This illumination follows {HEAD ~ a path} through the objective toward the sample, and again, after reflection, through {TAIL ~ the objective} toward the detector 
through
This illumination follows { HEAD ~ a path } through the objective toward the sample , and again , after reflection , through { TAIL ~ the objective } toward the detector
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH