1. science
2. physics
3. optics

2005
How to Get Published in Photonics Tech Briefs
Photonics Tech Briefs (PTB), a market focus supplement selectively bound into NASA Tech Briefs,
covers innovative technologies developed by NASA’s R&D centers and contractors — focusing on
commercial applications in optics, fiber optics, lasers, electro-optics, imaging, and test & measurement.
These “tech briefs” are accompanied in the magazine by a variety of additional editorial content,
including vendor contributed tech briefs, new product information, and feature articles. Opportunities
to submit materials for the editor’s consideration are outlined below.
Tech Briefs
Feature Articles
The core of PTB editorial consists of concise articles
describing NASA innovations that have commercial or industrial
utility. These tech briefs are written by the engineers or scientists
who created the technology, and are edited so that engineers
across different disciplines can
grasp the idea and its applications
Inverse Tomo-Lithography for Making Microscopic 3D Parts
quickly.
Companies working on R&D
projects with any of the ten NASA
field centers may submit a tech
brief through the appropriate
center’s Technology
Commercialization Office. (A list of
these offices and
contact points is
Improved Apparatus for Measuring Distance Between Axles
included in each issue
of NASA Tech Briefs.)
Candidate briefs are
evaluated and graded
by NASA experts to
ensure that the subject
technology is novel and
has practical
applications. Only onethird of the briefs
submitted will make the
grade and appear in
the publication.
Photonics Tech Briefs
Inverse tomography would be used to generate complex three-dimensional patterns.
NASA’s Jet Propulsion Laboratory, Pasadena, California
According to a proposal, basic x-ray
mask pattern along the direction of inciIn the proposed technique, one would
lithography would be extended to incordence of the radiation.
essentially reverse this decoding process;
porate a technique, called “inverse toIn a recently developed variant of
that is, one would encode or construct a
mography,” that would enable the fabriLIGA, a rotating PMMA rod is exposed to
three-dimensional pattern by illuminatcation of microscopic three-dimensional
x-rays through a stationary mask; this teching the region of interest in a changing
(3D) objects. The proposed inverse
nique can be used to make axisymmetric
two-dimensional pattern: That is why the
tomo-lithographic process would make
structures; e.g., objects shaped like wine
proposed x-ray exposure technique is
it possible to produce complex shaped,
glasses or baseball bats. The proposed
called “inverse tomography.”
submillimeter-sized parts that would be
technique would also involve stenciling an
The figure depicts an example of the
difficult or impossible to make in any
x-ray image into a rotating PMMA rod,
use of this technique to generate a simother way. Examples of such shapes or
but would differ from prior techniques in
ple helix. The two-dimensional projecparts include tapered helices, parabothat the mask would be moved in syntion (shadow) of a helix is a sinusoid. To
loids with axes of different lengths,
chronism with the rod to generate a
form the helical pattern in a PMMA rod,
and even Archimedean
screws that could serve as
rotors in microturbines.
The proposed inverse
EXPOSURE TO X-RAYS
tomo-lithographic process
would be based partly on
Motion of
X-Rays
a prior microfabrication
Mask
process known by the
German acronym “LIGA”
(“lithographie, galvanoformung, abformung,” which
means “lithography, electroforming, molding”). In
LIGA, one generates a precise, high-aspect ratio patRotating
tern by exposing a thick, xPMMA Rod
ray-sensitive resist material
DEVELOPMENT
to an x-ray beam through a
mask that contains the pattern. One can electrodeMask Containing
Sinusoidal
posit metal into the develAbsorber Pattern
oped resist pattern to form
a precise metal part, then
dissolve the resist to free
Photonics Tech Briefs
HELIX REMAINING
the metal. Aspect ratios of
AFTER DEVELOPMENT
100:1 and patterns into resist thicknesses of several
millimeters are possible.
Typically, high-molecularAccuracy is double that of the previous version.
weight poly(methyl methacrylate) (PMMA) is used as the
JohntoF.collimated
Kennedyx-rays
Spacethrough
Center,
Florida
A Rotating PMMA Rod would be exposed
a mask
bearing a sinusoidal absorber pattern
resist material. PMMA is an while the mask moved along the rod in synchronism with the rotation. Upon development of the PMMA (used here
would
remain. version of an optoelecexcellent resist material in as an x-ray photoresist material), a helixAn
improved
The range finder was aligned precisely
most respects, its major
tronic apparatus for measuring diswith respect to the laser-diode modules
of the
order
of tens ofone
feet with
an project
and the
diverging
lenses so that the line
shortcoming being insensitivity. Conventhree-dimensionaltances
pattern.
