Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector

Patent · Tue Nov 18 04:00:00 EST 1997

OSTI ID:563711

Strauss, C E

Apparatus and method are disclosed for heterodyne-generated, two-dimensional detector array using a single detector. Synthetic-array heterodyne detection, permits a single-element optical detector to behave as though it were divided into an array of separate heterodyne detector elements. A fifteen-element synthetic array has successfully been experimentally realized on a single-element detector, permitting all of the array elements to be read out continuously and in parallel from one electrical connection. A CO{sub 2} laser and a single-element HgCdTe photodiode are employed. A different heterodyne local oscillator frequency is incident upon the spatially resolvable regions of the detector surface. Thus, different regions are mapped to different heterodyne beat frequencies. One can determine where the photons were incident on the detector surface even though a single electrical connection to the detector is used. This also prevents the destructive interference that occurs when multiple speckles are imaged (similar to spatial diversity), In coherent LIDAR this permits a larger field of view. An acoustooptic modulator generates the local oscillator frequencies and can achieve adequate spatial separation of optical frequencies of the order of a megahertz apart. 4 figs.

• Research Organization: University of California
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• Assignee: Univ. of California, Los Alamos, NM (United States)
• Patent Number(s): US 5,689,335/A/
• Application Number: PAN: 8-540,434
• OSTI ID: 563711
• Country of Publication: United States
• Language: English

Related Subjects

44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
CARBON DIOXIDE LASERS
DESIGN
MEASURING INSTRUMENTS
OPTICAL RADAR
OPTICAL SYSTEMS
PHOTODIODES
READOUT SYSTEMS