Tech Briefs Magazine - May 2022 - 44

Optics
Nanocomposite Material Protects Against Intense Light
Optical limiting safeguards drones, surveillance cameras, and other equipment against laser
attacks, which can disable or destroy the equipment.
University of Houston, TX
O
ptical limiting - a manner of
telecom switching without the
use of electronics - is an all-optical
method that could improve the
speed and capacity of Internet communications.
A material created using
tellurium nanorods - produced
by naturally occurring bacteria - is
an effective nonlinear optical material
capable of protecting electronic
devices against high-intensity bursts
of light, including those emitted by
inexpensive household lasers targeted
at aircraft, drones, or other
critical systems.
While most optical materials are
chemically
synthesized,
the
new
technology uses a biologically based
nanomaterial that is less expensive and
less toxic. Using bacteria to create the
nanocrystals suggests an environmentally
friendly route of synthesis.
Light at very high intensity, such as
that emitted by a laser, can have unpredevice
to be developed that could
prevent damage by that light.
The nanocomposite, made up
of biologically generated elemental
tellurium nanocrystals and a
polymer, was used to build an electro-optic
switch - an electrical
device used to modulate beams of
light - that is immune to damage
from a laser.
Optical limiting provides a new way to safeguard drones,
surveillance cameras, and other equipment against laser
attacks, which can disable or destroy the equipment.
(Photo: Pexels)
dictable polarizing effects on certain
materials. Suitable nonlinear materials
that can withstand the effects have not
previously been found. The goal is to
find a material that can effectively reduce
the light intensity, allowing for a
The biologically generated tellurium
nanorods are especially
suitable for photonic device applications
in the mid-infrared range
such as biomedical, environmental,
and security-related sensing as well
as laser processing and fiber optic
and free-space communications.
Work will continue to expand the
material's potential for use in all-optical
telecom switches, which is critical
in expanding broadband capacity.
For more information, contact Jeannie
Kever at jekever@uh.edu; 713-743-0778.
New Family of Glass for Lens Applications
The new glass can be manufactured on a mass scale.
Pennsylvania State University, University Park, PA
A
new composition of germanosilicate
glass created by adding zinc
oxide has properties good for lens applications.
The new family of zinc germanosilicate
glass has a high refractive
index comparable to that of pure
germania glass. Samples showed high
transparency, good ultraviolet-shielding
properties, and good glass forming
ability, making them suitable
for lens applications. Germanosilicate
glass is essential
in the manufacture of optical
amplifiers, waveguides, and
solid-state lasers.
The refractive index of glass
determines its use. The benefit
of a high-refractive index is its
capacity for designing low-thickness
lenses. In glass synthesis,
however, achieving a high refractive
index typically has a few
roadblocks. Lead oxide can ac44
complish
this but requires the use of toxic
raw materials. Non-lead constituents
that encourage a high refractive index
can make the glass much more difficult
to form or prone to crystallization and
therefore more opaque. By finding the
optimum balance of zinc oxide with the
other components of the glass composition,
these issues were avoided.
Zinc oxide showed UV shielding properties
in the study samples; this was expected
given that inorganic sunscreen is
based on zinc oxide. With UV shielding,
a zinc-oxide-containing glass could be
used for everyday applications such as
car windows or eyeglasses.
A researcher trims glass from a crucible. (Photo: Penn State)
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The glass samples also showed favorable
forming properties. As a " long
glass, " the new compositions can
be formed over a broader temperature
range, making them
much simpler to manipulate
during formation. This property,
the resistance to crystallization,
and the lower cost of zinc oxide
compared to germania all make
the new glass composition a
practical choice for manufacturing
on a mass scale.
For more information, contact
Patricia L. Craig at plc103@psu.
edu; 814-863-4663.
Tech Briefs, May 2022
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