The present galvanometer mirrors may be manufactured by four different methods: (1) polishing of bare beryllium, (2) electroless plating of Ni, (3) polishing or single diamond-point of electroplated Ni, and (4) thin-film epoxy replication. The IR reflectivity of beryllium in the 3-14 microns range is sufficiently high to obviate additional mirror coatings, while electroless Ni and epoxy-replicated mirrors require a subsequent coating to achieve the requisite reflectivities. Nevertheless, there are galvanometer configurations that do not lend themselves to polishing. Replication is the lowest-cost mirror-fabrication method.
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