laser beam size

[badger1666]

heres what i want to know i have built my first 100mw green projector going to add red laser iknow i will need at least 300mw the one i am looking at on ebay (http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWA:IT&ih=015)
lasershow parts has a 5mm beam, my green laser has a 3mm beam does this size difference cause a problem with colour mixing, also i think some of the beam will spill off the edges of the galvo mirrors would pointing laser at a metal plate with a 4mm hole in it be ok to do and just put up with a slight loss in power

[allthatwhichis]

For any other color I would say go with that brand from them, but for a red, you may want to look at another option and look at a mayxzmodule. The have a two unit set up that produces 400mW+ and may have a better beam spec. If I were going to buy another red my choice would be between a CNI from lasershowparts or a maxyzmodule. The maxyz are also manufactured less than 100 miles away also, so I am a lil biased.

[badger1666]

iam hobby laserist two maxyz units loads of money to much for me i can just about afford the cni red do you think i will get away with using that one

[allthatwhichis]

I understand. That is why I only have one maxyzmodule. That CNi will work fine. Worst case is you lose a little off of your galvo mirrors. Dr Laser has a set up with a similar red where he has a colminator tube or telescope that shrinks the beam. It is similar to the tube phritzer (sp?) has at the end of his 24 diode monster. You could try that.

[badger1666]

thanks
what lens do i need to make colminator tube i am farly new to all this laser stuff

[steve-o]

I've heard that a rifle telescope makes a good collimator.. but that was years ago.. might want to double-check..
Also a beam expander will give smaller beam size at a distance.
Google 'laser beam expander'.

[p1t8ull]

thanks
what lens do i need to make colminator tube i am farly new to all this laser stuff

This is the age old problem with no easy answer, unfortunately.
The laws of physics dictate that if you reduce the beam diameter with a collimator (or beam expander) you increase the divergence by the same factor, and vice versa.

[allthatwhichis]

Don't think you have to shrink your red. You mentioned beam sizes so i thought that was your main inquiry. Like I said, worst case with a wide red is you lose a little off your galvos. When you first realize you enjoy digging this money pit, I think loosing a little off the galvos is the least of your worries. How to pay for that blue was always a tricky one.

[dave]

As Aaron said, the easiest way is to put up with a bit of light hanging over the mirrors. Its not as bad as it sounds...

BTW, the specs on that 660 are pretty god dam awful!! Get a maxyz if you can! You can see the size of the beam in the ebay ad - big!!

[allthatwhichis]

Get a maxyz if you can! You can see the size of the beam in the ebay ad - big!!

Never seen a seller do that! He has a few maxyzs though.