World’s most complex 2D laser beam created
Researchers, including one of Indian origin, have
demonstrated the most complex 2-D optical phased array ever that can
generate high-resolution beam patterns.
The new 2-D
optical phased array technology will enable advanced Light Detection And
Ranging (LADAR) and other defence applications.
LADAR provides a more detailed level of information that can be used for applications such as rapid 3-D mapping.
The
array, which has dimensions of only 576 micro metre x 576 micro metre,
roughly the size of the head of a pin, is composed of 4,096 (64 x 64)
nanoantennas integrated onto a silicon chip.
Key to
this breakthrough was developing a design that is scalable to a large
number of nanoantennas, developing new micro-fabrication techniques, and
integrating the electronic and photonic components onto a single chip.
“Integrating
all the components of an optical phased array into a miniature 2-D chip
configuration may lead to new capabilities for sensing and imaging,”
said Sanjay Raman, program manager for DARPA’s Diverse Accessible
Heterogeneous Integration (DAHI) program.
“By bringing such functionality to a chip-scale form
factor, this array can generate high-resolution beam patterns -- a
capability that researchers have long tried to create with optical
phased arrays.
“This chip is truly an enabling
technology for a host of systems and may one day revolutionise LADAR in
much the same way that ESAs revolutionised RADAR. Beyond LADAR, this
chip may have applications for biomedical imaging, 3D holographic
displays and ultra-high-data-rate communications,” said Raman.
Radio
frequency (RF) waves travel through the atmosphere, reflect off of a
target, and return to the RADAR system to be processed.
The
amount of time it takes to return correlates to the object’s distance.
In recent decades, this technology has been revolutionised by
electronically scanned arrays (ESAs), which transmit the RF waves in a
particular direction without mechanical movement.
Each
emitter varies its phase and amplitude to form a RADAR beam in a
particular direction through constructive and destructive interference
with other emitters.
Similar to RADAR, laser
detection and ranging, or LADAR, scans a field of view to determine
distance and other information, but it uses optical beams instead of RF
waves.
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