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

Patent · Wed Jan 01 00:00:00 EST 1997

OSTI ID:871238

Strauss, Charlie E ^[1]

---

1. Santa Fe, NM

Apparatus and method 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.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• DOE Contract Number: W-7405-ENG-36
• Assignee: Regents of University of California (Los Alamos, NM)
• Patent Number(s): US 5689335
• OSTI ID: 871238
• Country of Publication: United States
• Language: English

Related Subjects

apparatus
method
heterodyne-generated
two-dimensional
detector
array
single
element
synthetic-array
heterodyne
detection
permits
single-element
optical
behave
divided
separate
elements
fifteen-element
synthetic
successfully
experimentally
realized
permitting
continuously
parallel
electrical
connection
laser
hgcdte
photodiode
employed
local
oscillator
frequency
incident
spatially
resolvable
regions
surface
mapped
beat
frequencies
determine
photons
prevents
destructive
interference
occurs
multiple
speckles
imaged
similar
spatial
diversity
coherent
lidar
larger
field
view
acoustooptic
modulator
generates
achieve
adequate
separation
megahertz
apart
optical detector
single element
detector apparatus
detector array
electrical connection
detector element
local oscillator
single electrical
detector elements
two-dimensional detector
heterodyne detection
single-element optical
array element
/356/359/