Dichroic colour mixing

Well Finally , I received my Dichro for combining red and green. So here is a Mini review to explain exactly what it is and how it works.

It is a small piece of optical glass , that will transmit a certain wavelength of light, yet reflect another. It is a key component in all pro laser scanners, to take 2 beams of different colours to mix and make another colour.

Typically there are 2 different types of Dichros commonly used for visual lasers. The first and most common is the dichro used to combine red and green to make yellow, and the second is the dichro that can use blue laser light to produce the 7 major colours, or even White light (when used in combination with the first Dichro)

I recently purchased a red / Green Dichro from Ebay and in theory can reproduce any colour in between 650nm - 532nm (red, Orange, yellow and green) .

Once the colours are mixed its important to know that it looses a quality that makes it a laser beam. that is coherence , (it will always be a mix of 2 colours and not a new colour).

The red / Green Dichro works like this: The glass will transmit the green while reflecting the red, so with careful positioning of the lens and both lasers, it is possible to simulate both beams coming from the same origin.

here is a schematic to explain what I mean.

This will be a multi post topic, so stay tuned

Jason.

The Lasers.

To make a perfect yellow requires 4 times red to 1 times green (650nm : 532nm) For this experiment , I am using a Pulsar 125 (for the red) and a CNI 35mw (for the green) The green is fully variable in power from 0mw to its max. at max power it will destroy balloons at 6ft and cut black electrical tape. It will also sting the hell out of the back of your hand(so I am guessing it is over 50mw)

being Variable power allows me to adjust the colour over the baseline 650nm Pulsar.

Here is the bare Dichro.

Jason

The Dichro.

A lens or a mirror?

Well its both really, It will transmit green light and reflect red, in fact it seems to be more effecient as a red reflector than a green transmitter.

Have a look. The green is not totally transmitted

Jason

sweet!!! post some pics once you get a yellow beam!

To show you how the red reflects have a look at the camera flash reflecting off the red facet

Jason

Now for the fun part: the mixing

Well the beams are very hard to line up properly and the true colour only exists down the line of the green, as the beam diameter of the pulsar is so wide, but once you get them lined up, the effect is awesome.

Here is full power red with very little green (635nm effect)

Jason

Orange

Jason

My camera is not the best , but this is 200mw+ of yellow (the true colour of the beam can be seen through the lens )

Dichros are a lot of fun and are available from ebay for about £15 ($30)

Best wishes.

Jason

yellow

My next plan is to try and direct the beam into my XY scanner and make a basic tunnel

Jason

Well this experiment is not quite going to plan It would appear that especially when trying to scan a mixed beam, any tiny error in allignement becomes very apparant. I think I need an optics table as opposed to balancing the lasers and optics on books and padding :-[.
But this is my first real attempt, and I am learning more and more.

here are a few more pics.

jason

A Tunnel that is not quite mixed

Although not quite mixed it does have a very nice effect in some fog

Jason

Actually, that looks pretty cool like that - you see a faint reddish glow, lots of green and some yellow ! VERY NICE !!!

The same effect with the green turned way down , producing Amber

Jason

Green at full power, this combined beam is kind of a lime green and is Probably over 200 mw

Jason

Finally a yellow Spiro, if you look carefully you will see that the red and green are not lined up. but learning everytime I try.

This is the end of my mini review on Dichro mixing,

Hope you enjoyed it.

Jason

Sweet scanner setup - is that still that little one you bought for like $40.00 ???