Defense electronics company Elbit Systems Ltd. announced that its wholly owned subsidiary, Elop Electro-Optics Industries Ltd. (El-Op), has received orders for more than $53 million from international customers for thermal imaging day/night observation systems for various military and security applications. The equipment is due to be supplied over a period of 18 months.   . . .   Lumera Corp., a subsidiary of Microvision Inc., announced it has been awarded a second contract extension for an additional $950,000 from a US government agency to continue development of high-performance electro-optic polymer materials and devices for wideband optical modulators. The award brings the total funding for development work from this agency to about $3.5 million. The third stage in this contract is expected to be completed within a year, Lumera said.