White Laser (NOT RGB)

[Philosopher]

Sorry about shitposting, but while reading my own thread on BMW headlights I realized the patent I found is actually of a white laser, what Hu suggests in his patent is using magenta phosphor filter with the green laser, and a result is a white laser, add a diffuser? - and you have a car headlight

PATENT US9328887 B2 - by Darwin Hu granted patent in 2016!

Techniques related to generating daylight-like light from green laser and magenta phosphor are disclosed. Such light may be used in headlights of vehicles. The daylight-like light generated from green laser and filtered through magenta phosphor is almost white or substantially white. The white laser is generated from green laser that is filtered through magenta phosphor. The green laser is well known for producing the highest perceived intensity among all colored lasers with equal or similarly provided energy and is low to obtain in cost.

Claim:

I claim:
An apparatus comprising:
a laser source to generate a green laser light;
magenta phosphor provided to filter the green laser light to generate a white laser light, wherein the magenta phosphor is produced by mixing two different types of phosphor in a predefined ratio; and
an optical diffuser to diffuse the white laser light to produce white light beams.

:drool:

Inventor made a mistake, here is a quick fix

 

[Sta]

Unfortunately, this isn't producing coherent white light. A phosphor necessarily diffuses the laser light; it cannot preserve the direction. It is possible that the patent is incorrect; this should not be possible.

 

[Philosopher]

I don't know how the HEX codes are derived, but seems like the patent author simply experimented with HEX, when you mix green lasers #00FF00 with the opposite #FF00FF (magenta) this is what you end up with

 

[Sta]

I don't know how the HEX codes are derived, but seems like the patent author simply experimented with HEX, when you mix green lasers #00FF00 with the opposite #FF00FF (magenta) this is what you end up with

Hex codes are derived from RGB. The difference with the phosphors is that they necessarily disrupt coherence. You have green laser light, which gets converted to green laser light + magenta normal light. The diffuser then blends the two. At no point do you have actual white laser light.

 

[Philosopher]

Unfortunately, this isn't producing coherent white light. A phosphor necessarily diffuses the laser light; it cannot preserve the direction. It is possible that the patent is incorrect; this should not be possible.

I see what you are saying, however my understanding is - the phosphorus magenta filter is placed before the lenses, analogous I suppose to the way green laser operates - we know green lasers are not diodes, they use the crystal to convert IR light into green, this - isn't excited crystals, but its still worth investigating IMO - in this case phosphorus is doing the job the crystal would in the IR diode to make green laser

 

[Sta]

I see what you are saying, however my understanding is - the phosphorus magenta filter is placed before the lenses, analogous I suppose to the way green laser operates - we know green lasers are not diodes, they use the crystal to convert IR light into green, this - isn't excited crystals, but its still worth investigating IMO

It's not analogous in any way. The only way to change the color of laser light while keeping it coherent is to use nonlinear optics, i.e. YAG/KTP/etc. crystals. You cannot use a phosphor to change the wavelength AND keep it coherent. The phosphor absorbs the light and re-emits it. Unless the phosphor lases (which it cannot) the re-emitted light will never be laser light.

 

[Philosopher]

Hmm yes, you are 100% correct - as in flashlights have very tiny phosphorus amount which puts out the light in every direction ~<180 degrees, not 1 degree, but for the argument sake, assuming the light output is MUCH MUCH stronger than what LED could push out (considering another claim made by BMW that their setup creates light 100x brighter than LED) if the optics were placed right after the given magenta phosphor mix - it could in turn be a "laser" just like Maxabeam light which produces a 6 inch wide 1 degree beam that travels for miles, just in this case it would be more "lasery"

But i think ill agree the inventor isnt very good at drawing pictures


here's a fix

dont take my word for it lenses wise its been a while

 

[Chrisbee]

Kind of the same thing as these phosphor candles.

http://laserpointerforums.com/f42/introducing-laser-phosphor-candle-88693.html

I have a whole bag of these tips, and they do emit some pretty bright light when used with a 445 laser.

 

[Philosopher]

EXACTLY, only your example is blue, which is known, and this is green.

BMW is using a mirror coated with a thin layer of phosphor (gotta be heat resistant), then the light output would be the whole bag of those candles combined, it it supposed to be SOOOO much brighter than LED's, yet the cats are still in the bag and nobody knows how they do it so efficiently, also makes me wonder if their result is more efficient than HID lights input/output wise

 

[Alaskan]

Great information, wish we had more technical threads like this, I have been wondering if the light remained coherent when shooting a laser into a phosphor for awhile now.

 

[Philosopher]

okay, i don't know if you guys know, but there are many types of "phosphor," or "Lume" as watch addicts call it, I don't know about most of phosphor, but I am into watches and if you are buying a watch these are the options

Old style Zink Sulfide phosphor which doesn't last long, gets dim fast, and is pretty much outphased

New style dialuminum strontium dioxide which glows brighter and longer

NEITHER of these is used in modern LEDs, I would be surprised, because after you shut off your light - the element goes totally black within seconds, thus concluding that what we or wickedlasers play with, is NOT what is supposed to be used.

Maybe if someone has a burnt out yellow LED - they should blast their blue laser into it and see what happens, this is science forum, experiment.

On the green laser topic - the inventors reason to use green laser is due to it being most visible, but im not sure if the energy transfer would be as efficient as from using blue, this would need to be tested too, also, I will try to research how to get a magenta phosphor, i think these guys indeed are using phosphor, if that's the case, more should be research before anyone handles that stuff, its kind of poison

 

[Alaskan]

There was a thread in the forum some time back regarding automobile headlights which used a blue laser to blast a phosphor disk to make a blue tinted white light, I forget which vehicle it was used with, but it was a luxury car. There was some debate whether 405nm or 450nm was used, but I bought a yellow appearing phosphor disk on ebay and illuminated it with 450nm to find the white light it emitted was far brighter when using 450nm.

 

[styropyro]

I see what you are saying, however my understanding is - the phosphorus magenta filter is placed before the lenses, analogous I suppose to the way green laser operates - we know green lasers are not diodes, they use the crystal to convert IR light into green, this - isn't excited crystals, but its still worth investigating IMO - in this case phosphorus is doing the job the crystal would in the IR diode to make green laser

These are very different processes, although they are similar only in that they convert light from one wavelength to another. In a DPSS green laser, that crystal is splicing two photons together to make a photon of twice the energy, and this process keeps the "laser" qualities of the light (it is still polarized and coherent.) This is called a nonlinear optical process. With the phosphor, the light is generated by simple fluorescence, so the phosphor absorbs the light, and remits light with a lower energy. This process does not conserve the laser quality of the light, so it cannot be focused into a nice beam like you can with a laser.

That being said, white lasers do exist. Ar/Kr lasers emit a bunch of different colors over the visible spectrum and it adds up to a white beam. Also there are supercontinuum lasers which are pretty awesome.

 

[diachi]

These are very different processes, although they are similar only in that they convert light from one wavelength to another. In a DPSS green laser, that crystal is splicing two photons together to make a photon of twice the energy, and this process keeps the "laser" qualities of the light (it is still polarized and coherent.) This is called a nonlinear optical process. With the phosphor, the light is generated by simple fluorescence, so the phosphor absorbs the light, and remits light with a lower energy. This process does not conserve the laser quality of the light, so it cannot be focused into a nice beam like you can with a laser.

That being said, white lasers do exist. Ar/Kr lasers emit a bunch of different colors over the visible spectrum and it adds up to a white beam. Also there are supercontinuum lasers which are pretty awesome.

Good example of Ar/Kr emission:

And a couple of full spectrum, white lasers.

 

[CurtisOliver]

Supercontinuum lasers are my favourite white lasers for sure. So expensive however. Would love it if these became affordable. Thorlabs offers a kit for only around £11000.
link

 

[diachi]

Supercontinuum lasers are my favourite white lasers for sure. So expensive however. Would love it if these became affordable. Thorlabs offers a kit for only around £11000.
link

I just found an album on PL with more images of that second setup I posted ... I actually wasn't searching for that, I was just looking through peoples albums, happy coincidence!

True white laser

Turns out it also has the full-res versions.