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