!%Advanced Photonix Inc.%! of Ann Arbor, Mich., has received a follow-on, 21-month, $1.5 million contract from the US Air Force to provide terahertz process control instrumentation to support F-35 joint strike fighter production. The contract is a commercialization pilot program award to ensure the quality of specialty stealth coatings applied by Northrop Grumman to a subsystem on the F-35. Once completed, the system will consist of the T-Ray 4000 control unit, which is connected to a miniature terahertz transceiver via a flexible umbilical up to 100 m in length mounted onto an existing robot arm within a paint booth.