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White semiconductor lasers? Please explain.


APEX1

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I cant wait to see what kind of power this thing can put out! Also if he were to drop by and give us a lecture on it,? I would be for ever grateful hahahah! :worthy:
 

DrSid

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Yeah, it is 'just' RGB on single chip. 'Tunable to achieve all colors' isn't the same as 'tunable to achieve all wavelengths'. Color is what humans perceive.
 

Encap

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Yeah, it is 'just' RGB on single chip. 'Tunable to achieve all colors' isn't the same as 'tunable to achieve all wavelengths'. Color is what humans perceive.
And different colors are what, in terms of wavelength? :pop:

'just' ?? ---don't be so quick to say that --it is what it is---
Read the supplemental fact sheet, here http://www.nature.com/nnano/journal/vaop/ncurrent/extref/nnano.2015.149-s1.pdf and see in more detail 'just' what it actually is and isn't. Is very interesting--at least I think so as is what the effort is about---direction it is going.


:can:
 
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DrSid

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And different colors are what ? in terms of wavelength? :pop:

'just' ?? ---don't be so quick to say that --it is what it is---
Rread the suplemental fact sheet , here http://www.nature.com/nnano/journal/vaop/ncurrent/extref/nnano.2015.149-s1.pdf and see in more detail 'just' what it actually is and isn't. Is very interesting--at least I think so as is what the effort is about---directon it is going.


:can:
Again .. color is what human perceive .. wavelength (or better, spectrum) is what source radiates.

For example (perception of) yellow can be obtained by either single 'yellow' wavelength .. or by combining two wavelengths .. which would be perceived as red or green, if the were alone.

Also you have spectral colors, which can be obtained from single wavelength, like red, yellow, green, blue .. and then you have colors outside spectrum. Like violets, which can only be obtained by combination of red and blue.

You can say every wavelength has it's color. But not every color has it's wavelength.

And so you can argue that 'tunable to produce all colors' can apply to RGB system. But sure, it is pretty confusing statement.
 

Encap

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Again .. color is what human perceive .. wavelength (or better, spectrum) is what source radiates.

For example (perception of) yellow can be obtained by either single 'yellow' wavelength .. or by combining two wavelengths .. which would be perceived as red or green, if the were alone.

Also you have spectral colors, which can be obtained from single wavelength, like red, yellow, green, blue .. and then you have colors outside spectrum. Like violets, which can only be obtained by combination of red and blue.

And so you can argue that 'tunable to produce all colors' can apply to RGB system. But sure, it is pretty confusing statement.
Maybe am not understanding what you are saying or perhaps something doesn't really translate well from Czech to English.
Maybe what you are telling is a simoplified version they teach Czech kids in school because it is simple and easy to understand---the same as like in USA schools when they teach kids "white" is the entire visible spectrum combined--and that is all they say about it because it is simple and easy grasp regardless of how incomplete and lacking that tiny bit of knowledge of the subject is---something is better than nothing so they imagine.

Anyway what you are saying doesn't feel correct--doesn't come across as even close to correct--- at best clear as mud . I will give it some thought and post back here something for you to consider.
_________________________________________________________________________________________________________________

Update: OK something for you to consider.

A light's color is always dependent on its wavelength but only if the light is moving through one medium, such as air or glass or diamond or whatever medium you choose. Wavelength varies with the speed of light, which varies with the medium. The speed of light is about 0.03% slower in air than in vacuum for example.

If the color of the light always was dependent upon its wavelength, then its color would change when it enters a medium with a different index of refraction but interestingly, it does not. It remains the same!


:can:
 
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DrSid

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Maybe am not understanding what you are saying or perhaps something doesn't really translate well from Czech to English.
Maybe what you are telling is a simoplified version they teach Czech kids in school because it is simple and easy to understand---the same as like in USA schools when they teach kids "white" is the entire visible spectrum combined--and that is all they say about it because it is simple and easy grasp regardless of how incomplete and lacking that tiny bit of knowledge of the subject is---something is better than nothing so they imagine.

