Non-tradition-employed lenses

Non-tradition-employed (NTE) lenses are presented. The characters are proved by the experiment. Multilayer reflection coatings on designated zones on the surfaces of the lens are different in reflectivity(R) because of different NTE aims. Incident light beams paraxially bounce back and forth between two surfaces of the lens, then leave from a zone or multiple zones of the lens. The application schemes involve solid-state multiple-pass cell, combination of light beams or laser beams, and phase-locking of a laser array.