I am in the middle of final setting. And then I discovered a serious problem. 

I DON'T HAVE ANY SAMPLE! 

It may sound funny but I can't use any surface. I mean I can use any surface but it useless. It will not tell me if there is a lot of noise or maybe it doesn't work at all and there is some garbage/noise that looks flat...

I've recalled that someone used CD-ROM pits to test his device. So I found some old CD-ROM. 

Under the microscope it looks like 

I've focused on the numbers each CD ROM disc has before actual data. 

Are those the pits and grooves? Let's take a close look.

It does look like the grooves. Let's look at the data

It's not clear her from this picture but there is no pits but  straight parallel lines.

This is a writable CD-ROM. Let's take a look at read only CD-ROM.

Here we can see the pitches and the data itself looks like:

Here we don't see the groves only the pitches. Those two CD-ROMs can be used to varify if our AFM is working