Sweet "Diffraction Grating"!!!

Last night, I was pointing my X100 at a CD(The part which the computer reads the disk: AKA shiny part) and I noticed VERY cool effects made from the reflection! At some spots on the CD, it makes an effect which looks like many rings, like on Saturn, with dots in between the rings. If you point the laser towards the middle of the CD, it makes a Mega Matrix effect. This could save you $$$ the next time you want to pay $20 for a diffraction grating!


I don't know if you guys already know about this, but since I can't find it anywhere on the forum, I decided to post it. Sorry I can't post any pics.


**EDIT** It seems scratched CD's work better than clean ones if you want the "Saturn Ring" effect.

As soon as I read this I got a CD and a DVD and tried it , with a red and a green laser, but I can't get the effect that you described All I get is 2 short lines and multiple dots in between with the DVD and more lines with the CD(I think it depends on the number of layers.

Btw, be very carefull as the different layers reflect the laser at different angles so the reflection off of a CD is less predictable than a simple mirror reflection.

Switch said:

As soon as I read this I got a CD and a DVD and tried it , with a red and a green laser, but I can't get the effect that you described All I get is 2 short lines and multiple dots in between with the DVD and more lines with the CD(I think it depends on the number of layers.

Btw, be very carefull as the different layers reflect the laser at different angles so the reflection off of a CD is less predictable than a simple mirror reflection.

Click to expand...

Yea I'm trying different CD's and DVD's and I indeed get different results from each one. Some CD's work better than others, which is odd. . I'm using a music album. Hmm, I guess you just have to get lucky.

I would assume you wouldn't use a blank cd/dvd or a burned one because they dont have the microscopic pits which may make your cool reflection. Am I right? Or can you use any cd?

I've seen simple lines and curves using a pointer, maybe more power is reqiured

Most likely you need a commercial cd that has the reflective aluminum foil layer and not the burnable ones that have dye instead.

on the top of some of my cds if you shine on the label it will make 4 lines off of it.