When telescopes look into space, they usually have only a limited view, even on star-bright nights – molecules in the atmosphere „block“ their view. Scientists at the Laser Zentrum Hannover e.V. (LZH) have developed and produced narrowband filters for the European Extremely Large Telescope (E-ELT), which block interfering signals.
In contrast to telescopes stationed in outer space, earth based telescopes inevitably measure interference signals in the atmosphere. In order to filter out this static, scientists at the LZH are developing special coatings for the optical components of the E-ELT. The work group Coatings has already developed first filters with a thickness of 60 to 100 µm on a substrate with a diameter of 100 mm. The narrowband filters block out interference and transmit signals into space in narrow bands in the infrared range (IR). The coating, made using ion beam sputtering, must have a homogeneity of 0.1% or less.
Filters make more exact measuring possible
Production of complex filters is a challenge, since a compromise between the coating thickness and the quality must always be found. Because of this, Dr. Stefan Günster, head of the Coatings Group, works closely with the astronomers of the Max Planck Institute for Extraterrestrial Physics and the University Observatory of the Ludwig-Maximilian-Universität München. The filter coating should improve the signal-to-noise ratio. This means the measurement time can be shortened, and thus more exact measurements are possible.
The scientists working with Dr. Günster use a special wideband filter monitor developed by the LZH, which covers a very wide wavelength range of 380 to 1700 nm. “With this instrument we can monitor the coating during production, and optimize it if necessary”, explains Stefan Günster. “Since coating the filter is very sophisticated, due to its thickness, we can save considerable development time doing so.”
Examining form accuracy
The relatively high physical thickness of the coatings places mechanical stress on the optics: the filters are deformed and influence the measurements. “We are presently working on processes, which can be used to monitor and control the form accuracy of the optics,” adds Dr. Günster.
As soon as the coating process has become established, the narrowband filters can also be used in other areas: for example for biological and medical applications that need high quality measurements in the IR range.
The Coating Group will be at the Optatec from May 20th to 22nd, 2014, in Hall 3, Stand H39.
Lena Bennefeld | Laser Zentrum Hannover e.V.
A blueprint for clearing the skies of space debris
17.04.2015 | RIKEN
Quantum Physics – Hot and Cold at the Same Time
17.04.2015 | Ruprecht-Karls-Universität Heidelberg
Astronomers from Chalmers University of Technology have used the giant telescope Alma to reveal an extremely powerful magnetic field very close to a supermassive black hole in a distant galaxy
Astronomers from Chalmers University of Technology have used the giant telescope Alma to reveal an extremely powerful magnetic field very close to a...
A team of physicists from MPQ, Caltech, and ICFO proposes the combination of nano-photonics with ultracold atoms for simulating quantum many-body systems and creating new states of matter.
Ultracold atoms in the so-called optical lattices, that are generated by crosswise superposition of laser beams, have been proven to be one of the most...
According to new research out of the Texas A&M Health Science Center College of Medicine, that is indeed the case. Chetan Jinadatha, M.D., M.P.H., assistant...
Researchers from ICFO, MIT and UC Riverside have been able to develop a graphene-based photodetector capable of converting absorbed light into an electrical voltage at ultrafast timescales
The efficient conversion of light into electricity plays a crucial role in many technologies, ranging from cameras to solar cells.
Electrical charges not only move through wires, they also travel along lengths of DNA, the molecule of life. The property is known as charge transport.
In a new study appearing in the journal Nature Chemistry, authors, Limin Xiang, Julio Palma, Christopher Bruot and others at Arizona State University's...
13.04.2015 | Event News
25.03.2015 | Event News
19.03.2015 | Event News
17.04.2015 | Power and Electrical Engineering
17.04.2015 | Earth Sciences
17.04.2015 | Physics and Astronomy