ML501P73-2, a capless 638nm 5.6mm 500mW Red Laser Diode - Test results.

[CDBEAM]

HAHAHA...Here is what my eyes see !!! BEAM OUT

[planters]

My guess is that as a monochromatic source becomes brighter and brighter the filters that select or route if it is a multi CCD camera are less than 100% efficient and the blue and green channels begin to add into the image and the color displayed becomes white.

[CDBEAM]

My guess is that as a monochromatic source becomes brighter and brighter the filters that select or route if it is a multi CCD camera are less than 100% efficient and the blue and green channels begin to add into the image and the color displayed becomes white.

Mmmmm ...so....the boys back at the lab wanna call this the " Fuzzy TWATT Effect " or...FTE !! I say we let'em !!

BEAM

[steve-o]

O I C . I see the triangular effect has the guys mesmerized.. Twatt did you say? Very astute of you guys to come up with that explanation of the phenomenon .. Thankx you very very mucho ..

[CDBEAM]

A little cartoon....just for you Steve-O..... BEAM

[steve-o]

Gotta love Martin Short doing the super-freak-geek thing .

Warning --thread derailment detected --- beep . beep . beep . ---

[CDBEAM]

HAHAHA....I was just try'in to entertain...."Thread derailment" you say....Yikes...
" I jumped all the TRACKS "...years ago !!! Almost ALL just ignore my " MOST EXCELLENT " humor...
BUT...YA get what ya pay for !!! ( HINT....DONATE to PL and maybe the entertainment 'round here will improve!!! )

Anyway...A pic is worth 1000 words....so....BEAM OUT

[steve-o]

Because the near field dimensions have to be included with the divergence calculations, could you give the raw far field numbers?

Yep, had some time today. 5mm at aperture and 35mm at 77 ft. It looks a little bigger in the pix because of camera ccd saturation I suppose and glare. Cameras don't seem to like the brightness of a laser spot and it freaks them out. I even held up a blue dichro in front of the camera lens to try to filter some of the brightness out ..









I cut the big PCV lens in half today w/ the dremel.. pretty smooth cut eh ?

[planters]

Thanks for the pics. To measure the dimensions of a bright beam sometimes I'll measure the actual beam in dense fog. It is surprisingly easy to identify the edges without blooming. Alternatively, I like your shot of the spot on the 30 mm wide ( and now somewhat shorter) cylinder where the spot looks about 1/6 of the width.

The far field just might be improvable. These cylinders don't have their optical axis perfectly parallel to their rectangular edges and when sitting on a flat surface they can introduce a small amount of uncompensated vertical power. This shows up as a kind of twisting distortion to the far field ( similar to the shape I can see on your card), but is almost impossible to see in the near field. If you very slightly rotate the second (positive) cylinder in the plane normal to the beam the central spot returns to a clean rectangle, BECOMES SMALLER and the most noticeable effect is the appearance of crisp distinct multimode stripes stacked vertically above and below the central spot. The stripes can be easily removed later.

[steve-o]

Thanks for the tips. I did notice that I have to very slightly rotate that lens to get a good perpendicular horzontal line farfield before moving it into the focal point. Looks like I'm going to have to micro shim one end to square it up before gluing into place.