Since {TAIL ~ the laser light intensity} becomes lower in {HEAD ~ continuous oscillation} than in pulse oscillation, modified regions can be formed in the intermediate portion but not in one end portion and the other end portion 
Since { TAIL ~ the laser light intensity } becomes lower in { HEAD ~ continuous oscillation } than in pulse oscillation , modified regions can be formed in the intermediate portion but not in one end portion and the other end portion
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH