An electrode-inlead assembly comprises a small tungsten pin which is joined on axis to a fine molybdenum wire adapted to sealing through fused silica. The join is effected by a laser butt weld which permits a symmetric compact seal thereby making possible very small discharge envelopes having minimum end losses. The seal may be effected either by a foliated portion in the wire which is wetted by fused silica, or by a glass bead formed around the wire which wets both wire and fused silica.