Can I make pulsing light using AC as source, a diode and a LED?
The diode in series with an AC source over to a load will indeed pulse the current through the load. It may very well be hard for you to see it pulsing however. 

For a light bulb load with a heated filament the heating time constant will tend to integrate the current pulses into an average temperature that will appear to be a fairly constant brightness to the human eye.

The light from an LED load will pulse with the applied current pulses. However at the 50 or 60 Hz of the normal AC line frequency you will be unlikely to see the flashing with your eye. The threshold for most human eyes to be able to detect a flashing light is around 22 to 25 Hz. The eye and brain perform an averaging function whose time constant is a low pass filter to 50 or 60Hz signalling.