The
synchrowould
x-rays
perpendicuerror
no and
larger
a smalllarly
fraction
of the of
sight
of thea range
finder was perpentional x-ray sources are not practical for
nized motions of the
mask
rodthan
would
toward
rod
through
mask with
an inch (aand
fewrotation
millimeters)
has been pattern
dicularwhile
to the
planethe
defined by the
LIGA work, and it is necessary to use a
be generated by translation
a sinusoidal
rotating
Likemotors
the previous
the prebeams
laser-diode
modules.
synchrotron as the source. Because synstages actuated bybuilt.
stepping
under version,
rod and
translating
thefrom
maskthe
along
the
sent improved version of the
This
of sight of
was
chrotron radiation is highly collimated
control by a computer.
rodapparatus
at a speed of
oneline
wavelength
thethus nominally
designed
to measure
the distance
≈66
ft rotation
horizontal.
The apparatus was mounted
and its wavelength of synchrotron radiaDescribing theis x-ray
exposure
techsinusoid
per
period.
(≈20
m) between
the axes of rotation
of wason
a tripod
(between
the rear tires, in
tion is typically <5 Å, there is very little
nique in different
words,
a changing
This work
done
by Victor
White and
the frontwould
and rear
spaceWiberg
shut- of the
case for
of aNASA’s
space shuttle)
with the
diffraction and the pattern of a high-contwo-dimensional pattern
betires
pro-of theDean
Caltech
Jet
tle orbiter as it one.
rests In
in a ground-based
range finder
at approximately
the
trast mask is projected deep into a resist
jected into a three-dimensional
Propulsion Laboratory.
For further
inforLike the previous
ver- theheight
of Support
the distant
object of interest
with nearly perfect vertical sidewalls. Of
tomography, oneprocessing
decodes facility.
a three-dimation, access
Technical
Package
sion, the present version could also be
front tire hub in the case of the
course, the only three-dimensional shape
mensional pattern
from the changing
(TSP) free on-line(the
at www.nasatech.com/tsp
adapted for similar purposes in other
space shuttle). Exact matching of
that can be formed in this way is the
two-dimensional pattern obtained by ilunder the Manufacturing category.
settings: Examples include measuring
heights was not necessary in this applicalocus of points generated by moving the
luminating it from a changing direction.
NPO-20593
perpendicular distance from a wall in a
tion because the geometry was such that
building, placement of architectural
even at a height difference as large as a
4a
www.ptbmagazine.com
Tech Briefs, June 2003
foundations, and general alignment andPhotonics
few inches,
the difference between the
measurement operations.
horizontal distance and the measured
The previous version was described in
distance was less than the allowable
“Apparatus and Technique for Measurerror of 1/8 in (≈3.2 mm). A target was
ing Distance Between Axles” (KSCmounted on the distant object of inter11980), NASA Tech Briefs, Vol. 25, No. 3
est (the front tire hub). The position
(March 2000), page 76. To recapitulate:
and orientation of the apparatus were
The major components of the apparaadjusted until the bright lines projected
tus were (1) a laser range finder and (2)
by the fan beams struck the near objects
laser line projectors that included two
of interest (the hubs of both rear tires in
battery-powered laser-diode modules
the space-shuttle application) and the
with collimating optics. Each laser-diode
beam from the range finder struck the
module generated a continuous-wave
center of the target. Then the distance was
beam with a power of 3 mW at a wavemeasured by use of the range finder, which
length of 670 nm. The modules were
produced a digital readout. The measureaimed to point the beams downward,
ment range was from <1 ft (<0.3 m) to
and the beams were made to pass
about 300 ft (≈91 m).
through cylindrical diverging lenses to
The differences between the previous
spread the beams into fans oriented in a
and present versions are the following:
nominally vertical plane. The modules
• In the previous version, an optical aswere aligned to project coincident vertisembly containing the laser fan-beam
cal lines as viewed from the side and
generators and the laser range finder
collinear horizontal lines as viewed
was aligned by sliding it on top of a
from the top.
platform attached to a tripod. Because
Base Plate With Rails
Optical Assembly
this alignment process proved awkward
in practice, rails were added so that the
optical assembly could be aligned more
precisely and then locked in position.
As shown in the left part of the figure,
there are two pairs of parallel rails for
left/right motion of the assembly and a
single rail for forward/backward motion of the assembly.
• The original range finder was replaced
with a newer and more accurate one, reducing the measurement error to within
a tolerance of l/16 in. (≈1.6 mm).
• Rechargeable batteries that were used
in the original version were found to
last only a couple of years. They were
replaced by batteries of common nonrechargeable AA-size cells.
• The original tripod was replaced with a
more rugged one.
• Hinged plates with simple pull pins were
installed to afford access, for replacing
batteries without need to use tools.
