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Help if possible on laser project

paul1598419

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Actually, it would be easier to use one dichro to pass green and reflect red or visa versa. As long as you get the laser's output at the same height above the plane they're on, it is a matter of aligning the single dichro.
 
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jimmy433

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Haha hopefully im smarter than a chimpanzee we will see, i will definitely try this before i use the stronger diodes

i will be combining the lasers in a similar method using 1 dichroic mirror and a gold mirror which will reflect the red diode

as for the electronics part of the project i would like to implement the electronic components and integrated circuits individually just for my own educational purposes and to see the relationships between them.

So far as a basic understanding i will be using some sort of transformer to reduce the power from the outlet to the components, this will supply an appropriate current and voltage to the drivers for the diodes. I will also have heat management system preferably as a heat sink with fans which will manage the heat for both diodes (unsure on the size of the heat sink needed, i understand the conversion efficiency of the diodes directly relate to how much heat is produced which i will work out), i assume i will need voltage regulators for the fans to keep them stable and the output of the diodes will then connect to the optical system i.e. collimating lens, angled mirrors etc..

should these components be able to safely power the device or am i missing some things?

thank you again for taking the time to help me you guys have been a great help
 

paul1598419

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Laser diodes must be current regulated, not voltage regulated. These two diodes will need their own drivers, or a driver board that does the same job as individual current regulators. The current for each must be set in advance of connecting them to the diodes. There is no other way around this. If you didn't know this already, you must research the driving of laser diodes prior to doing anything.
 

CurtisOliver

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I don't understand your choice of diodes Jimmy or your project too much for that matter.
For one, if all you want to do observe the colour then why do you need that much power.
You can get away with using low power single modes that have near matching beam parameters. This will give a much neater and more observable colour combination.
Secondly, using a spectrometer is not going to observe anything but two peaks at the two original wavelengths. The end colour is our own brain mixing the colours not reality.
And lastly, why? What are you going to achieve from this.

If you was to imagine a spectrograph, this is what would happen. With the middle being the combination.
From what I can gather, what you want to see: 400nm¦____/\___/\___/\____ 700nm and what you are going to get: 400nm¦____/\_______/\____700nm
 
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jimmy433

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i understand there will be no visible output, my end task is to just observe the wavelengths once sent through some doped optical fiber which for example may or may not be used as a tool in spectroscopy.

Another example could be depending on the output wavelengths a device which will utilize the absorption spectrum of H2O to target it with energy (a device of such can be used in detecting water and many other applications) sensing tools like this are used on things such as the mars rover and medical devices, but im working on a very basic form of this.

honestly i just need help with the electronics part of it but if you guys are interested i will keep you updated with my progress
 
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CurtisOliver

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Well in this case you need to do some research into the wavelengths you are going to need. Power is not something that seems important. In fact lower power, single mode sounds more what you need.
So you want to see some sort of visual feedback of the individual wavelengths being absorbed differently by the material? For instance if an object absorbs more green then the outcome will look red. :thinking:
 

Encap

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So the two 2.4amp SXD laser drivers i suggested in using wont work?
You can use SXD to drive the NDG7475 --at 2.4A it will output about 1.4W
See--scroll down to see the output at 2.4A: https://sites.google.com/site/dtrlpf/home/diodes/ndg-1w-520nm

The LPC-836 only needs <340mA to output 380mW but is can handle up to about 500mA before the output power begins to drop off.
See: https://www.youtube.com/watch?v=95lw0_iJb6k

You would be much better off with a much higher output red--you might actually be able to make a combined beam that you perceive as yellow even though it is not a yellow wavelength--just a mix of red 660nm and green 520nm stimulating your eye's retina which you would perceive as yellow.
An actual true yellow single wavelength would be in the range between 570nm and 590nm or so.
Don't confuse human visual perception with wavelength which are apples and oranges different concepts. Color is not a physical property, it is merely the brain’s interpretation of different wavelengths of light. Wavelength is not a description of a color you perceive/see. It is term independent of human observation -- a description of electromagnetic radiation.

I don't understand your choice of diodes Jimmy or your project too much for that matter.
For one, if all you want to do observe the colour then why do you need that much power.
You can get away with using low power single modes that have near matching beam parameters. This will give a much neater and more observable colour combination.
Secondly, using a spectrometer is not going to observe anything but two peaks at the two original wavelengths. The end colour is our own brain mixing the colours not reality.
And lastly, why? What are you going to achieve from this.

