New at LINOS: Optem™ Zoom Lens

optolines
No. 15 | 3rd Quarter 2007
Trade Journal for Opto-mechanics and Opto-electronics
New at LINOS:
Optem™
Zoom Lens
LINOS and Qioptiq are extending their
cooperation further: LINOS is taking
over the European marketing of Qioptiq
Imaging Solution | Page 7
adjust.x™ – robust and stable
The new mirror mount
Holographic tweezers
Use of light modulators in microscopes
Moems – attractive components
Innovator for optical applications
New: practical fork clamp
Helpful aid for assembly when space is tight
Editorial
Content
INSIGHT
Awarded: The “Golden Microbench” |
19th Goettingen City Run |
Measurement 08 | Page 3
INNOVAS
Now available: The new mirror mount –
adjust.x™ | Page 4
Dear readers,
INNOVAS
LINOS service for users: TracePro®
Training program | Page 6
Synergies are increasingly emerging as a
result of the takeover of LINOS into the
­Qioptiq Group. This is now also visible
from the outside. The LINOS logo carries
the ­subtitle of “A Member of the ­Qioptiq
Group”.
INNOVAS
In LINOS European Marketing:
Optem zoom lenses for industrial
image processing | Page 7
It is decisive that we can offer our customers
from research and industry a wider range of
products now after the consolidation. Our
corporate group grew to 144 researchers and
developers and 2,200 employees on three
continents active in the fields of promising
optical technologies.
Therefore, starting with this edition of
optolines we introduce Qioptiq sites to
you, beginning with our partner in Asslar
­(Germany).
We thank the Fraunhoferinstitut fuer
­Photonische Mikrosysteme in Dresden and
the Institut fuer Technische Optik (ITO) in
Stuttgart for their interesting and relevant
contributions. It pleases us and confirms our
activities that LINOS products are involved
in the further development of pace setting
­photonics in recognised research sites.
CHECKUP
Qioptiq in Asslar: From small series
to complex components | Page 8
RESEARCH
Holographic tweezers – Using light
modulators in microscopes |
Page 10
PARTNER
Innovators for Optical Applications –
MOEMS | Page 14
INNOVAS
New: Practical fork clamp makes
assembly more flexible | Page 18
We wish you lots of enjoyment reading our
new autumn edition,
Bastian Dzeia
Product manager
LINOS Goettingen
2
LINOS LIVE
“International Infrared Spectroscopy
Workshop” in Greifswald 2007 |
Book tip | Exhibition Sneak
Preview 2007 | LINOS Editorial Team |
Legal Information | Page 19
optolines No. 15 | 3rd Quarter 2007
Insight
“Golden Microbench 2006” Award
Annual Distributor training in Goettingen
Measurement
Competence
Goettingen 2008 in the Centre
On February 20th and 21st Goettingen will be for
the second time the global centre of metrology. The
“Measurement08 enabling processes” is taking place
in the Lokhalle. The high-tech exhibition is organized
every second year by the Measurement Valley association. With reference to the Silicon Valley, in 1998
Goettingen-based companies joined their competences
in the fields of optical and tactile metrology, weighing
technology, climate registration, air and space travel
and healthcare. The association is now supported by 37
companies from the region. The University of Goettingen and the State University for Applied Sciences and
Art (HAWK) also take part.
Distributor Training in Goettingen, Germany, June 2007.
In June it was our pleasure to announce the winner
of the „Golden Microbench 2006“, Opto Science
(Japan). During our distributor training we had the
honour to hand out the award to Dr. Tsukio Ideta:
An original Microbench Holder 30, gold plated and
placed on a representative acrylic mount for the
“Best Distributor 2006”. You might ask yourself: Why
a “Golden Microbench”, and why this award anyway? We have good reasons and are proud of them:
The Microbench is a product group, designed almost
forty years ago, constantly developed, with guaranteed full backward compatibility to even the first part
produced. It reflects the LINOS philosophy: Reliability
and performance at the highest level available. In
times of call centers and “support services” trying to
get their customers out of their way, we invest a lot
in keeping up the best service for our customers. Consequently, we train our distributors in a regular manner to keep their knowledge about our products at
Dr. Tsukio Ideta (Opto Science, Japan) receives the
“Golden Microbench 2006” from Andreas Haedrich
(Business Unit Manager Catalog).
highest levels. We decided to honour our distributor
of the year to reflect how happy and proud we are
about our international group of highly skilled representatives. We want to take this opportunity to thank
Opto Science again for a very fruitful cooperation and
we wish good luck for the race in 2007!
LINOS runners in terrific places
LINOS hits the ground running at the 19th Goettingen City Run
Over 1,300 starters ran, perspired and snaked their
way through Goettingen city centre on 18th July. 20
LINOS runners (divided into five groups) also took
part in the five kilometer race. The best LINOS team
occupied the ninth place in a total of 152 company
teams. With a sensational time of 20 minutes and
12 seconds, David Kramer (as in the previous years)
was the fastest LINOS runner. The best placed
woman from the LINOS starting field was Christina
Lips with a time of 29 minutes and 47 seconds. The
runners were supported by lots of LINOS fans, who
cheered the runners on over the course cheerleader
style and provided the best motivation. The sporty
LINOS employees are already looking forward to
next year: 2008 is the 20th anniversary and special
highlights are awaited.
Cooperation is the Measurement Valley’s main
concern.
The exhibition where regional and national companies
present their products and services is accompanied by
an academic congress. The focal themes of numerous
lectures and workshops with a high degree of participation are “imaging sensor technology”, “fluorescent
metrology”, “optical coherence tomography”, and
“optical fluid mechanics”. In addition, contributions are
expected in the subjects “optical production metrology”, “bioanalytics, biosensors and molecular reproduction”, and “data analysis and modelling”.
As the organizer of the Measurement 2008 exhibition,
the Measurement Valley corporate association offers
the opportunity of making direct contact with the leading companies and latest developments in industry.
www.measurement08.de
www.measurement-valley.de
The LINOS team in front of Goettingen’s landmark –
the Gaenseliesel fountain.
Measurement06.
>Contact:
[email protected]
No. 15 | 3rd Quarter 2007 optolines
3
Innovas
Now available: the new mirror mount
™
Robust and stable: adjust.x
The new LINOS mirror mounts adjust.x™, announced in the previous edition of optolines, are now available.
The robust, stable holders lead quickly and precisely to the desired aim and also represent a real alternative to
comparable products in terms of costs.
The first prototypes of adjust.x™ were presented by LINOS at this year’s LASER exhibition in Munich, triggering a very positive
response from the public. With the
adjust.x™ LINOS offers a product, which
holds its own in terms of price with those
of market partners while also displaying
special quality characteristics. In particular,
the long-term stability of the adjust.x™ in
optical structures fulfils the high demands
of research and industry. In addition, the
minimal backlash of the fine adjustment
screws ensures precise adjustments.
“Small” or “Medium”
The new LINOS mirror mount adjust.x™ piqued the
public’s interest at the LASER exhibition in Munich.
Andreas Haedrich from LINOS Goettingen on the
exhibition booth.
Easy to identify on adjust.x™ “small” (front): the precise fine thread screws.
The mirror mounts adjust.x™ are available in sizes “small” and “medium” for
beam heights of 1" and 2", respectively.
“Small” is available for 0,5" and 1" optics,
“Medium” for 1" and 2" optics. Both are
also available with plain front plates. The
customer can choose between two variants: fine adjustment screws on the right
or left. As with the Lees™ mirror mounts,
the construction is made of a solid base
plate and a mounting plate; these are
produced from a high-strength aluminium
alloy. The wide bottom of the base plate
provides a very stable assembly on optical
tables and assembly columns, contributing
to the adjust.x™ mirror mounts very low
sensitive to vibration.

>Contact:
[email protected]
4
optolines No. 15 | 3rd Quarter 2007
Innovas
Free of Play, long term stable
Equipped with three fine adjustment
screws with 0.25 mm threading
(100 TPI), both angle adjustment and
a Z-translation are possible with the
adjust.x™. The combination of stainless
steel spindle and brass bushing ensures
even and true operation. The closest possible production tolerances provide adjustment which is backlash free and long term
stable. The spindles can be finely adjusted
using the provided Allen knob.
Adjustment is smooth, ultra precise and exact –
­Stefan Doering from LINOS Goettingen coordinated
the product development of adjust.x™.
Mirror mounts set at an incline: the adjust.x™ series
is compatible with Lees™ assembly columns and
indexers.
Compatible with Lees™
The adjust.x™ series is completely compatible with the established Lees™ mirror
mounts and can be used together with the
Lees™ Riser Base mounting columns and
the Lees™ Indexer, the mounting column
with removable top.
Versions and Item Numbers
adjust.x™ small,
right hand
adjust.x™ small,
left hand
adjust.x™ medium,
right hand
adjust.x™ medium,
left hand
G03 6620 000
G03 6630 000
Plain plate
G03 6600 000
G03 6610 000
for 0.5" optics
G03 6601 000
G03 6611 000
for 1" optics
G03 6602 000
G03 6612 000
for 2" optics
G03 6621 000
G03 6631 000
G03 6622 000
G03 6632 000
Summary
The adjust.x™ from LINOS covers the
entire usage spectrum from standard to
ultra-precise and feels comfortable in both
research and industry. 
Fokus on adjust.x™
•Very good price-performance ratio
•Precise adjustments
•Robust, solid and stable
in the long term
•Flexible in everyday use
No. 15 | 3rd Quarter 2007 optolines
5
Innovas
LINOS service for users
®
TracePro training program
New impulse for optical designers: TracePro® seminars train new and experienced users in finding solutions
for their complex construction and analysis projects. Professional TracePro® trainers with a strong applicational
background assist unravelling your powers using this very versatile software.
Training courses for the TracePro® optical
software support current and potential
users in their optical construction and
analysis tasks. Discover the ability and
versatility of Trace-Pro®, get the maximum
benefit from your investment, and benefit
from the technical and industry knowledge
of the TracePro® trainers.
TracePro® is a flexible and powerful ray
tracing software. It is based on ACIS®, the
industry standard CAD core with 3D functions used by various CAD software manufacturers. It represents intensity structures
in candela and calculates the lighting on
any surface. TracePro® models any type of
surface, and every surface can be defined
as a light source. TracePro® is a modern,
easy-to-use graphical interface between
CAD and optics design software.
Make your reservation
Make your reservation for the TracePro®
training now. There is one date remaining
in Germany this year:
•10th to 14th December 2007: Passau
(language: German)
The TracePro® software tool
TracePro® is an extensive and versatile tool
for fantastic representation of the dispersion of light in imaging and non-imaging
opto-mechanical systems. The models are
generated via import from lens construction programs, CAD programs or through
direct programming of the solid geometry
in TracePro®. Source rays diffuse through
the model, which causes parts of the
luminous flux of every ray to be subject to
absorption, reflexion on smooth surfaces,
transmission, fluorescence and dispersion.
Model and ray tracing allow, amongst others, the analyses of:
• Light dispersion in lighting and image
formation systems
• Stray light, diffused light, and aperture
dispersion
• Capacity, loss and system penetrability
• Absorption of luminous flux and performance through surfaces or volume
media
• Light dispersion in biological tissues
• Polarisation effects
• Fluorescence effects
• Birefringence effects 
Simulation of light dispersion of a ring light.
Training course is composed of three
theme blocks over a total of five days:
Day 1 + 2:Lighting analysis
Day 3: Diffused light analysis
Day 4 + 5:Makro programming with
scheme.
These theme blocks can be booked
­individually or as an entire package.
>www.linos.de
Note:
You will find a clear version comparison on the LINOS website:
> Shop: Optik > Optiksoftware >
TracePro®
6
optolines No. 15 | 3rd Quarter 2007
Innovas
In LINOS European marketing:
™
Optem zoom lenses for
­industrial image processing
LINOS and Qioptiq are further extending their cooperation: LINOS is taking over the European marketing of
Qioptiq Imaging Solution, becoming one of the most important suppliers for zoom lenses in industrial image
processing.
nection also makes it possible to adapt
the visual field. Modules from 0.38 x up
to 2.0 x magnification are available. In
addition, the optical path can be deflected
here (0° / 90° / 180°).
Zoom module
The zoom module defines the actual zoom
faktor. Modules with a zoom range of 7:1
to 16:1 offer the flexibility necessary to
carry out individual adaptation for every
use. An incremental readout mechanism
provides high precision and reproducibility. The zoom module contains a variable
aperture (motorization optional).
In LINOS marketing: Optem™ zoom lens for industrial
image processing.
Besides, of course, good imaging performance, inspection tasks in industrial image
processing place further demands on a
lens: the rapid and simple a variability of
the object field.
The lenses of the Optem™ series fulfil
these demands to the letter. The Optem™
zoom systems are constructed in a
modular way enabling versatile and flexible usage. The zoom system consists, in
essence, of the TV connection, the zoom
module, and the function module.
TV Connection
The TV connection ensures the camera is
in the right position at the right distance
to the lens. The selection of the TV con-
Function module
The function module is the actual reproducing unit. A wide range is available
here from the standard module, which is
focussed on the operating distance, over
a coaxial lighting system to infinite trimming lens module. The modules all have
an M 26 x 36 T connection, accepting both
Optem™ and Mitutoyo lenses. Using an
adapter, Olympus and Nikon lenses can
also be connected.
Fetura is a motorised 12.5:1 zoom module, which moves its entire zoom area
about 10 x faster than conventional motorised zooms. As a result, in many ­inspection
tasks a significantly higher capacity is
achieved. Fetura is also equipped with an
onboard microprocessor, which supervises
the precise setting of the enlargement and
centering. This ensures that the inspection
system always moves to the correct position and shows the right display window.
Even more important is the robust, optomechanical design of the Fetura ensuring
a life span of more than one million zoom
cycles. OEM integration is simple, and
­flexibility is maintained through modern
interfaces and user-friendly programming.
Summary
Optem™ zoom lenses can be used anywhere where a high imaging performance
combined with an alternating object field
is demanded. Optional motorisation and
coaxial lighting systems round the system
into a universal vision system for today’s
inspection tasks. 
Non-modular systems
LINOS also offers a compact sevenfold
zoom lens which controls focus and zoom
using a DC or stepper motor.
Anyone who requires a very rapid zoom
lens for rapidly change object field sizes
will find the appropriate product in the
newly developed Fetura zoom module.
>Contact:
[email protected]
No. 15 | 3rd Quarter 2007 optolines
7
CHECKUP
Qioptiq in Asslar (Germany)
From small series to
complex components
With Qioptiq Asslar customers dealing with endoscopy find a partner for demanding solutions: through highquality optomechanical microsystems. Among the many top-class optical companies in the region of Wetzlar,
Qioptiq has a distinct core competence in micro-optics for medicine and sensor technology, telecommunication,
and optical system technology. During a visit in July of this year, the optolines editorial department convinced
itself of the long tradition in miniaturized optics fabrication and the new objectives deriving from it.
Two compact lenses for endoscopes, shown by Michael Reinl, Project Manager at Qioptiq.
The site in Asslar near Wetzlar is part of
the Qioptiq group of companies in Germany. The company, which has traded
under the name of Thales Optische
Systeme GmbH since 2001, dates back
to Neeb Optik founded in 1952 by Otto
Neeb. The company developes and produces precision optics and optical systems for
over 50 years. In doing so, Qioptiq Asslar
focuses mainly on customers from medical
8
technology: The product spectrum ranges
from diameters of 0.4 mm to 50 mm
diameter optics. A particular speciality is
the smallest achromat of 0.6 mm diameter. “Few companies can produce these
assemblies,” emphasises Yvonne Franz,
sales and marketing. Achromat sizes up to
3 mm from Qioptiq Asslar are listed in the
LINOS catalogue.
Katharina Fritzler in lens assembly.
Glad to be cooperating
On one hand, Qioptiq in Asslar offers
a standard program, which is intended
to be further expanded to catalogue
range within the Qioptiq group. “What
our customers particularly value are our
individual solutions, flexible production
of samples, and orders in manageable
amounts,” underlines Martin Hofmann,

optolines No. 15 | 3rd Quarter 2007
CHECKUP
Sales & Marketing Manager of Qioptiq
Asslar. The component and project business (including assembly of all the modules
and systems) is tailored individually to the
customers needs. Here, the 70-man team
from Central Hessen, runs its own apprentice scheme. The graduates enhance the
unique micro-optic capability of the company. “With new products and equipment,
especially from medical technology, we
are incorporated from the very beginning
and design the solution together with the
customer,” explains Martin Hofmann. 
The product portfolio
of Qioptiq Asslar
•Endoscopy optics
• Spherical lenses and achromats
• Optical design
Interferometric characterization of lens surfaces.
• Standard lenses for photography
and projection
• Microlenses
• Customer specific components and
systems
Public relations: Norbert Henze from LINOS Goettingen (right) visited Martin Hofmann,
Sales & Marketing Manager, and his employee Yvonne Franz, Qioptiq Asslar.
>Contact:
www.qioptiq.de
No. 15 | 3rd Quarter 2007 optolines
9
RESEARCH
Light modulator applications in microscopes
Holographic tweezers
By T. Haist, S. Zwick, M. Warber, W. Osten, Institut fuer Technische Optik (ITO) Stuttgart
Are holographically controlled tweezers superior to conventional tweezers? The ITO Stuttgart is currently looking
into this question as part of the BMBF joint project AZTEK. Together with Holoeye AG and TILL Photonics GmbH,
different possibilities to use light modulators in microscopes are being investigated.
The contactfree movement and handling
of microscopic-objects is of decisive importance for a multitude of future, innovate
applications in the areas of biomedicine,
microsystem technology and microchemistry. Two properties of lights are used
to optically carry out the appropriate
manipulation: On one hand the energy of
the light is used in so-called laser scalpels
to cut, fuse and destroy a huge variety of
materials. On the other hand the rather
unknown possibility exists of achieving
an momentum transfer using light, thus
harnessing forces. Through the change of
momentum which laser photons experience during the deflection to an object,
microscopic objects can be captured and
moved in the focus of a laser. This method
is used by optical tweezers.
When combined, both methods can be
used to perform extensive manipulations
in science as microtechnology and nanotechnology applications. These methods are
predominantly used in life science e.g. in
cell biology. They enable the biologists to
grasp, separate and move cells and induce
their fusion, division or destruction.
In conventional systems, capturing and
cutting light fields are moved mechanically
(generally with the help of mirrors or acustooptic deflectors). These systems reach
their limits with simultaneous manipulation
of several cells or three-dimensional control: The experimental composition quickly
becomes very complex and inflexible with
10
Fig. 1: Computer controlled holographic tweezer system to manipulate many objects in three-dimensions
based on a ZEISS Axiovert 200M microscope, a Holoeye light modulator and the LINOS Microbench system.
increasing numbers of traps and processing
spots. At this point, holographically controlled s­ ystems offer a solution: By using
a high-resolution dynamic light modulator as a hologram in the Fourier plane of
the object plane (fig. 2), a virtually infinite
number of traps can be generated. These
can be moved three-dimensionally, completely independent of one another. The
mechanical design here remains extremely
compact. Moving elements are avoided.
Control of the spots generated is possible
with the precision of a few nanometers.
Computations
In real-time video the computation of the
holograms takes place (even for large trap
numbers). This is achieved on conventional
PCs by carrying out the complete hologram computation on the graphic card

optolines No. 15 | 3rd Quarter 2007
RESEARCH
of the computer. The benefit here is the
fact that the performance of conventional
graphic cards, such as those used for video
games, is significantly above higher than
the performance of the PC main processor
(CPU) for parallel tasks (approx. by a factor of 10). With a Nvidia 8800GTX based
graphics card, for example, 360 complex,
two-dimensional (512 x 512 pixels) Fourier
transforms per second can be computed.
Various algorithms are used for the hologram computation (direct computation,
iterative Fourier transform algorithms).
As part of the BMBF joint project AZTEK,
an add-on module for inverse microscopes
was developed for the Zeiss Axiovert
series. The optical design was carried out
in Zemax. In doing so, a phase-correct
diagram of the Holoeye HEO 1080p
light modulator used must ultimately be
achieved in the pupil plane of the microscope with diffraction-limited performance over the entire field. The system is
connected to one of the two lateral ports
of the Axiovert. When using various microscope objective lenses, care must be taken
to ensure that the entrance pupils vary in
terms of location and size. The module
was realised using the LINOS microbench
system. For applications involving (living)
cells as samples, a 1060 nm fiber-coupled
laser was used. For destructive holographic
processing we use a frequency-tripled
(355 nm) Nd:YAG laser.
Fig. 2: Schematic structure of holographic tweezers. The light modulator (SLM) is in a FOURIER level of the
object. The light field in the object level arises as a result as a Fournier transformation of the hologram
­registered in the light modulator.
Besides three-dimensional movement
and processing in a nanometer scale,
cells can also be rotated and tilted threedimensionally in a targeted and controlled
way. For this purpose, an angular momentum transfer, could directly be achieved
using the polarisation of the light or spiral
phase. However, our experience showed 
Fig. 3: Mechanical and optical design of the add-on module for Zeiss Axiovert microscopes based
on the LINOS Microbench system.
No. 15 | 3rd Quarter 2007 optolines
11
RESEARCH
Fig. 4: Tilting (out-of-plane rotation) of a cell through double-spot technique. The yeast cell in the centre is tilted through the controlled three-dimensional relative
movement of two springs. That the cell is not symmetrical in its rotation can only be seen through the tilt. Accordingly, rotations (in-plane rotations) are also possible.
that a simple multi-spot technique is more
effective. In this case, several traps per cell
are used and moved relative to another
(Fig. 4). As the trap number is not limited
with holographic tweezers this can easily
be realised on the software level.
The high flexibility which can be achieved
with the holographic approach is also
shown in a further modification of the
holographic alignment. Usually cells can
only be aligned three-dimensionally if a
microscope lens with a high numerical
aperture (NA) is used. With a lower NA
the pressure of the light radiation leads
to a “shooting out” of the cell from the
trap. For applications in which a higher
operating distance or larger depth of focus
is required one normally is forced to use
lenses with lower NA (or very expensive
LWD lenses).
We avoid the problem holographically
through the principle of the twin trap,
as shown in Fig. 5. For every object to
be trapped two traps are coded into the
12
hologram. The two traps are at different
depths. The light field of the deeper trap is
reflected through the microscope slide and
overlays the light field of the higher trap.
In this way the object is captured from
two sides effectively, and the strong light
pressure is completely canceld in the axial
direction. A three dimensional alignment is
possible also with low-aperture lenses.
Aberrations induced by the specimen
and dependant on the system, can be
cancelled out simply using the hologram.
The rapid determination of aberrations is
decisive. Different procedures have been
examined; however, a completely automated method which is effectively practicable has still not been realised.
Summary
The advantages and ­disadvantages of
holographic tweezers compared to conventional optical tweezers are:
Advantages
•Simpler mechanical design without
moving mechanical parts
• Simultaneous control of many traps
with high precision in three dimensions
• Possibility of using low-aperture lenses
through twin-focus technique
• Possibility of aberration correction
• Possibility of using alternative alignment
fields (e.g. doughnuts or extensive
fields that are gentle on the cells)
Disadvantages
•Loss of light: the used light modulator
comes from the consumer projection
sector and is not primarily intended for
holographic applications. Considerable
loss of light is the result. Between 10%
and 50% of the light can be effectively
used for alignment, depending on the

modulator used.
optolines No. 15 | 3rd Quarter 2007
RESEARCH
References:
[1] Hayasaki et al., “Optical manipulation
of microparticles using diffractive optical elements”, Proc. SPIE 2778,
P. 229–230 (1996).
[2] Reicherter et al., “Optical particle
trapping with computer-generated
holograms written on a liquid-crystal
display”, Optics Letters, 24, P. 608-610
(1999).
[3] Curtis et al., “Dynamic holographic
optical tweezers”, Optics Communications 207, P. 169-175 (2002).
[4] Reicherter et al., “Fast digital hologram generation and adaptive force
measurement in liquid-crystal-display
based holographic tweezers”, Applied
Optics 45, P. 888-896 (2006).
[5] Haist et al., “Using Graphics Boards
to compute holograms”, Computing in
Science & Engineering – January 2006,
P. 8-14 (2006).
Fig. 5: Principle of stable alignment with low numerical aperture (larger operating distance) using the
“twin trap” technique: Two partial springs are
holographically generated per spring. The red partial
spring is reflected on the dichroite microscope slide
and overlays the green partial spring. The destructive forward-throwing power of an individual spring
is thus eliminated.
From our point of view, holographicallycontrolled tweezers are superior to
conventional tweezers for complex applications. We see a high potential in the
future, particularly in automated applications. 
[6] Zwick et al. “Realisation of a holographic microlaser scalpel using a
digital micromirror device”, Proc. SPIE
6616, P. 6616-0N (2007).
[7] Zwick et al., “Holographic Twin
Traps”, submitted to Optics Letters.
[8] Reicherter et al., “Dynamic correction
of aberrations in microscopic imaging systems using an artificial point
source”, Proc. SPIE 5462 , P. 68-78
(2004).
[9] Reicherter et al., “Advantages of holographic optical tweezers”, Proc. SPIE ,
5143, P. 76-83 (2003).
>Contact:
www.uni-stuttgart.de/ito
No. 15 | 3rd Quarter 2007 optolines
13
Partner
Innovation in optical applications
MOEMS – attractive components
Dr. Steffen Sinning, Fraunhofer Institut Photonische Mikrosysteme in Dresden
Micro-Opto-Electro-Mechanical Systems (MOEMS) are used as active optical devices in a progressively g
­ rowing
number of manifold applications. The most popular utilization in the consumer market is probably the
usage in the field of Digital Light Processing (DLP®) [1], but also in a lot of niche applications MOEMS can be
­implemented in an effective manner. The Fraunhofer Institute for Photonic Microsystems in Dresden, Germany
develops micromirror matrices, which consist of up to 1 million individually deflectable mirrors. These micromirror matrices are usable as a programmable mask for optical applications in the visible to the ultra violet
wavelength range.
The number of applications for laser light
in the ultra violet (UV) range is steadily
growing. The main reasons for that can
be found in the properties of short-wavelength light itself. For instance the critical
feature size in the semiconductor production is, among others, determined by the
wavelength of the light used for exposing
the resist. Structures of the current 65 nm
nodes e.g. require the wavelength to be
193 nm [2], a further demagnification of
the structures can be realized by using
even shorter wavelengths. An additional
effect is the, in comparison to light with
larger wavelengths, higher energy of the
photons and the often smaller ­penetration
depth into materials. Both properties
promote devices using this wavelength
range as ideal tools for ablation und marking with lasers. A further reason for the
frequent implementation of UV lasers is
their availability in the higher and highest
power range.
For many applications it is necessary to
shape the laser beam. Fixed masks often
do not allow for sufficient flexibility. A
common method uses lasers modulated
by acousto-optical modulators to raster
the area to be exposed. The main
­disadvantage is the inherent serial writing method which limits the throughput.
A massive parallelisation is possible with
Fig. 1: Black/white and grey level image created in a test setup using an SLM
(approx. 200 x 200 micro mirrors, respectively).
Micro-Opto-Electro-Mechanical Systems
(MOEMS). Such systems based on micromirror matrices are developed and produced in the attached clean room facilities
at the Fraunhofer Institute for Photonic
Microsystems IPMS in Dresden, Germany.
These spatial light modulators (SLM)
allow, spatially resolved, for modulating
the intensity of laser light in the visible up
to the ultra violet wavelength range. The
micro mirrors can be deflected in an analogue fashion: in the specified range every
arbitrary deflection can be realised. This
allows the direct creation of grey levels
without usage of pulse width modulation.
Figure 1 shows images created with an
SLM in the demonstration setup discussed
below. The free programmability of the
mask and a high image repetition rate,
in comparison with e.g. liquid crystal displays, result in the highest flexibility possible.
Mirror layout
Figure 2 shows a schematic of a mirror
layout. The area of a mirror has a dimension of 16 x 16 µm². The mirrors are suspended by two hinges and can be tilted 
>Contact:
www.ipms.fraunhofer.de
14
optolines No. 15 | 3rd Quarter 2007
Partner
Fig. 2: Schematic of a single mirror.
towards the address electrode by applying
a voltage to this electrode. The inclination of any mirror is thereby independent
on the deflection state of neighbouring
mirrors. The deflection is realised through
electrostatic forces by applying electrical
voltages. The electrical potential n
­ ecessary
for deflecting the mirror is stored in a
DRAM-like cell with support capacitance,
which is located directly underneath the
corresponding mirror. The cell is loaded
during the writing process via an attached
field effect transistor, the closed transistor
then conserves the stored charges in the
cell. A separate charging cell is attached to
every mirror, counter and mirror electrodes
feature a common potential, respectively.
An SLM consists of a number of single mirrors, which are integrated in a rectangular
matrix. Currently two standard configurations are produced at the IPMS. One consists of 256 x 256 micro mirrors resulting in
an active area of approximately 4 x 4 mm².
The larger matrix is built up of 2048 x 512
mirrors and utilises an area of 33 x 8 mm².
The filling factor of the mirror area is
almost 90 %. Figure 3 shows an SLM and
a scanning electron microscope image of a
part of the mirror area.
No. 15 | 3rd Quarter 2007 optolines
Fig. 3: Spatial light modulator. The inset shows a scanning electron microscope (SEM) image of the micro mirrors.
Fourier optical imaging principle
To create shadowed regions a wave-optical
principle is applied: the mirror matrix is
considered as an optical grating, on whose
periodic structure the light is diffracted.
The inclination of the mirror thereby corresponds to the variable “blaze” angle of
the grating. Figure 4 shows the principle.
The light is coupled into the optical path
by a beam splitter and shines on the SLM.
If the mirrors are not deflected (Figure 4 a),
the light is diffracted completely into the
0th diffraction order. In case of deflected
mirrors the light will, depending on the
deflection of the mirror partially to completely, be diffracted into higher orders.
Figure 4 b shows the case where the light
is completely diffracted into the 1st order.
A fixed aperture is positioned in the Fourier plane of the Fourier lens. Light which
is diffracted into the 0th order can pass this
aperture and creates a bright area in the
image plane. Higher orders are blocked,
the case shown in Figure 4 b results in a
Fig. 4: Schematic layout of the Fourier optical imaging principle for (a) nondeflected mirrors and (b)
deflected mirrors.
dark area in the image plane. The distribution of light into the different diffraction
orders changes gradually with change of
deflection of the mirrors, the two cases in
Figure 4 thereby should be considered as

border cases.
15
Partner
Fig. 5: Relation between intensity I of the light in the
image plane and the deflection d of the mirror.
Fig. 6: Intensity profile at the image plane of two
neighbouring regions with deflected and nondeflected mirrors for several deflections d of the mirror
at the border of these two regions. The inset above
shows schematically the deflection of the mirrors.
Fig. 7: „Negative black“ effect: deflecting the outermost fully deflected mirror to above its nominal
deflection dN, increases the steepness of the shoulder at the dark to bright transition.
Defining the deflection d as the stroke
of the mirror edge during deflection, the
intensity I depends on the deflection d as
follows [3]:
optics the transition between the dark and
the bright region is smooth. Additionally
Figure 6 shows the resulting intensity profiles for different deflections of the mirror
on the border between the deflected and
the nondeflected regions. Obviously the
deflection of the mirror determines mainly
the position of the shoulder. By means of
analogue deflection it is possible to position structures on a sub grid of the pixel
raster, whose resolution is given by the
number of grey values. This is related to an
increase of the (virtual) resolution.
For partial compensation of the broadening of the shoulder caused by the Fourier
optics another effect of the analogue
operating mode can be used. Figure 7
summarises simulated intensity profiles of
a bright to dark transition with the shoulder shifted to a sub-pixel grid position (see
Figure 6). If the last fully deflected mirror is
deflected to more than its nominal deflection dN the steepness of the shoulder is
affected but not the position of the shoulder itself.
With the LINOS Microbench system a test
setup was realised (see Figure 8), which
allows the demonstration of the fundamental principle and main applications.
This system uses a green light emitting
diode (LED, wavelength 510 nm) as a
light source. After collimation the light
shines on the SLM, passes through the
Fourier optics discussed above and is then
detected by a camera. Figure 1 shows
images taken with this setup.
(1)
with λ being the wavelength of the used
light source. This relation is shown in
Figure 5. Thereby the nominal deflection
dN is defined as the deflection needed to
reach the first. With this the border cases
in Figure 4 correspond to d=0 and d=dN,
respectively.
With (1) follows for the first minimum:
dN = λ/4. This means that the deflection
of the mirror necessary for creating a dark
region depends on the wavelength λ of
the used light source and increases with
increasing wavelength.
The aforementioned considerations are
related to a uniform deflection of all mirrors. Figure 6 shows a simulated intensity
profile with deflected and nondeflected
mirrors. Caused by the cutting of the
higher diffraction orders in the Fourier
16
Applications
Applying the Fourier optics discussed in
paragraph Fourier optical imaging principle
the SLM can be used as a mask whose
content (image written in the SLM) is
freely programmable with a high repetition rate. This allows for a wide variety of
applications. For example, the SLM is used
in lithography machines which produce
masks for the semiconductor industry.
Likewise a freely programmable mask can
be used as a light source for structured

illumination in microscopy applications
optolines No. 15 | 3rd Quarter 2007
Partner
and for direct exposure in the field of PCB
production.
The analogue deflection of the mirrors
and the possibility to use grey levels allows
further applications in the field of laser
projection.
If all mirrors are deflected by the same
amount the mirror matrix can be understood as an optical grating with adjustable
blaze angle and, as a result of this, diffraction efficiency.
Summary
MOEMS are attractive and innovative
devices which allow novel applications in
many fields. The fabrication defines enormous requirements to equipment and production conditions. An optical setup was
realised with LINOS components which
shows the principle of operation and the
high quality of the SLM produced at the
IPMS.
Literatur
[1] Larry J. Hornbeck: “Digital Light Processing and MEMS: reflecting the digital display
needs of the networked society”, Proceedings of SPIE, redaction 2783 (1996), P. 2-13.
[2] International Technology Roadmap for
Semiconductors (ITRS) 2006,
(http://www.itrs.net).
[3] A. Gehner: “Entwicklung hochaufloesender Flaechenlichtmodulatoren mit
deformierbaren Spiegelanordnungen fuer
die maskenlose Mikrolithographie”, Shaker
Verlag, Aachen (1997). 
No. 15 | 3rd Quarter 2007 optolines
Fig. 8: Photograph and schematic of the test setup.
17
INNOVAS
Makes assembly more flexible:
New LINOS fork clamp
The LINOS fork clamp is made from high-strength aluminium alloy.
The fork clamp utensil is a practical assistant when space is tight.
The light and stable fork clamp supports
flexible assembly of components in combination with the A14 adapter. It works by
the principle of an “Easy Lift System”: A fit
helps to jack the fork clamp hanging onto
the adapter. This allows simple assembly of
the fork clamp in its design, even in tight
spots on optical tables. The fork clamp
is made from a high strength aluminium
alloy and is fitted with a slot hole for M 6
or 1/4” screws for fixing on optical tables.
The A14 adapter offers the possibility to
fix with M6 or 1/4” screws to columns,
­tripod spikes, or directly to components. 
Assembly of the fork clamp – with column 14 on
adapter 14 – on the optical table.
“Easy-Lift-System”: When moving the column the
fork clamp clings to the 14 adaptor.
The dimensions of the new fork clamp.
The A14 adaptor.
>Contact:
[email protected]
18
optolines No. 15 | 3rd Quarter 2007
Linos live
Workshop in Greifswald and LASER 2007
Book Tip
Top-class at the “International Infrared Spectroscopy Workshop”
Handbook of Optical Systems
After the huge success of the first International Workshop for Infrared Plasma Spectroscopy in 2006, the
second meeting in July this year in Greifswald brought
together physicians and chemists from facilities around
the world. As in 2006, LINOS was in attendance with
a marketing team and presented new products from
opto-electronics, optics and opto-mechanics at the
accompanying industry exhibition. Applied spectroscopy methods in the field of medium infrared
for examinations in gas discharges were at
the focal point of the Greifswald workshop.
The scientific program covered all modern
topics of infrared plasma spectroscopy from
basic research to industrial applications. The
workshop covered all types of spectroscopy
in the field of infrared, such as FTIR, ATR, and
absorption spectroscopy with variable diode
lasers, and their various applications for measurements in different gas discharges.
Volume 4: Survey of Optical Instruments
Optical Systems (Band 4)
The state-of-the-art handbook written
by reputed industrial experts gives a
comprehensive introduction in the
principles and the practice of calculation, layout and understanding of
optical systems and lens design.
The authors combine for the first
time theoretical aspects of optical
modeling with applications of practical optical design.
This fourth volume presents a survey of the known different types
of optical systems, based on the
principles of image formation, aberration control,
quality criteria and realization aspects, which are covered in the first three volumes. Starting with the human
eye, binoculars, eyepieces and simple systems, more
complex systems types, such as photographic lenses,
telescopes, microscope systems and projection systems
are discussed, before going on to present aspects of
infrared systems, zoom setups and illumination, as
well as scanner optical systems, medical systems and
spectroscopic arrangements. Finally, more specialized
aspects are treated, including laser beam systems, auto
focus control systems and setups with remote pupils.
Once again, LINOS was completely satisfied
with this year’s LASER exhibition in Munich.
Both the number and quality of customers,
and visitor contacts showed that LINOS covers
important fields of the key technologies in photonics research and industry. The LINOS booth
made impressions through a highly motivated and
friendly team introducing new and also well ­established
products. The atmosphere was spiced up by a professional caricaturist. Many visitors were drawn to the
headup display: At the LINOS booth they could experience the view of a pilot. The headup display projects
important flight information into the field
of view.
Prof. Wolfgang Vioel from the HAWK University of Applied
Sciences in Goettingen looks forward ­seeing his caricature on
the LINOS booth.
LINOS 2007/08
At all the important exhibitions and conferences
Date
Exhibition
Place
More information
03. to 07.11.
Neuroscience
San Diego, USA
www.sfn.org
06. to 08.11.
VISION
Stuttgart
www.messe-stuttgart.de
19. to 23.11.
Methodes et Techniques Optiques pour
l’Industrie
Archachon, France
19. to 24.01.08
Photonics West
San Jose, USA
spie.org
optolines editorial team
Gross, Herbert / Blechinger, Fritz / Achtner, Bertram, Volume 4: Survey of Optical Instruments,
Optical Systems (Band 4), 1. Edition, December
2007, 800 pages, Hardcover, Manual/Reference
book, Euro 298,-, ISBN-10: 3-527-40380-9,
ISBN-13: 978-3-527-40380-6, Wiley-VCH, Berlin
Imprint
“Gone away ...”
In the final editorial stage appointments in the editorial
team meant they were constantly on the move – partly
for professional reasons (exhibitions, international client
visits) and partly for private reasons. Therefore, this edition features a holiday postcard (this is what summer
can look like!) instead of the team photo. The editorial
department is always available to receive any suggestions for improvements or themes.
Herbert Gross studied physics at the University of Stuttgart, Germany, and joined Carl Zeiss in 1982, where has
since been working in the department of optical design.
Since 1995, he has been head of the central optical
design department at Zeiss. In 1995, he received his PhD
at the University of Stuttgart, Germany, on the modeling
of laser beam propagation in the partial coherent region.
Happy holi
days
to the LINO
S team
Publisher: LINOS Photonics GmbH & Co. KG,
Industrial Manufacturing division
Koenigsallee 23, D-37081 Goettingen
Phone +49 (0)5 51 / 69 35-0, www.linos.de
© Concept, layout and production:
BEISERT & HINZ
UNTERNEHMENSKOMMUNIKATION GbR
Prinzenstrasse 21a, D-37073 Goettingen
> Contact: [email protected]
> www.optolines.de
No. 15 | 3rd Quarter 2007 optolines
19
LINOS AG
Koenigsallee 23
D-37081 Goettingen, Germany
www.linos.com
LINOS Photonics GmbH & Co. KG
Koenigsallee 23
D-37081 Goettingen, Germany
Phone +49 (0) 551 69 35-0
Fax
+49 (0) 551 69 35-166
E-mail [email protected]
LINOS Photonics Inc.
459 Fortune Boulevard
Milford, MA 01757, USA
LINOS Photonics Ltd
2 Drakes Mews, Crownhill
Milton Keynes,
Buckinghamshire, MK8 OER, UK
LINOS Photonics France
90, avenue de Lanessan
69410 Champagne au Mont d‘Or, F
Phone +1 (508) 478-6200
Fax
+1 (508) 478-5980
E-mail [email protected]
Phone +44 (0) 19 08 26 2-525
Fax
+44 (0) 19 08 26 2-526
E-mail [email protected]
Phone +33 (0) 472 52 04 20
Fax
+33 (0) 472 53 92 96
E-mail [email protected]