ZEISS has developed the light sheet microscope that permits the three-dimensional observation of biological samples over very long periods of time. The MEMS scanner developed by the Fraunhofer Institute for Photonic Microsystems IPMS is used in this microscope.

The light sheet fluorescence microscope system Lightsheet Z.1 (Figure above) for the first time gives researchers the opportunity to observe dynamic processes in large living organisms. Compared to former methods of fluorescence microscopy such as confocal microscopy, this system is characterized by a much lower light load on the specimens, opening up whole new possibilities for gentle, long-term examinations of living organisms in 3D. Light sheet fluorescence microscopy (LSFM) allows only the relevant volume and not the entire specimen to be illuminated for a section of the fluorescence-marked tissue by a very thin, expanded laser beam, the so-called light sheet. This means that the fluorescent dye is only locally excited to emit light. A projection lens that points vertically on the light sheet with a downstream camera efficiently records the emitted light. For the first time, specimens can now be recorded under natural, physiological conditions and the development of entire organisms tracked three-dimensionally for many days.

A resonant microscanner developed by the Fraunhofer IPMS is used to perfect the imaging quality and eliminate unwanted artefacts such as shadowing caused by opaque components of the specimen in the light sheet. The pivot scanner (or MEMS scanner) has a reflecting plate with a diameter of 1.2 mm and a mechanical scanning amplitude that can be dynamically adapted to the desired lens magnification in the range from 0.9 - 6°, and will be operated near its mechanical resonance at 23 kHz. The angle of the light sheet changes relative to the specimen within the illumination plane depending on the position of the reflecting plate, and accordingly the direction of the shadow. Thanks to the high scanning frequency of the MEMS scanner, no additional averaging effort is needed, the camera is integrated automatically through its exposure time. Compared to conventional resonant galvanometer scanners, the MEMS scanner from the Fraunhofer IPMS convinces through not only its small size but also a much more stable oscillation mode and an absolute freedom from noise. The scanning module and the control electronics are adapted to the requirements of the microscopy system starting from the modular LDC (Laser Deflection Cube) platform of the Fraunhofer IPMS.

About Carl Zeiss Microscopy
The Microscopy business group at ZEISS is the world's only manufacturer of light, X-ray and electron microscopes. The company's extensive portfolio enables research and routine applications in the life and materials sciences. The product range includes light and laser scanning microscopes, X-ray microscopes, electron and ion microscopes and spectrometer modules. Users are supported for software for system control, image capture and editing. The Microscopy business group has sales companies in 33 countries. Application and service specialists support customers around the globe in demo centers and on site. The business group is headquartered in Jena, Germany. Additional production and development sites are in Oberkochen, Göttingen and Munich, as well as in Cambridge in the UK and Peabody, MA and Pleasanton, CA in the USA. The company has around 2,800 employees and generates revenue of 650 million euros.

Contact
Dr. Jochen Tham, ZEISS, Microscopy
Phone +49 3641 64-3949
E-Mail: jochen.tham@zeiss.com

About Fraunhofer IPMS
The Fraunhofer Institute for Photonic Microsystems IPMS and its 220 employees turn over an annual research volume of 22 million euros. Fraunhofer IPMS generates more than two thirds of this production capacity out of commissions from industry and publicly financed projects in applied research. The focus of our development and production services lies in the practical industrial application of unique technological know-how in the fields of (optical) micro-electromechanical systems [MEMS, MOEMS]. Fraunhofer IMPS uses scientific know-how, application experience and customer contacts as well as modern equipment and clean room infrastructure. Fraunhofer IPMS covers a broad spectrum of industrial applications. Our services range from initial conception to product development, right down to serial pilot production – from a single component to a complete system solution.