“…Quarter-wave distributed Bragg reflectors (DBRs) of high reflectivity are extensively used in optical devices such as vertical cavity surface emitting lasers (VCSELs) [1,2], resonant-cavity lightemitting diodes (RCLEDs) [3,4] and also recently in optically pumped vertical extended cavity surface emitting lasers (VECSELs) [5,6], semiconductor saturable absorber mirrors (SESAMs) [7,8], and light beam intensity modulators (LBIMs) [9,10]. All those applications impose the highest requirements on the reflectivity of Bragg mirrors, which often have to be higher than 98%, the limit of silver-coated mirrors.…”