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Marcus Liemen - Business Development Accurion

Marcus Liemen

Business Development



Dr. Peter Thiesen - Senior Application Specialist Accurion

Dr. Peter Thiesen

Senior Application Specialist

Phone: +49-551-9996020


Daniela Bogner - Sales Manager Accurion

Daniela Bogner

Sales Manager

Phone: +49-551-9996013


Linda Thieme - Sales Manager Accurion

Linda Thieme

Sales Manager

Phone: +49-551-9996016


Sebastian Funke - Application Specialist, 2D Materials Accurion

Sebastian Funke

Application Specialist, 2D Materials

Phone: +49-551-999600


Dr. Christian Hoffmann - Application Specialist for Biological Applications Accurion

Dr. Christian Hoffmann

Application Specialist for Biological Applications

Phone: +49-551-9996021


Stephan Ferneding - Chief Executive Officer Accurion

Stephan Ferneding

Chief Executive Officer

Phone: +49-551-999600


Narayana Sharma - Sales and Application Accurion

Narayana Sharma

Sales and Application

Phone: +91-98450 04273


Frank Zuo - Sales and Application Accurion

Frank Zuo

Sales and Application

Phone: +86-21 5017 9099


Dr. Antonio Gonzalez - Service and LB-Application Specialist Accurion

Dr. Antonio Gonzalez

Service and LB-Application Specialist

Phone: +49-551-9996035


Arash Mirhamed - Technical Director Accurion

Arash Mirhamed

Technical Director

Phone: (+1) 408 642 1446


Holger Grube - Service Engineer Accurion

Holger Grube

Service Engineer

Phone: +49-551-9996023




Accurion Online
"FAQ" contains the most frequently asked questions about our products.


Is it possible to upgrade the EP4-BAM to an imaging ellipsometer?

Yes, as it uses the same hardware and software platform. Also an upgrade of a single wave to spectroscopic ellipsometer is possible.

Is it possible to use the imaging ellipsometer as a Brewster angle microscope?

Yes! BAM operation is a "subset" of the imaging ellipsometer. However, applicability of an imaging ellipsometer as a BAM depends on the laser power. We recommend at least 20mW, better 50mW lasers when using the imaging ellipsometer as a BAM is intended.

What laser do I need for my application?

Generally three standard lasers are available (other lasers can be adapted on request): 532nm green laser with 20mW or 50mW and a 658nm broadband laser with 50mW. A blue broadband laser may be available in the future. Following facts should be considered:

a)Due to the coherence of lasers there are disturbing interference rings and lines visible in the images. Those interferences are caused by the camera, analyzer and objective. Especially in the EP3SE those interferences are visible and may also cause a gradient in the maps. So especially for EP3SE a 658nm broadband laser is recommended to avoid interferences.

b)For solid samples a 20mW laser is sufficient because of the high reflectivity (see also What laser do I need for measuring at liquid-air-interface?)

c) The lateral resolution depends on the used wavelength. With a lower wavelength a higher resolution may be achieved. So the 532 nm (green) lasers leed to a slightly better resolution.

d) The camera is most sensitive to green wavelength. For blue and red the sensitivity decreases down to 50% so here a laser with a higher power is required. At 658nm the camera sensitivity is 70%.

Why using Nulling Ellipsometry in the EP4?

There are many different ellipsometry methods. The idea is always the same: analyze how the state of polarization is altered due to reflection caused by the sample. Thus, this information characterizes the sample.

We use nulling ellipsometry for 3 reasons:
a) Nulling ellipsometry allows one to make the image "dark" at a certain region of the sample. If there is a difference in the optical properties of the sample, those other regions are "bright", because the nulling conditions are not fulfilled for those regions. Thus, we get a contrast that may be directly visualized by a camera. This is what we call "real-time ellipsometric contrast".
b) Nulling ellipsometry is very sensitive compared to other methods, thus giving high contrast, especially for very thin films.
c) Nulling ellipsometry offers the ability to measuring in four zones => for isotropic materials, the expected result after rotating a polarizer, compensator or analyzer 180 ° is the same as without rotation. There are four possible combinations of polarizer/compensator and compensator/analyser that give the same result. The advantage of this is that the average is, to a large extent, free of systematic errors.

In principle one could also use many other methods in an imaging system. But this would have several disadvantages: for example in "rotating analyzer" elli, one rotates the analyzer constantly. This
means that the image would be very bright most of the times, and only sometimes it gets a little darker. Thus, the sensitivity is not very high for very thin films. Also, one needs a very high dynamic range camera and very linear camera response. Several images have to be collected and then the final image is recalculated from
this by lengthy fourier transform. This is not "real-time", thus the convenience of our fast imaging is not available in such a system. This latter point is true for most non-nulling types of ellipsometers.

The disadvantage of the nulling concept is that the "measurement" of a precise ellipsometric value on one spot takes longer, because nulling requires a more complex movement of some optical components.

How large is the laser spot of the EP4?

Imaging ellipsometry, in contrast to scanning ellipsometry, is based on analyzing ellipsometric contrast micrographs at different positions of the optical components to obtain a delta and psi – map. This procedure is the reason for the unique lateral resolution of imaging ellipsometer and the short measurement time in comparison to scanning methods. The laser spot has to illuminate the complete field of view. In case of 2x objective a beam expander is needed to fulfill this requirement.

What is the number of bits for the CCD camera you use in the instrument?

The camera is digitized with 8 bits. However, sometimes less is more. The bit depth does not not limit the measurement process, nor the linearity, but it has a positive effect on the data transfer. Please note that the measurement is not "photometric" in our system in the sense that we do not use the camera signal directly. It is important to stress this because competitors use 14bit cameras in a completely different ellipsometric measurement procedure. Therefore, their data quality is not higher than ours, regardless of the camera bit depth. If you want to compare – please have a look at the results – you are invited to send us a sample for a contest!

Is it possible to enter data into the materials database?

Yes, the database may be upgraded very easily if n and k data and dispersion function, resepectivly are available. Also the results of optical modeling can be saved as a new material. 

What is the lateral resolution of the system?

Accurion FAQ objectivesThe lateral resolution depends on the used objective and wavelength. With a lower wavelength a higher resolution may be achieved.

!The lateral resolution is limited by the NA (numerical aperture) of the objectives and by the used wavelength. It can not be increased by using a camera with more pixels!

Can I increase the lateral resolution by using another camera?

The lateral resolution is limited by the NA (numerical aperture) of the objectives and by the used wavelength (see above table). It can not be increased by using a camera with more pixels. The standard camera in the system has more pixels than needed.

Can I use the EP4 together with a trough?

Accurion ep3bamYes. For all standard KSV troughs and NIMA troughs adaptions are available including a software adaption – trough variables like trough area and surface pressure will be automatically saved in EP3 images and measurements.

For other troughs an adaption is possible on request.
Please read also What accessories do I need to measure at liquid-air-interface? for further information about using troughs.

What laser do I need for measuring at liquid-air-interface?

With an EP4SW and EP4SE 50mW laser is needed (either green(532nm) or red(658nm). if used for liquid-air-interface. For EP4BAM systems 20mW is sufficient because of some missing optics. But if you plan to upgrade the EP4BAM to a full Ellipsometer EP4SW or EP4SE later, you should consider a 50mW laser.

What accessories do I need to measure at liquid-air-interface?

a) Active vibration isolation, Cabinet: The most important thing is to avoid vibrations or air circulations. For this purpose we offer active vibration elements that fit to EP4 platform. Also a Laser safety cabinet is available to avoid air circulations.

b) Z-Lift: A Z-Lift at the goniometer will allow an easy adaption of a trough. Because of evaporation the water level will sink continously, so the Z-level needs to be adjusted. Without a Z-Lift you would have to adjust the hight of your trough and level it which will cause vibration and could destroy the domains or monolayer

c) BAM-Tools: Some special software tools that make experiments at liquid-air-interface easier:
- Automatic z-leveler: Due to evaporation the level of the water will sind. When a Z-Lift is present at the system this tool will automatically detect a change of water level and lower the Goniometer.

- Special Background compensation: In all images you will also see the laser sopt and some interferences (see Point 1) as a background of your images. Those may be removed by this tool. The clue: It works also on water surfaces with moving domains.

- Thickness measurement: With this tool it is possible to calculate the thickness from the camera signal, also vs. Time. This is useful for EP4BAM, because here no ellipsometry is available to measure thicknesses. It can also be used for quicker kinetics or to calculate the thickness from taken images.

When can I use a 50X objective?

A 50X objective can’t be used for BAM applications because of the small working distance. With a 50x objective the highest possible AOI on a trough is 50°, but 54° is required.
Also with the SE option 50x can’t be used because of the low intensity. 50x objective can only be used with a laser or a special broadband filter.

Which objective should I use?

Accurion FAQ laser
For selection of the appropriate objective you should consider following facts:

- If you measure on homogenous samples or samples with structures larger than around 400µm you should use an objective with a large field of view.

- To make small structures (<4µm) visible the use of a high magnification objective (20X, 50X) together with a lower wavelength is recommended.

- The intensity of the reflected light depends on the objective.

So the 50X objective can’t be used for liquid-air-interfac or with the lamp because of the low reflected intensity. Also a 2X objective shouldn’t be used with a laser without “Beam Expander”! A Beam Expander enlarges the laser spot size from ~0.7mm to ~1.2cm.

Can I use a 20X objective on a liquid-air-interface?

Generally yes, but keep in mind that all the movement of your film on water as well as all vibrations will be magnified. So to achieve a higher resolution your film should be rigid and you must have a good vibration isolation (preferably active vibration isolation)

Can I use the EP4 without objective?

Yes. But in this case You won’t be able to do imaging. Anyway to gain more signal (e.g. when doing spectroscopic ellipsometry on water) it may be useful.

Can I measure at higher angles of incidence than 60°?

Yes. And you should sometimes, because the measurements are most sensitive when you measure close to brewster angle of the substrate (e.g. ~70° for Si).

To avoid the objective touching the sample or the stage you should place the sample on the most right side of the stage and move the stage to left. So you will ensure that the objective will move around the sample and won’t touch it.

What is the difference between one-zone-nulling and four-zone-nulling?

Accurion FAQSince the polarizer, compensator and analyzer can be rotated in a range of 360°, not only one nulling condition is possible but all together four nulling conditions at different angles of polarizer and analyzer and compensator=+/-45°.

With a one-zone-nulling only the first zone is measured. It is four times faster than 4-zone-nulling and is sufficient for relative measurements like binding kinetics. But by doing 4-zone-nulling all optical errors as well as anisotropie of the sample will be corrected by measuring at 4-zones and taking the average. This method leed to highest accuracy and is recommended for all absolute measurements.

How long does a spectroscopic measurement take?

A spectroscopic measurement with all available wavelengths and four-zone-measurement (to get highest accuracy) takes about 45 minutes. But there are several possibilities to save time. For example if the spectrum doesn’t have any peeks or minima (needs to be simulated by the model software before), you may use only every second or third wavelength. Also if there is a peek but the rest of the spectrum is “boring” you may select only the wavelength region around the peek, becuase it contains the most information.

Can I measure at solid-liquid-interface?

Yes. For this purpose we offer special fluidic cells: solid-liquid-cell for nontransparent substrates and kinetics-SPR-cell for transparent substrates as well as for SPR measurement. For both cells also a peltier temperature control and electrochemistry upgrade are available. Also a liquid handling system is available to automize binding kinetics for up to 6 different solutions.

How is it possible to use one quarter wave plate as compensator for all wavelengths?

The quarter wave plate used in ep3_se is an achromatic one. Nevertheless the retardation is not exactely 0.25 (quarter wavelength) for all wavelengths, but since the retardation is exactely known for each wavelength it will be automatically corrected by the software.

Can I do spectroscopic ellipsometry on liquid-air-interface?

Generally yes. But since the reflectivity of a liquid is normally very low, a special set of broadband filters are required for the spectroscopic box to allow higher intensity.Also a 2X objective is needed o collect more light.

What slides and prism and wavelength is recommended for SPR?

SPR-slides and prism must be selected according to the wavelength of light. Different types of SPR-slides are available either for use with green light (532 nm) or with red light (appr. 635 nm). SPR-slides for green light require a special 65° cut prism. SPR-slides for red light require the standard 60° cut prism. If the customer is interested in EP3 SW, a red laser at 658 nm with 60° prism is recommended. Alternatively a green laser with 65° prism is available. If the customer is interested in EP3 SE, the choice of laser is not important, since he shall use the red light from the lamp with 60° prism.

Since the SPR slides are made of SF10 also the prisms must be SF10 in any case.


Will active vibration isolation improve my results?

It really depends on your equipment, the environmental conditions and the aim of your work. If you have the impression that vibrations are disturbing your system, give us a call and ask for a site evaluation. In most cases we will find a solution for your setup.

Where do vibrations originate?

Vibrations in a laboratory or production building are often generated by running machinery like pumps and motors. In addition, HVAC equipment and the traffic passing nearby can be a source of vibrations. Last but not least wind and seismic activity can affect the building structure at low frequencies.

What is passive vibration isolation?

Passive vibration isolation is based on the mechanical low pass characteristic of a spring-mass-damper setup. A passive isolator reduces the ambient vibration for frequencies above its resonance. Within the resonance the vibrations get amplified!
For this reason passive isolation systems require a big mass, e.g. a heavy granite block, and soft springs with good damping, e.g. air springs, in order to achieve a low resonance frequency (typically 2 to 5 Hz). The amplification within the resonance and the long settling time after impacts are the drawback of passive isolators.

Why is Halcyonics’ active vibration isolation superior to a passive system?

Active vibration isolation measures and counteracts the vibration in a closed loop feedback system. Therefore, a resonance at the systems Eigenfrequency is eliminated, keeping your equipment well isolated even at low frequencies above 0.6 Hz.

May I test a Halcyonics isolator at my lab with my equipment?

The most reliable test, is the test under real conditions. Please contact us if you are interested in a demo. 

Are there limits to Accurion’s active vibration isolation?

Yes, there are technical limits.
a) Limits for heavy loads and/or high vibration amplitudes:
the electromagnetic actuators used in the active isolation system provide a limited force and stroke. For heavy loads and/or high vibration amplitudes it might happen that force or stroke of the actuators is not big enough to compensate the vibration
b) Limits for very small amplitudes:
the sensors used in the active system provide a limited sensitivity. Especially for low frequencies the sensitivity decreases rapidly. In a very calm environment it might happen that the vibration level is below the sensitivity of the sensor. In this case there will be no isolation.

To mount my delicate Laser optics I need a tapped surface like with an optical breadboard.

The Halcyonics_Micro and Workstation Series come with a flat top surface. As an option we offer tapped top plates with ¼”-20 threads on 1” centres or alternately M6 on 25 mm centres. In addition, customer specific drill and tap patterns are possible.

Do the Halcyonics units isolate against airborne noise?

Accurion’s Halcyonics department has developed acoustic enclosures to prevent sound and air currents from interference with sensitive instruments. These covers may be used with the active vibration isolation units or as stand-alone systems.

Which other accessories are available from Accurion?

Accessories to the active vibration isolation systems include rigid support frames, the acoustic covers and a vibration analysis tool named the “Explorer”. Other Accessories may be manufactured to match our customers’ needs.

How long is the service interval?

There is no service interval. After the 48-hours endurance test the systems are calibrated and sealed to run 24 hours a day, 365 days a year. By design there are no serviceable parts on the active vibration isolation systems except the fuses which protect the electronics from excess voltage surges.

Why is the old-fashioned voice-coil actuator used?

Halcyonics choose to go this way to avoid actuators based on piezoelectric elements. Although these components allow for precise and rapid positioning in many fields of technology, the naturally small amplitudes necessitate high driving voltages. Besides possible interference with the sensitive instruments atop an active vibration isolation system, the high electric potential in the range of several hundred Volts will increase efforts in safety related design changes and tests for CE conformity (a kind of safety regulation for the consumer in the EC). In addition, a resonance is observed with piezo actuators as it is with pneumatic systems, although at different frequencies and amplitudes.
The R&D department of Halcyonics was able to develop an improved electromagnetic actuator that is equipped with a magnet made of a Neodymium based material rather than a Ferritic. The former shows a much stronger magnetic field in relation to mass and size, so that the complete actuator unit could be made much smaller and less heavy than its predecessor and still working at a convenient voltage of only 24 VDC.

What is the origin of the name 'Halcyonics'?

When the company Halcyonics was founded in 1997, one of the partners suggested the name. Its origins go back to the Greek mythological figure Alcyone, one of the Plejades and daughter of Aeolus, the god of winds.

She was married to Ceyx, king of Thessaly, who went one day on a voyage on a ship. Since he and his wife had angered Zeus, the god killed Ceyx by sending a thunderstorm, drowning Alcyones husband.

When she learned about the fate of her companion, she threw herself from the cliff into the sea to join Ceyx in death. The gods had pity with the couple and turned the lovers into Halcyon birds, which have their names from the same Alcyone character.

When the couple, now as birds, returned back to shore, Alcyones father Aeolus calmed the seas to allow them to build a nest in safety. In the eastern part of the Mediterranean Sea the time around the end of the year, when the wind has calmed and the sea is flat, is still named the "Halcyon days." This term has found its way into general language, describing a calm and peaceful time in general.

Halcyonics active vibration isolation systems provide the scientists of the modern days with a calm surface, independent of the time of the year, without sacrificing themselves or a family member.

For more information about the Greek mythology character of Alcyone, see:

and on the Halcyon birds, the Kingfisher:

© Accurion GmbH 2021