Anyway what you are saying doesn't feel correct--doesn't come across as even close to correct--- at best clear as mud . I will give it some thought and post back here something for you to consider.
_________________________________________________________________________________________________________________

Update: OK something for you to consider.

A light's color is always dependent on its wavelength but only if the light is moving through one medium, such as air or glass or diamond or whatever medium you choose. Wavelength varies with the speed of light, which varies with the medium. The speed of light is about 0.03% slower in air than in vacuum for example.

If the color of the light always was dependent upon its wavelength, then its color would change when it enters a medium with a different index of refraction but interestingly, it does not. It remains the same!


:can:
The most important thing I'd like to communicate is that color isn't the same thing as wavelength, and this statement:

Every wavelength has it's color. But not every color has it's wavelength.

Do you agree with that ?
 
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Encap

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The most important thing I'd like to communicate is that color isn't the same thing as wavelength, and this statement:

Every wavelength has it's color. But not every color has it's wavelength.

Do you agree with that ?
Close but, no, not really--not clearly anyway.

Simple test of what I am saying/meaning, is to see if the red color of an object appears the same in different media .

Equipment needed: All that is needed is a glass filled with water and a 700nm red straw or could be a 700nm laser.

Procedures:
Notice how red the straw looks in the air.

Place the straw on the other side of the glass of water and view it through the water and the glass; the color will not change.

Then immerse the straw in the water and look at it from above, directly into the water,
and then through the side of the glass. The redness of the straw will be the same, no matter how you view it,
even though the wavelength of the red light is changing as it goes from one medium to another.

The index of refraction of water is about 1.33, so the wavelength of the red light passing through the glass of water would be 700 nm ÷ 1.33 or 526nm which is a shade of green in air. So we have 700nm red and 526nm wavelength light stimulating the human visual system and they are both the same red color.

Maybe we are saying same thing different ways and if so, it was not clear to me that was what you were meaning to say.
 
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Mattronium

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Close but, no, not really--not clearly anyway.

Simple test of what I am saying/meaning, is to see if the red color of an object appears the same in different media . All that is needed is a glass filled with water and a 700nm red straw.
Procedures:
Notice how red the straw looks in the air.
Place the straw on the other side of the glass of water and view it through the water and the glass; the color will not change.
Then immerse the straw in the water and look at it from above, directly into the water, and then through the side of the glass.
The redness of the straw will be the same, no matter how you view it, even though the wavelength of the red light is changing as it goes from one medium to another.

The index of refraction of water is about 1.33, so the wavelength of the red light passing through the glass of water would be 700 nm ÷ 1.33 or 526nm which is a shade of green in air. So we have 700nm red and 526nm wavelength light hitting eye and they are both the same red color.

Maybe we are saying same thing different ways and if so, it was not clear to me that was what you were meaning to say.
Hmmm, well, ouhh, no. :D Because the "526nm photons" turn back into 700nm when they leave the glass.

For light, the frequency is "conserved" when going from medium to medium, the change in wavelength is just to accommodate the frequency staying the same while the "velocity" changes.

So, while a 700nm (in air) photon may be 526nm (in glass) it will still be the same energy and frequency when it hits our eye. Generally when we say any wavelength, it is assumed the the it is the wavelength for air (or maybe vacuum).



EDIT: DrSid, I think I understand what you are trying to say, although technically "Every wavelength has it's color." is not correct because many wavelengths in the electromagnetic spectrum aren't visible, and thus have no "color". But I do think that we can say that "Every (visible) wavelength has it's color." Disregarding what we call the color, it still is. "But not every color has it's wavelength." Correct :), like magenta, "computer" yellow (red + green pixels) , or even white.


Thanks for pointing out the confusion with the statement "'tunable to produce all colors".
Although, if they can produce Red, Green and Blue "easily" with their method they might as well do yellow too.:D
 
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Encap

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Hmmm, well, ouhh, no. :D Because the "526nm photons" turn back into 700nm when they leave the glass.

