In one embodiment a dispersive element is used to reflect {HEAD ~ the input beam} at different angles depending on {TAIL ~ the incident wavelength} 
In one embodiment a dispersive element is used to reflect { HEAD ~ the input beam } at different angles depending on { TAIL ~ the incident wavelength }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL