Best distance sensor

Other Hardware Sensors
1

Hello all,

I'm looking for the best sensor for distance to use with Arduino.
The problem is that i need to check for small delta-distance. I have a rotating table that isn't perfectly planar and it have a +- 1,5 mm distorsion.
How can i measure delta-distances of 0,1 mm?

I've tried with "Ultrasonic Module HC-SR04" but without great success.

Any help?

Thanks,

2

I've just tried laser emitter+photoresistor. Seems to be a good option.
Any suggestion?

3

0.1 mm over km?

4

0.1 mm in distances between 10-12 mm and slow movement (about 1 mm every 30 seconds)

5

Short range - Sharp may be good option.