Opps not so fast----you're getting warmer but can you be more species specific?
I am having trouble understanding what you mean?

Do you mean when the straw is in the glass of water the red color looks red because the 526nm turns to 700nm upon exiting the glass so all we see is 700nm wavelength even though the wavelength became 526nm in the water /glass??

Maybe another expanded macro-example is needed.
Equipment needed:
Swimming pool and very attractive women in 700nm red bikini.
Procedure:
Study woman's red bikini whilist she is standing next to the pool.
Watch her jump into the pool. observe that bikini submerged is the same 700nm red as it was when she was not in the water.
Dive into the pool and while head is full submerged, open eyes underwater and observe that the portion of the woman's bikini that is submerged is the same still 700nm red as when she was not in the water.
Come up for air and closely observe the submerged and not submerged parts of the woman's bikini are both the same 700nm red color.
Both woman and you get out of pool--observe that wet red bikini in air is the same 700nm red color it was while your eyes were underwater and observing the red bikini from ubderwater underwater and that bikini is same 700nm color underwater as it is on land in air.

We know from the straw and glass of water example that the index of refraction of water is about 1.33, so the 700nm wavelength of the red bikini underwater passing through water to your eyes, also under water, is 1.33/700nm or 526nm--yet the bikini is still the same 700nm red--same 700nm red we observe when the bikini and eyes looking at it are in open air, not in or under the water.

What does this tell ??



:can:
 
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DrSid

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EDIT: DrSid, I think I understand what you are trying to say, although technically "Every wavelength has it's color." is not correct because many wavelengths in the electromagnetic spectrum aren't visible, and thus have no "color". But I do think that we can say that "Every (visible) wavelength has it's color." Disregarding what we call the color, it still is. "But not every color has it's wavelength." Correct :), like magenta, "computer" yellow (red + green pixels) , or even white.
Yeah, true .. but then .. black is color too, right ? Soo .. :beer:
 
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Yeah, in the water, the wavelenght changes to 526nm. However, in our eye, which is always the same medium, the 526nm gets changed into 700nm again (or into whatever the difference between the water and eye may be). However, you will always end up with the same wavelength in your eye, regardless of the medium the light has travelled in.
 
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We know from the straw and glass of water example that the index of refraction of water is about 1.33, so the 700nm wavelength of the red bikini under water passing through water to your eyes also under water is 1.33/700nm or 526nm--yet the bikini is still the same 700nm red--same 700nm red we observe when the bikini and eyes looking at it are in open air, not in or under the water.

What does this tell

The red bikini example helped explain a few things. Funny how I studied that example more thoroughly. :)
 

Encap

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Yeah, true .. but then .. black is color too, right ? Soo .. :beer:

Yes, it is.

Black is the darkest color, the result of the absence of or complete absorption of light.


:can:
 
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Encap

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We know from the straw and glass of water example that the index of refraction of water is about 1.33, so the 700nm wavelength of the red bikini under water passing through water to your eyes also under water is 1.33/700nm or 526nm--yet the bikini is still the same 700nm red--same 700nm red we observe when the bikini and eyes looking at it are in open air, not in or under the water.

What does this tell

The red bikini example helped explain a few things. Funny how I studied that example more thoroughly. :)
I was going to include the 700nm flipflps, 700nm lipstick, 700nm finger and toe nail polish, 700nm beach bag, 700nm swim fins, 700nm beach towel and so on but decided red bikini was enough, not wanting everyone to get side tracked.....:crackup:
 
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Mattronium

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I was going to include the 700nm flipflps, 700nm lipstick, 700nm finger and toe nail polish, 700nm beach bag, 700nm swim fins, 700nm beach towel and so on but decided red bikini was enough, not wanting everyone to get side tracked.....:crackup:
:tinfoil: And don't forget the example with the 700nm laser!!!:tinfoil:
 




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