• In the previous version, it was necessary to cut cylindrical lenses and glue
them to the laser diodes. During the
last few intervening years, much better
laser devices arrived on the market.
Therefore, the original laser diodes were
replaced by laser-diode assemblies that
include built-in adjustable focus devices so that the projected lines can be
made narrow, increasing the accuracy
of apparatus.
This work was done by Douglas E. Willard
of Kennedy Space Center and Ivan I.
Townsend III of Dynacs, Inc. For further information, contact the Kennedy Technology
Programs and Commercialization Office at
(321) 867-8130.
KSC-12391
Optical Assembly Mounted on Rails
Parts of the Improved Distance-Measuring Apparatus are shown here, variously, by themselves and assembled with other parts. [A ruler in each photo is
approximately 6 in. (15 cm) long.]
6a
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Photonics Tech Briefs, September 2003
Vendor-Contributed Tech Briefs
Companies that have
developed or perfected a
Distributing Digital Signals to Multiple Destinations
particular technology or
process may submit vendorcontributed tech briefs. These
briefs are written in similar
fashion to the NASA tech briefs
described above. Tech briefs
must include information on
how the technology was
developed, its novelty or
120-GHz HEMT Oscillator With Surface-Wave-Assisted
Antenna
uniqueness, specifications
related to how the technology
operates, and the commercial
applications and uses for the
technology.
Briefs may now be submitted via an online form at
www.techbriefs.com/briefsubmit. Contact the editor
for guidelines on how to develop a tech brief.
Photonics Tech Briefs
Fanout Buffer Modules Address Lab Requirements
Pulse Research Lab (PRL), Torrance, California
Digital signal fanout is a very comdaily laboratory use involves more
GHz. These devices offer solutions to
mon requirement in testing, experithan just breadboarding. It requires
the engineer working within the relamentation, and systems integration.
a PC board with controlled impedtively small confines of a circuit board.
Unlike radio frequency signals, highance I/O lines, an enclosure, I/O
In order to accomplish the above
speed digital signals cannot be simply
connectors, power supplies, and
tasks at the instrumentation and intersplit or “teed” off to multiple destinacomponents for biasing of the I/O
connect level, a series of self-contained,
tions. Even with a matched-impedance
circuits, etc.
fanout buffer modules (for TTL and
splitter, the resulting amplitude loss
When considering common tasks in
ECL) have been developed to give engiwould render most clock and logic sigthe digital electronics domain, such as
neers the ability to fanout TTL signals
nals incompatible with the receiver.
clock distribution to multiple reup to 100 MHz and NECL/PECL/
To preserve logic level compatibility,
ceivers, data fanout to multiple reLVPECL signals up to 3 GHz. The outdigital signals must be actively
ceivers, and synchronous triggering of
put driver circuitry is designed to drive
buffered when they are fanned out.
multiple receivers, semiconductor
50Ω loads while preserving timing fiSeveral factors must be controlled
manufacturers offer numerous devices
delity and logic-level amplitudes. With
when building a fanout buffer for lab
for signal fanout at the PCB level. For
proper load termination, TTL models
use, and each becomes more difficult
example, one device provides 1:6 TTL
can drive up to 100 feet of cable, and
at higher data rates and with longer
fanout up to 100 MHz, and another
differential ECL models can drive up to
cable lengths:
provides 1:2 fanout for ECL up to 2.5
200 feet of cable. TTL and PECL mod• If the transmission distance is a
els also have back-termination for
“long line,” (i.e. if the propagadriving un-terminated loads.
tion delay t prop to the receiver is
Practical considerations, such as
> 20-25% of the rise-time tr of
efficiency and cost-effectiveness in
the signal) a controlled-impedthe lab, should be factored into
ance environment is mandathe build-vs.-buy equation. Altory. When driving a long line,
though conceptually simple, a
either the driver must have a
project like this can consume
back termination, or else the
hours or days of troubleshooting
line must be terminated at the
time. Furthermore, projects like
receiving end.
these are not highly repeatable,
• When driving very long cables
unless a PC board is laid out,
(in excess of 10' - 20'), series rewhich again involves additional
sistance and the “skin effect” of
time and cost.
the cable will degrade the signal
This work was done by David Kan
amplitude, requiring the output
and Steven Kan for Pulse Research
driver to have significant headLab (PRL). For more information on
room to trigger the receiver reliusing PRL’s Fanout Buffer Modules,
ably.
contact Pulse Research Lab, 1234 Fran• Once a suitable circuit has been
cisco Street, Torrance, CA 90502; Tel:
designed, carefully integrating PRL Fanout Buffer Modules distribute high-speed, digital sig- (310) 515-5330; Fax: (310) 515-0068;
all the necessary components for nal from single source to multiple destinations in the lab.
www.pulseresearchlab.com/fanout
This is a compact, lightweight alternative to vacuum-tube oscillators.
