Star pattern

[usakicksass]

I have a RPL-225, 245mw green laser. When I shine the beam close to the corner of a wall but not hitting the wall I see a radial pattern around the main beam on the wall. In this pattern there are light and darker areas. What is unusual(to me) is a small area that comes on and off in green of course. And there are flickers here and there. The laser makes a perfect beam and is too bright to look at reflected so I never noticed this area around the beam.
What is this and why does it happen?

 

[VillageIdiot]

I don't understand... I /r/ a diagram.

 

[climbak]

from the description it sounds like those are just diffraction rings. My argon does the same thing. I may also be that the laser is operating in another TE mode, but I kind of doubt it's that.

 

[usakicksass]

This is a pic of the "pattern". The feature at about 2 o clock kind of flickers on and off sometimes. The radial pattern and the "flicker" of the bright blob at 2 o clock is what I am questioning.

 

[usakicksass]

Sorry about the resolution. This is one of the many items I recovered from the now defunked "egghead.com" return dept. dumpster. The resolution is .75 megapixels, Sony Mavica.

 

[climbak]

hmm, i'm not quite sure what that is. thats not a diffraction ring. It could be something on the lens. I am not sure why it would be flickering though.

 

[f22warzone]

its a dirty lense my dx 200 and alpha lasers use to do that all the time you just have to clean it really good for that to go away. but it wont complety go away

 

[nikokapo]

yeah.....that is just some dirt on your lens, i never bothered to clean my dx30's lens..and it looks worse than that....but wth..

 

[usakicksass]

I need to ask Jack at Optotronics about it, maybe a scheduled 10,000 mile tune up.
I like your glassware f22. I used to have a $15,000 organic chem lab complete with rotovap! I got smart and sold it all. Became a family man

 

[f22warzone]

: ) that’s about a 1/4 of my glass ware in that picture. I’m not too serious into the chemical stuff but it was all a gift from my parents so I find uses for it : )

but ya that is simply just a dirty lense u could fix that yoru self with a lens pen

 

[usakicksass]

I've had the laser for all of 2 weeks. I have been very careful about environmental contaminants. I have a green laser that I "cleaned" many years ago with a q-tip and alcohol. I believe I messed up the acrylic IR filter and now it makes a big blob. I want to be very certain about how I clean my RPL-225. It is still in warranty.

 

[f22warzone]

oh.... we dont use alchol and if you do make shure you tuch a q tip with the alchol on it with another q tip and use that one so its just damp and not wet but that is really the worst way to cleane them.... if your going to clean it just use a lenspen it really is the best then finish it up with a really soft q tip