etching {HEAD ~ a negative} of a desired multiple discrete level diffraction pattern onto a molding surface of a quartz master element using {TAIL ~ photolithography} 
etching { HEAD ~ a negative } of a desired multiple discrete level diffraction pattern onto a molding surface of a quartz master element using { TAIL ~ photolithography }
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL