Laser power on mirror

[Reonarudo]

Hi,
I have 2 galvos with front surface mirrors (dunno if they are coated) and when I point my 300mW 808nm laser to them it came out at ~8mW, does this have to do with the coating of the mirrors? Where or how can I get proper mirrors? Thank you very much.

 

[Benm]

It depends on the kind of mirror you are using. If its an ordinary metal-on-glass type of mirror, no such losses would be expected. Something like 10% power loss from 2 mirrors normal there.

But if your mirrors are dielectric coated ones, they may not be reflective at all any wavelength they weren't intended for - something to do further research on!

 

[Reonarudo]

Thank you very much! I'll check on that.

 

[Reonarudo]

The mirrors are coated with 405nm to 671nm... maybe you can point me to (preferably cheap) mirror provider?

Thank you for the help.

 

[Benm]

I think you'll be able to find some in the buy/sell/trade forums, or just post that you're looking for some FSM's there. Also, there are plenty on ebay, mostly listed as 'front surface mirrors'.

Mirrors with metallic (usually aluminium) coating should work fine for near-IR applications. You can tell the difference between dielectric and metallic mirrors quite easily, as dielectric ones usually have a color sheen to them, that tends to change with the angle your're looking at it.

 

[Jex]

Take apart some old hard drives, the disks are nice first surface mirrors.

 

[alanbrito]

Try ThorLabs, they have economical front surface mirrors.

Thorlabs.com - Economy Front Surface Mirrors

It really depends what you mean by economical, but those seem pretty good and efficienty for your wavelength. We have very high reflectivity IR mirrors that we use with our femtosecond lasers but that is because we need as much power as we can as I work in laser processing of materials.