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