NASA’s Jet Propulsion Laboratory, Pasadena, California
Two monolithic microwave integrated
circuits (MMICs) have been designed
and built to function together as a source
of electromagnetic radiation at a frequency of 120 GHz. One of the MMICs is
an oscillator and is the highest-power
120-GHz oscillator reported thus far in
the literature. The other MMIC is an
end-fire antenna that radiates the oscilla64
tor signal. Although these MMICs were
constructed as separate units and electrically connected with wire bonds, future
oscillator/antenna combinations could
readily be fabricated as monolithic integrated units. Such units could be used as
relatively high-power solid-state microwave sources in diverse applications
that include automotive radar, imaging,
www.ptbmagazine.com
scientific instrumentation, communications, and radio astronomy. As such,
these units would be attractive alternatives to vacuum-tube oscillators, which
are still used to obtain acceptably high
power in the frequency range of interest.
The oscillator (see figure) includes a
high-electron-mobility transistor (HEMT),
with gate-periphery dimensions of 4 by
Photonics Tech Briefs, February 2003
Contributed and staff-written
Advanced Near-Infrared Cameras:
feature articles focus on a different
Successful Application
topic each month. Articles provide
in the 900-to-1700 nm Band
either a comprehensive overview
M
on a topic, or an in-depth
discussion on a
PTB Exclusive
particular technology.
What’s Next for Optical
Refer to the
Design Software?
Technology Focus &
T
Special Features
columns of PTB’s
editorial calendar for
the topics covered in
each issue.
Companies wishing
to contribute or
participate in a feature
article should contact
the editor for details.
wo dominant forces are driving
today’s market for optical design
software: a shift in the academic
and professional background of its user
base and the emergence of the nonimaging segment. This is, of course,
aided by a positive upswing in the economy. “It’s not showing in jobs, but we are
seeing people who were afraid to spend
money the last few years suddenly willing
to invest in tools, like software, to help
them develop their products,” said Dr.
Edward Freniere, president of Lambda
Research Corp. in Littleton, MA.
Despite the significant variance in the
cost of optical design software packages,
general consensus is that perceived
value is more of an issue than pricing
alone. Ease-of-use, or usability, is also an
influencing factor, partially because the
user base consists largely of people inexperienced in optical design.
End Users
The industry experts we talked to
agree that developers of optical design
programs cannot depend on their users
having formal training or a substantial
amount of experience in the optics discipline -— a notable difference between
this market and electrical or mechanical
engineering. “In optics it is different because there are very few schools of optics
compared to the number of people who
are needed to do optical engineering,”
explained Bob Hilbert, president and
CEO of Optical Research Associates,
Pasadena, CA. “We have gotten used to
the idea that a lot of the best optical engineers don’t have an optical degree.
They are engineers or physicists who
have learned optics in their own time, in
special courses, and through their own
experience.” Hilbert also points out that
this trend is even more pronounced for
the engineers doing non-imaging work
rather than imaging projects.
Many experts stressed that today’s offerings typically have the capability to
solve all but the most advanced user
problems; inexperienced users, how2a
any imaging applications in
tors combine to boost the cost of this
the very low light levels encountered in
the near-infrared (NIR) retype of camera. In addition, mechanical
spectroscopy. Other applications ingion of the spectrum require
cryocooler life is a limiting factor. The
clude semiconductor wafer inspection,
sensors that see beyond
coolers cost about $10,000, making relaser-beam characterization, and water
the traditional charge-coupled device
placement costly in applications where
and chemical detection.
(CCD) sensor’s spectral range. A stanthe camera runs continuously.
Alternatives & Limitations
dard uncoated CCD detector cuts off at
In contrast, because the bandgap enSilicon is transparent at wavelengths
a wavelength of around 1100 nm, where
ergy of InGaAs is much higher than for
longer than 1100 nm, which makes silithe silicon becomes transparent. Special
InSb, InGaAs FPAs can operate at temcon-based cameras ineffective at wavewaveshifting coatings can push this cutperatures around ambient (25 °C), with
lengths longer than that unless they are
off wavelength out to 1600 nm and benoise performance comparable to InSb
coated with a wave-shifting material. But
yond, but the sensitivity of the coated
sensors at liquid nitrogen temperatures.
the downside of the coating is that it
sensor decreases dramatically. A better
The thermoelectric coolers used with
drastically lowers quantum efficiency of
detector material is required for many
these FPAs cost about $20, making the
the material to 1-2% in the 1100-1700 nm
applications that demand high sensitivoverall camera much less expensive.
waveband. That limits its use primarily to
ity and a spectral response out beyond
FPA Fabrication
laser beam profiling — an application in
1600 nm. Indium gallium arsenide
InGaAs FPAs are fabricated by growwhich intensities are high.
(InGaAs) is that material.
ing photodiodes on 3-inch-diameter
High sensitivity is important because
InGaAs detectors offer quantum effiwafers. The wafers are made by metalthe scenes typically viewed in NIR
ciencies of ~85% in the 900-1680 nm
oxide chemical vapor deposition
imaging cover a wide dynamic range,
waveband, which is higher than the
(MOCVD) of InGaAs onto indium
and the intensity of light signals can be
competing technologies of lead-oxysulphosphide (InP) wafers. The FPA devery low. That is especially true in NIR
fide vidicons and coated CCD cameras.
tectors are approximately 30 microns
imaging spectroscopy, where only a
Commercially available NIR cameras
square, and are made by diffusing a
small portion of the InGaAs sensors’
built with InGaAs focal-plane arrays
p-type zinc through a diffusion mask
passband is admitted.
(FPAs) are rapidly eclipsing other seninto an n-type InGaAs substrate.
Indium antimonide (InSb) FPAs have
sors in this waveband. The superior
The next step is metal deposition
high quantum efficiency in the NIR
performance of these cameras results
and diffusion into the InGaAs layer to
band, but they require cooling to cryofrom both the FPA design, which has
form ohmic contacts. A total of 81,920
genic temperatures. Their spectral reultra low noise on-chip amplification
cone-shaped indium bumps are desponse is from 1.5 to 5.5 microns, requirand the availability of high quality
ever, don’t always know howInGaAs
to access
posited onto the contact metal pads,
ing that the sensor be combined with a
material in bulk wafers. These
the capability. “The people sensors
who write
making a 320-by-256 pixel array. The
bandpass filter to make a camera that opdeliver excellent image quality
these programs have put in enormously
same number of indium bumps is deerates solely in the NIR band. These facover a wide dynamic range, including
powerful technology. The problem isn’t
that the software needs to move forward.
What needs to be done is for engineers
that are out there to develop skills
through training, and perhaps by better
user interfaces, to use the tools that are
there,” asserted Ken Moore, president of
San Diego-based ZEMAX Development
Corp. “The bottleneck at the moment is
really not the code. It is people learning
how to use the software tools that alDr. Edward Freniere, President,
ready exist.”
Lambda Research Corp.
Usability, therefore, remains at the
top of developers’ “to do” list, with specific tasks including more intuitive
or widget
type of
— we
FiguresGUIs
1. Three images
takenor
through
theglass
backside
of ahave
silicontowafer with an InGaAs camera. Various waveband filters at (a) 1000 nm, (b) 1050 nm,
and (c) 1100
and a greater degree of automation.
Vi-nm. write new software that takes that into
sualization, CAD interoperability, and
account.”
Photonics Tech Briefs, May 2003
the capability to address new IIa
and innovThere is some debate on the value www.ptbmagazine.com
of
ative technologies are interrelated issues
visualization and to what degree it is necthat will also continue to be dealt with in
essary for optical design software packthe next generation of offerings.
ages. Some believe that visualization is
often requested because users trained in
mechanical and electrical engineering
are comfortable with CAD software and
its reliance on imagery during design.
“Optical design is a very different kind of
discipline as the numerical tolerances in
optics are much tighter than they are for
most mechanical design problems,” said
Moore. “You simply can’t define things
visually until it looks right. You’d be off
so far that the optical system would never
even come close to working.
“The first thing people coming in from
other disciplines have to learn,” continBob Hilbert, President/CEO,
ued Moore, “is that optical tolerances are
Optical Research Associates
five or six orders smaller than they are
used to using, which implies a much
“Twenty years ago people were happy
higher level of precision required in not
just to have software to do the calculaonly the optical model, but also how the
tion. Now users want interface,” pointed
program deals with describing optical
out Rich Pfisterer, president of Photon
components. That’s why we have a rather
Engineering in Tucson, AZ. “They want
different sort of numerical view of optical
visualization, buttons to press, and diasystems rather than a visual, human-perlogues to put numbers in. As customers
ception type view of the system.”
change, we have to change our software.
Regardless of the degree of visualizaAlso, as technology changes — if sometion pursued by a particular vendor,
one comes out with a new light source
most expect it to have a greater impact
www.ptbmagazine.com
Photonics Tech Briefs, October 2004
New Products
In every issue of PTB,
New Products pages offer
information on a wide range
of recently introduced products.
Everything from lasers, light
sources, and fiber optics,
to cameras and other imaging
products are included. Also
covered are:
- Detectors & Sensors
- Test & Measurement
- Optical Components &
Systems
New Products
IR Camera Software Toolkit
Product of the Month
MEMS 3D Dynamics Analyzer
The MMA-300 from Polytec, PI (Auburn, MA) is an integrated laser Doppler vibrometry and stroboscopic video microscopy system for full-field 3D characterization of MEMS
dynamics. The system combines the award-winning MSV-300
scanning laser vibrometer, which maps out-of-plane vibration, with the new PMA-300 planar motion analyzer that simultaneously measures in-plane motion. Advantages of both
techniques are exploited including accuracy, speed, and
broad application of laser Doppler together with video microscopy’s ability to measure in-plane motion of virtually any
surface. Applications include MEMS, MOEMS, telecom and light-projection micro-mirror arrays, gyroscopes, micro-machines, and micro-sensors.
For Free Info Visit http://info.ims.ca/2230-200
Indigo Systems (Goleta,
CA) introduces RTools™,
a comprehensive software suite made up of
several easy-to-use, stand-alone modules (RDac, RCal,
RView, and REdit). Developed to meet the rigorous
demands of research engineers and scientists, the software toolkit is designed to acquire, radiometrically calibrate, process, analyze, and archive data from advanced, digital infrared (IR) imaging systems. The kit
provides advanced IR camera users with the capability
to realize spatial, temporal, and spectral radiometric
data in units of absolute or contrast radiance, irradiance, radiant intensity and temperature.
For Free Info Visit http://info.ims.ca/2230-201
UV IQ Laser
Diode Module
UV LED Array
Diode Laser
Systems
Power Technology’s
(Little Rock, AR)
higher power ultraviolet IQ (Instrument
Quality) laser diode
module yields up to 10mW of UV output at 375
± 5nm. The unit has a PID temperature controller
and precision current source making it suitable for
a variety of applications requiring stability of
power, temperature, and wavelength. Features include adjustable focus, quality glass optics, and optional beam expanding optics. It is available with a
circularized beam or with standard elliptical output, and operates in CW mode or with analog or
TTL modulation.
Opto Technology (Wheeling, IL) has added the
395nm UV LED array to its
Shark product line. Using
50 die in a TO-66 package,
the LED achieves 300mW of
optical power from a single
package. The OTLH-0360UV has a peak wavelength
at 395nm with a radiant flux of 300mW when driven
at a maximum peak current of 300mA. The UV
Shark package offers a standard half max viewing
angle of ±54 degrees. Collimating optics and custom
lenses available. Applications include medical diagnostic, adhesive curing, chemical detection, and
document checking.
IPG Photonics’ (Oxford, MA) DLR series of fiber pigtailed
960 nm direct diode
laser systems feature a three year warranty, output
powers >100 W, air-cooled operation, compact
monolithic design, and reliability over a wide
range of ambient conditions. These units have a
diode lifetime >100,000 hours, wall-plug efficiencies >30%, and are available with a range of SMA
connectors, fiber diameters, and lengths. The
lasers operate in a continuous or pulsed mode on
a standard 110/220-volt line. Applications include
soldering, plastic welding, heat-treating, sintering,
and medical applications.
For Free Info Visit http://info.ims.ca/2230-202
For Free Info Visit http://info.ims.ca/2230-203
For Free Info Visit http://info.ims.ca/2230-204
Butterfly Telecomm
Mount
3-CCD Camera
Laser Beam
Profiler
The HS501 Butterfly
Telecomm Mounts from
Micro Laser Systems
(MLS, Garden Grove,
CA) accommodate any butterfly packaged, pigtailed
device such as lasers or semiconductor amplifiers.
Any device with two pigtails can be used. Users can
easily configure the mount for any wide variety of
pin configurations with or without thermoelectric
cooling. Metric and English hole spacing is provided to secure the mount. MLS’s CP Series of
Diode Laser Drivers and CT15W Thermoelectric
controllers make a complete system for controlling
any device. Mounts are also compatible with ILX
and Newport drivers.
R e d l a k e ’s ( S a n
Diego, CA) MS3100
high-resolution 3CCD camera acquires three channels of 1392 x 1040 (4.3 million pixels) images for
applications such as microscopy, medical/scientific
imaging, machine vision, electronics, pharmaceuticals, remote sensing, and robotics. Features include
Camera Link, frame rates up to 7.5 fps, multi-spectral
configuration options, smart camera features, and
analog preview. Two spectral configurations are available; RGB for high quality color imaging and colorinfrared for multi-spectral applications. A common
aperture and accurate alignment provide true color
fidelity and optimum image quality.
Spiricon (Logan, UT)
offers the IBP-5000YAG high-power industrial beam profiler
for Nd:YAG lasers.
Consisting of a beam
sampling head that directs a small portion of
the high power laser to a CCD camera for measurement, it profiles beams up to 5kW and 30mm diameter (45mm clear aperture), logs critical laser properties, and provides electronic “mode burns” of the
intensity profile in real-time 2D or 3D displays. The
portable head can be moved from laser-to-laser to
keep the entire shop operating at peak productivity.
For Free Info Visit http://info.ims.ca/2230-205
For Free Info Visit http://info.ims.ca/2230-206
For Free Info Visit http://info.ims.ca/2230-207
Picometer Resolution Spectrometer
Ceramic Adhesive
Six-Axis Stage
McPherson’s (Chelmsford, MA) well-equipped spectrometer with
2-meter focal length and
double pass/double dispersion features provides
nominal 5-picometer resolution or better. The instrument features multiple entrance and exit ports, high
precision wavelength drives, echelle, and oversize
grating mounting capabilities. The oversize grating
has almost 40% more area, achieving faster f/number
and more throughput. The grating can rotate
through an auxiliary 20° resulting in extension of the
wavelength range. For the 1200 g/mm grating, the
high wavelength changes from 1300 nm to 1575 nm;
an increase of more than 20%.
Ceramabond ™ 685N from
Aremco Products (Valley
Cottage, NY) is a single part,
dispensable, zirconium silicate based adhesive and
sealant system that bonds to
a variety of ceramics including zirconium oxide, zirconium silicate, and aluminum oxide. It also bonds to
metals such as brass, copper, stainless steel, and galvanized and plated steels. This water-dispersible paste
contains no asbestos or volatile organic compounds.
After curing, it exhibits tensile-shear strength of 500
psi, linear shrinkage of <2%, and exceptional chemical, moisture, and thermal shock resistance. Maximum temperature resistance is 2500 °F.
The APT six-axis stage
from Melles Griot
( E l y, U K ) u s e s a
patent-pending mechanism for multi-axis
positioning. Guided
alignment linkage pin (GALPin™) technology combines resolution and friction- and stiction-free performance of flexures with increased travel and compact construction of bearing rails. The 17 APT 600
stage uses modular interchangeable manual differential or stepper motor actuators on all axes. With
half the typical footprint of flexure devices, it offers
12-mm of linear travel. The benchtop devices have increased electronic bandwidth, synchronous movement, and internal analysis capabilities.
For Free Info Visit http://info.ims.ca/2230-208
For Free Info Visit http://info.ims.ca/2230-209
For Free Info Visit http://info.ims.ca/2230-210
14a
www.ptbmagazine.com
Photonics Tech Briefs, July 2003
- Vibration Control &
Positioning Equipment
- New Software Packages & Upgraded Programs
E-mail a product release and digital image, or send it via
regular mail with a color slide, print, or transparency.
In every issue, one new product is also named PTB’s
Product of the Month — a new product with exceptional
technical merit and practical value. Accordingly, each Product
of the Month is a nominee for PTB’s Annual Readers’ Choice
Product of the Year Awards. Separate submissions are not
accepted for Product of the Month or PTB’s Annual Readers’
Choice Product of the Year Awards.
over ➩
2005
Photonics Tech Briefs
More
Functionality
Than Three
Smart Cameras
What is a Faraday optical isolator and how does it work?
A
t high powers optical feedback can
damage or disrupt the operation of a
laser system. To reduce this feedback, an
optical isolator can be inserted into the system. Faraday optical isolators (based on
the Faraday effect) are passive unidirectional, nonreciprocal devices that utilize
National Instruments Compact Vision
System offers more processing power,
camera options, and I/O for your
inspection needs.
Request a brochure and evaluation
software today. Visit ni.com/info
and enter napu2g.
888-280-5761
Traditional
NI CVS 1454
Smart Camera
Configurable
Vision Builder for
Software
Automated Inspection Available
Programmable
LabVIEW
Software
Real-Time
Not Available
Typical
Processor
Performance
883 MIPS*
60-360 MIPS*
Digital I/O
Channels
29
2-20
Cameras
up to 3
1
Resolution
up to 1300x1030
640x480
Frame Rate
up to 100 fps
30 fps
Memory
128 MB
16-64 MB
Mix Color and
Monochrome
Inspection
yes
no
Operating
Temperature
0 to 55 ˚c
0 to 45 ˚c
Base Price
$2,995
$3,295
Figure 1. Example of a broadband Faraday optical isolator, Del Mar Ventures’ model:800B(TGG).
the phenomenon of magneto-optic rotation to isolate the source and protect the
laser oscillator from reflections in an optical system. In other words, they basically
act as an optical diode allowing the propagation of light in only one direction.
