Laser radar with remote local oscillator

US10180496B2 · kind B2 · utility

Assignees

• NIKON CORPORATION · JP
• NIKON METROLOGY NV · BE

Inventors

• Daniel Gene Smith · Tucson, US
• Eric Peter Goodwin · Oro Valley, US
• Anthony R. Slotwinski · Salem, US
• Mina Rezk · Haymarket, US
• Alexander Cooper · Belmont, US
• Thomas M. Hedges · Great Falls, US

Key dates

• Filing date: Mar 15, 2013
• Grant date: Jan 15, 2019
• Expiry date: Nov 13, 2035

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S17/66
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Laser radar systems include a pentaprism configured to scan a measurement beam with respect to a target surface. A focusing optical assembly includes a corner cube that is used to adjust measurement beam focus. Target distance is estimated based on heterodyne frequencies between a return beam and a local oscillator beam. The local oscillator beam is configured to propagate to and from the focusing optical assembly before mixing with the return beam. In some examples, heterodyne frequencies are calibrated with respect to target distance using a Fabry-Perot interferometer having mirrors fixed to a lithium aluminosilicate glass-ceramic tube.