength , which seems to be the argument, but it certainly seems to show it is possible for an IR laser diode to emit a visible line as well.

I hope this doesn't kick the argument into another gear; just food for thought as to how someone may find it easy to believe that 808s emit visible wavelengths too. Other LD do it so why not 808s?

M

 

[honeyx]

It's funny how you call me out for being sarcastic because it's meant to "belittle," when you're generalizing an entire country for the purpose of insult.

Maybe I should cite the definition of "hypocrisy."

No, no. That would make you look bad, and you're doing a fine job of that by yourself. That would just be mean.

-Trevor

Yes indeed. I must be called YOU, just because i quoted something about sarcasm not pointing to anyone. I was also sarcastic in the heat of defence. Sure and didn´t say anywhere I wasn´t. But i calmed down, you obviously not. You dude must have big problems taking everything personal thinking everything is directed towards you. Your patriotism is at the wrong place. I´m not generalizing an entire coutry. Read what I´ve said before, before you are making such conclusions. I´ve said there are a lot good people. Like in every country you will find good and bad people.

Tell me. Why did I knew you will strike back when i quote something about sarcasm? It´s because i figured out how you are thinking. So calm down dude.

 

[Trevor]

I believe the term you're looking for is 'passive aggression.'

Also, from Morgan's link:

I'm surprised Sam didn't pick up on this.

You're looking directly at the laser emission with your eye, right?

The human eye's response doesn't just stop cold at some wavelength.
You can actually see into the infrared a tiny bit. Some people can
see further than others. The eye will interpret this IR light as
red, but not very dimly.

There is a danger to you looking at this 904nm laser directly. Because
the eye is so insensitive to that frequency it doesn't appear bright,
but in fact there is a lot of laser radiation entering your eye.

I believe you said in your original post that it was 50mw? That is
definately bright enough to have a real danger of causing eye damage.

I recommend reading the following sections from Sam's LaserFAQ:

Laser Visibility and Color
http://repairfaq.ece.drexel.edu/sam/laserioi.htm#ioilvs

Laser Safety
http://repairfaq.ece.drexel.edu/sam/lasersaf.htm#saftoc

Brian

-Trevor

 

[honeyx]

Maybe too

Btw, i saw what you have written before you edited it and removed this part. I´m not german, just living here for more than 30 years and you would probably wounder where my parents come from. But now let´s stop this flame war. It´s totally out of topic.

 

[lasersbee]

Maybe too

Btw, i saw what you have written before you edited it and removed this part. I´m not german, just living here for more than 30 years and you would probably wounder where my parents come from. But now let´s stop this flame war. It´s totally out of topic.

If you have lived in Germany for 30 years... would you
not have your German citizenship...:thinking:

Jerry