Faraday isolators (see Figure 1) typically
consist of a Faraday rotator, two polarizers,
and a body to house the parts. The Faraday rotator, in turn, consists of magnetooptically active optical material placed inside a permanent magnet (Nd-Fe-B).
In the Faraday optical isolator shown in
Figure 2, the magneto-optical rod (located inside the Faraday rotator) is cut
from glass (MOS-10) polished to flatness
of λ/10, and has parallelism better than
10 arc seconds. It is anti-reflection coated
with residual reflection <0.2% (each
side) in the 765-835 nm range. The polarizers are air-spaced Glan prisms made
of calcite. Entrance and exit faces of polarizers are anti-reflection coated with
residual reflection of <0.3% in the range.
Polarizer transmittance is >98%. This
gives a total transmittance of better than
85% for the isolator.
Laser light (polarized or unpolarized)
enters the input polarizer (P1) and is
linearly polarized to 0°. Next, the linearly polarized light enters the Faraday
rotator rod (magneto-optical rod). The
plane of polarization rotates as the light
propagates along the axis of the rod.
The Faraday rotator is tuned to rotate
the plane of polarization by 45°.
(Changing the position of the rod allows
tuning over a wavelength range from
765-835 nm.) The light then passes
through the output polarizer (P2)
whose transmission axis is also at 45°.
Any back reflected light re-enters the
isolator through the output polarizer
and becomes polarized at 45°. The back
reflected light then passes through the
Faraday rotator, which produces another
45° of rotation, and is now polarized at
90°, or horizontally, before being
stopped by the input polarizer, still at 0°.
Thus, the laser is isolated from its own reflections that may occur in the application part of the optical set.
This information was contributed by Sergey
Egorov for Del Mar Ventures, located in San Diego,
CA. For additional information, contact Andy
Carson, product engineer, at (858) 481-9523 or
andy.dmv@femtosecondsystems.com. Visit Del Mar
Ventures online at www.femtosecondsystems.com.
*MIPS: Million Instructions Per Second
© 2004 National Instruments Corporation. All rights reserved.
Product and company names listed are trademarks or trade
names of their respective companies.
For Free Info Visit http://info.ims.ca/3060-853
Figure 2. Components in a typical Faraday optical isolator include input (P1) and output (P2) polarizers and a magneto-optical rod located in a holder (1), which is kept in place by a fixing screw (2).
www.ptbmagazine.com
Photonics Tech Briefs, November 2004
Q&A Column
Cover Art
This column provides PTB readers
with a means of obtaining answers to
their pressing technology and design
questions. Each month, an engineer
from the relevant field addresses a
different topic. Answers may be
accompanied by a short biography of
the engineer. Questions are selected
based on reader submissions and/or
a topic from the Technology Focus
column of the PTB editorial calendar.
Contact the editor for details.
Full-color photos or computer-generated images are welcome
for consideration as PTB cover art. To be considered, artwork
must be an innovative, original image that portrays a new product
or supports other contributed editorial materials, such as a
feature article.
The image may depict an application, the product itself, or a
model of an object in bright, vibrant color. Special background
treatments and lighting techniques may be used to highlight the
subject. Contact the editor for accepted formats in which to
submit cover art.
July 2004
0603
PTB Cover
5/20/03
10:44 AM
Page 1
June 2003
May 2004
January 2004
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d Winners .........
....................2a
...........................
ers’ Choice Awar
..4a
2002 PTB Read
...........................
...........................
h ..................
of the Mont
3D Parts .........
Technologies
Microscopic
............6a
y for Making
na ..................
graph
Anten
e
-Litho
-Waveguid
Inverse Tomo
........................7a
ations in a Beam
py ..................
Beam Aberr
a
n Spectrosco
Correcting for
..........................8
Probes for Rama
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as
.........
laries
s ..................
a
Metallized Capil
voltaic Array
.........................9
ow Solar Photo
...........................
a
Advanced Rainb
Applications
........................10
Automotive
rn Matching
Sensors for
2a
Thermal Load
, and Color Patte
.........................1
Pattern, Color
.........
for
.........
are
..14a
in QWIPs .........
PC-Based Softw
Trapping Light
...........................
for
.........
ctors
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Metal Side Refle
...........................
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m
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page 14a.
New Products....
e.co
Cover photo
ic Products,
courtesy of Photon
see
com
azine.
ptbmag
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See the Photonics Tech Briefs Editorial
Calendar for submission deadlines.
View a PTB Media Kit containing the
editorial calendar online at:
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Submit all materials for editorial
consideration in Photonics Tech Briefs to:
Ashli Barbarito
Editor, Photonics Tech Briefs
E-mail: ashli@abpi.net
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