combine beams? Your ideas?

I know there's other threads about beam combiners but do we have any new ideas around here?

I'm interested in attempting something that could be used to combine two beams as precisely as possible, i was thinking a chamber with some internal mirrors... or some other way to trap light and give it only one exit (if it can be done while sustaining a beam).

Seems a challenging but interesting project, i thought of this after finding out i can have good quality mirrors shaped in any way i desire if need be, but can shapes be used to give a precise alignment?

A good example would be using a mirascope sort of mindset or any other clever ideas?

for those who don't know what a mirascope is ---> Doctor Who: Hologram Chamber @ Forbidden Planet

-Paul


EDIT: And may i post this! Hahaha, pretty funny.

"Look at him", "He thinks its really there".... "What an idiot" hahahahahaha

http://www.youtube.com/watch?v=n0ITOR1vZ0c&feature=results_video&playnext=1&list=PLA21538FB2CE252BE

Enjoy

We all use

to combine beams with a different wavelength,nothing else then that.
And your , me or whoelse can only combine 445 532 650 nm ( closeby the nm fact. )

Yes. Dichros or a PBS (polarised beam splitter/combiner) will work.
When you combine the following colors, you get the resultant color if you can line up the beams well enough.
Red + green = yellow
Red + blue = magenta (almost pink)
Blue + green = turquoise
Good luck, combining beams is very difficult.

You can always replace 445nm with 405nm

Ash said:

Good luck, combining beams is very difficult.

Click to expand...

Building a house is difficult but with a good foundation issn't

Dichroic and a Good baseplate.

Combining 3 or more beams is a challenge, however two beams can be combined relatively easily.





combining an Argon and HeNe using a dichro off a broken HeNe i had.

Hmm was about to order the dichros from olike will they work with 445 532 and 650nm?

if you combine two beams of the same wavelenght does the power add up too?

Yes the power is combined but there are losses from the optics, more so if they aren't AR coated. Knife edging or a PBS works for the same wavelength. PBS can do two beams only (oppositely polarised), knife edging is unlimited but the beams get thicker with each you add.

Combining colors is way more fun tho.

you can knife edge with correction optics like my red build or you could also use some 1x setup to bring the beams close then knife edge so they can be very very close.
not super easy but its the only way if you can polarize a beam.

weeba2kv said:

We all use

to combine beams with a different wavelength,nothing else then that.
And your , me or whoelse can only combine 445 532 650 nm ( closeby the nm fact. )

Click to expand...

So this way is got in order to combine colors but also for increasing power? like instead of three different wavelengths I could have this array with three lasers of the same wavelength?
What excactly is knife edging?

(I hope I dont interfere too much with the original threat)

To combine two like wavelengths, you either need to knife-edge them (i.e. putting the dots really close together by using mirrors) or a polarizing beam splitter which will reflect or transmit, based on polarization.

As far as I know diodes differ a little in wavelength but you would still need to polarize? what would happen if i used the color combiner with diodes of the same wavelength?

I saw arrays with knife edging where they had several beams not too close together but a lens at the end focused them and made one beam. wouldnt it also be possible to aim several laser diodes that are close together on this kind of lens to get one really powerful beam?

Are there limitations to how many beams can be put into one or how powerful it can get?
And also: do the lenses overheat if the beam is too powerful?

if you just point a bunch of lasers at the same spot on a lens, they all hit the lens at slightly different angles, and as such, will exit the lens at different angles.

When you knife-edge, all the beams are still parallel. The basic idea is to add a beam parallel to another beam, and as close to it as possible without blocking part of the other beam with the mirror. 8 Diode 445nm Module here's an example. Since you can only combine two beams with a PBS, that limits you to two beams. However, those two beams can be made up of more beams, as long as they are all polarized the same for passing through the cube.

In this example, four diodes are polarized || and knife-edged to combine them into 4 stacked bars, approximating a square.
Four other diodes are also polarized || and knife-edged to combine them into 4 stacked bars, approximating a square.

If you've been paying attention, you'll notice that both beams are polarized the same. If these beams went to the cube as is, they wouldn't combine, because they would both either pass through or reflect. To combine, one beam must pass through, and the other beam must reflect to be overlayed on the first beam. However, if you turned 4 of the diodes to be polarized =, then the knife-edge would result in a long line ---- instead of IIII. Another option would be to use a wave plate. This plate magically (for lack of understanding on my part) rotates the polarization so that it can be combined with the other beam.

So, the || and the = beams are combined at the cube and exit as one beam.

Am I seeing that right? the cube gets the beams from left and up and the combined beam exits down?

But did I get it right that there are lenses that can combine these parellel beams?

When You get the beams to hit the same spot wouldnt it have the same effect as having a combined beam hit it?

I still dont really know what polarisation does to the beam

nikola tesla said:

Am I seeing that right? the cube gets the beams from left and up and the combined beam exits down?

Click to expand...

Yep, this is because one beam is polarized vertically, and one is polarized horizontally. The cube is basically a holder for the specially designed interface between the two halves. This interface behaves differently depending on polarization, so if the beam is polarized one way it will pass straight through, while if the beam is polarized the other way, it will reflect off of that interface like a mirror.

nikola tesla said:

But did I get it right that there are lenses that can combine these parellel beams?

Click to expand...

Kind of. They're not really combined, they are just parallel and arranged really close together using mirrors. Think about if you had a hand mirror and two lasers. You shine one straight, right next to the mirror. The other one you shine onto the mirror right next to where the first laser is passing. Then you adjust the mirror so that both beams are parallel. This way, no matter the distance, they will still make the same sized "dot".

nikola tesla said:

When You get the beams to hit the same spot wouldnt it have the same effect as having a combined beam hit it?

Click to expand...

Almost. When you combine beams using knife edging, the beams aren't on top of each other, they are just really close to each other. If you were to point a bunch of lasers at the same spot, their combined powers would all be converging on a single spot, putting a sum of power on a spot the size of a single laser dot.

nikola tesla said:

I still dont really know what polarisation does to the beam

Click to expand...

It doesn't have any visible qualities, but it is a property of laser light we can take advantage of with special optics like PBS cubes and wave plates. I like to think of light as a wave when I think about polarization. If all the waves are aligned in one direction, i.e. they all are going up and down and up and down, then they are polarized. Polarizing filters take regular light and block any light that isn't polarized. This is the generic graphic for helping to understand polarizing filters:


If you have polarized sunglasses, you may be able to detect the polarization of your diode-based lasers by shining the laser through the polarized glasses and observing the dot changing in intensity as you roll your laser or glasses.