{TAIL ~ The screen} is scanned by a laser spot having {HEAD ~ a diameter} which is less than 100 micrometer 
{ TAIL ~ The screen } is scanned by a laser spot having { HEAD ~ a diameter } which is less than 100 micrometer
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH