Although not mentioned explicitly throughout the text, the Bragg reflectors can of {HEAD ~ any type} of distributed reflector such as, for example, a photonic bandgap crystal where the Bragg reflector is constructed by series of {TAIL ~ holes} in a dielectric material 
Although not mentioned explicitly throughout the text , the Bragg reflectors can of { HEAD ~ any type } of distributed reflector such as , for example , a photonic bandgap crystal where the Bragg reflector is constructed by series of { TAIL ~ holes } in a dielectric material
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH