Tech Briefs Magazine - February 2022 - 28

Optics
Photonic Integrated Chip for Improved Light Control
This combination of technologies could enable developments for many optical applications.
Pennsylvania State University, University Park, PA
new technology that can allow for
better light control without requiring
large, difficult-to-integrate materials
and structures has been developed. The
photonic integrated chip could allow
for many advances in the optical field
and industry, ranging from improvements
in virtual-reality glasses to optical
remote sensing.
Traditionally, scientists have had two
options when it comes to controlling
light for use in various optical devices.
The first is a photonic integrated circuit
(PIC) that can be incorporated onto
small chips but has limited ability to control
free-space light - light propagating
in air, outer space, or a vacuum, as
A
opposed to being guided in fibers or
other waveguides. The second is a newly
emergent metasurface - an artificially
engineered thin layer that allows for
light manipulation at subwavelength
scale but cannot be integrated on a chip.
Researchers solved this problem by
incorporating the best qualities of the
two previous options into a new, hybrid
photonic architecture that has metasurfaces
integrated onto a PIC chip while
maintaining high light controllability.
Incorporation of the PICs and metasurfaces
makes it possible to drive the
metasurfaces using guided waves inside
the PICs. It enables routing of light
among different metasurfaces, performing
multiple complex functions on
a single chip.
This new development could have
applications in optical communications,
optical remote sensing - LiDAR - freespace
optical interconnects for data centers,
and virtual reality and augmented
reality displays. The hybrid system has
the advantages of both the metasurfaces
and the PICs. In addition, the design is
highly flexible and modular. A library of
the building blocks can be established
for reusing and creating consistent functional
components across various de -
vices or systems.
For more information, contact Megan
Lakatos at mkl5024@psu.edu; 814-865-5544.
Sub-Pixel Spatial Resolution Interferometry
Applications include aircraft-mounted and space-based interferometers, electronics
fabrication, and military optics.
Marshall Space Flight Center, Huntsville, AL
nnovators at NASA Marshall, in conjunction
with the Center for Applied
Optics at the University of Alabama in
Huntsville, developed a system that
increases the spatial resolution of interferometric
measurements of optical surfaces
beyond the fundamental Nyquist
Limit of the interferometer's imaging
system/detector. The Sub-Pixel Spatial
Resolution Interferometry (SSRI) system
enables optical fabricators to accurately
qualify surface features of spatial
frequencies that could not be accurately
resolved using standard interferometers.
Current trends in optical design are
producing new types of specifications,
requiring distinct spatial frequency
bands and calling for larger aperture
optics; however, the ability to characterize
these features over the full aperture
necessitates improvements. The SSRI
system meets this need by increasing the
spatial resolution of full aperture interferometric
measurements using a technique
that incorporates interlaced
stitching of low-resolution measureI
28
Cov
(a)
(b)
(c)
(a)
Low-resolution interferometer measurement; (b) Constructed high-resolution data using SSRI;
(c) Measurement at twice the resolution of (a). The SSRI constructed data (a) is identical to that
obtained when measuring the sample at twice the resolution (c). (Photo: NASA)
ments taken at sub-pixel lateral shifts to
enhance spatial resolution.
The SSRI system increases the spatial
resolution of the interferometric measurements
by performing multiple measurements
of an optical surface with subwww.techbriefs.com
ToC
pixel
shifts between a charged coupled
device (CCD) detector and the optic
under test between measurements. The
measurements are then combined to
create a single measurement with higher
spatial resolution.
Tech Briefs, February 2022

http://www.techbriefs.com http://info.hotims.com/82318-800

Tech Briefs Magazine - February 2022

Table of Contents for the Digital Edition of Tech Briefs Magazine - February 2022