If you was to imagine a spectrograph, this is what would happen. With the middle being the combination.
From what I can gather, what you want to see: 400nm¦____/\___/\___/\____ 700nm and what you are going to get: 400nm¦____/\_______/\____700nm
Exactly.

I don't understand either,either--neither makes much sense.
Maybe it is some 6th year grade school "science" assignment for 11 to 12 year olds of meaningless busy work put together and demanded by some teacher who does not know what he or she is doing or why.
 
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jimmy433

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i understand i need to do a whole lot of research in the field, iv only just begun looking into laser optics and its awesome. But they were the laser diodes i am to work with for some reason, which i will look into further but i cant change them, i am just concentrating on the electronics part for now.
 

CurtisOliver

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To get yellow out of using a NDG7475 and a LPC-836 you will need to run the LPC at its max and underdrive the NDG.
 

jimmy433

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sorry i dont think i was clear on my part, what i meant by observe was not meant to mean by eye. Mainly measure the emissions, and how much light gets into the fiber.

But i am still learning in the field and only have understood parts of what is expected of my task which is described above.
 
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Encap

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i understand i need to do a whole lot of research in the field, iv only just begun looking into laser optics and its awesome. But they were the laser diodes i am to work with for some reason, which i will look into further but i cant change them, i am just concentrating on the electronics part for now.
If I were you I would have a word with the idiot who assigned this chinese fire drill nonsense device project to you to do. What's next do you have you polish their car or paint a fence or just get them coffee? :crackup:

THe whole thing is an idiotic goose chase and teaches almost nothing that can't be taught 100 better and easier ways.

It is not much of a challenge to buy a 12 V plug into the wall transformer and hook the plus and minus output wires to the + and - pads on the SXD then attach 2 wire to a laser diode is it--if that answers your original posted question.

Anyway good luck doing as you seem to have to do it for whatever reasons.

sorry i dont think i was clear on my part, what i meant by observe was not meant to mean by eye. Mainly measure the emissions, and how much light gets into the fiber.

But i am still learning in the field and only have understood parts of what is expected of my task which is described above.
What fiber? There is not any fiber in or associated with anything you have presented so far.
You never menrioned anything about a fiber. How much light gets into a fiber depends upon how much light you put into the fiber and the capacities/characteristics of the fiber to accept the light you are feeding it.
You are going to need a way to focus and couple whatever combined output-- whatever you put together effectively and efficiently into a fiber if that is what you are looking to do.
Since you are in OZ see LASER DIODE TO FIBER COUPLER: https://www.ozoptics.com/ALLNEW_PDF/DTS0063.pdf.
Call them and maybe they can help you with a way to couple the combined output to a fiber.

Bottom line is that there is not way to advise you unless you state what it is you are actually need to do/achieve, why, and result you are looking to achieve/looking to create.

So far, any advice from LPF members has been a waste of time apparently other than to say get a 12V transformed you can plug in the wall to provide 12V DC to your SXDs--as you could very easily find out "Power with a 6.5V-12V power source capable of 4A+ like two Li-ions in series, 6.5V-12V 4A+ power supply or a variable power supply. Driver requires heatsinking of the 8pin regulator chip on the underside of the driver. Use a thin layer of thermal adhesive to mount it on your main heatsink or host body. Input and output pads are clearly marked for easy installation."
From: https://www.amazon.com/4-5A-Super-X-Drive-Laser-Driver/dp/B01MF67NWC

You are going to need sophisticated test and measurement equipment to determine any of that.
 
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jimmy433

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Thanks the coupler sounds like a good idea.

the drivers i have are 2.4a SXD drivers i cant change them, i also read that these drivers don't require heat sinking but being a newbie i am not certain about this. Also is there a method or a way you guys use to determine how large a heat sink should be? im making a single heat sink to manage both diodes. Thank you again guys you have been a great help
 

hakzaw1

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I cannot see you doing this 'project' and NOT ending in a fail...for ~$ 19 you can buy a plug n play 100mW red and 30 mW 532 green- and you can crudely combine with a simple FS Mirror (knife-edged)--it will not be at all perfect BUT even w/ dichros the different sizes of the beams will make that very difficult--so you would still not get a near perfect yellow.. we see new members all the time wanting to buy a 'crotch rocket motorcycle' but have never even ridden even a MO -PED.. (just a finger of speech)
go with the cheapest so when it DOES fail-- the loss in $$ will be much less.
imho there is more to this story than we are getting...len
 




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