Homebrew PCBs

Interesting thought:  If the laser focal point is not needed to very short,
the required mirror curvature is very slight.  It would be easy to bend a
plastic front surface mirror, maybe even a thin glass one. 

It is easier to bend it into a convex shape so the narrow laser beam section
could be expanded to match the wide section and then focused normally.

 

To get a as clean beam as possible I have done the opposite to the beam
expander:

Using microscope objectives, the beam is focused on a very small pin hole.
Any secondary beams or distortions does not get through the pin hole.  The
beam is collimated afterwards with a matching second objective.

 

High rigidity mounting and accurate alignment is required.

Bertho

From:  Cristian  Sent: Monday, November 18, 2013 08:05



At 12:11 PM 18-11-13, you wrote:
>
>
>I do not think you want to use an aperture to get a round beam since 
>it will waste power.

Expander-round aperture-focusing is the easy way for an amateur.

> As you suggested, cylindrical lenses will allow you to selectively 
> focus X & Y independently.
>
>Mirrors curved in one plane will also work.
>
>Bertho

Curved mirror will do the job, but I think is hard to find.
If you know a cheap 'one piece' producer, let me know, please.
I'd like to round-up a red laser.
Cristian

>
>To get a as clean beam as possible I have done the opposite to the 
>beam expander:
>
>Using microscope objectives, the beam is focused on a very small pin 
>hole.  Any secondary beams or distortions does not get through the 
>pin hole.  The beam is collimated afterwards with a matching second objective.

Your solution is the same as with an expander: the pin hole has to be 
of 0.06mm diameter (the smallest beam dimension) and you will loose 
the same amount from the perpendicular dimension
as in the expander variant.
Try the led version, it is near square, and the laser's coherency is of no use.
Cristian