An small unmanned aerial vehicle (UAV) circles above the ground, capturing the typical green of a coniferous forest or the radiated heat from a town. The objectives in its on-board measuring equipment must function free of chromatic aberration across a wide spectral range – from the ultraviolet region through the visible band and right up to the near and medium infrared range.
In such a scenario, conventional lens systems comprised of several lens elements are of limited use: when required to image a wide spectral range, the image quality drops – the image suffers from color fringing and becomes blurred. Traditionally, specific lenses have been used for each different spectral band. However, the difficulty is that UAVs can only carry a limited amount of weight.
Researchers from the Fraunhofer Institute for Photonic Microsystems IPMS are currently working to make it possible to capture images free from chromatic aberration in a number of spectral ranges using a single system. This would have the advantage of prolonging the battery’s life and increasing the aircraft’s endurance. Group manager Dr. Heinrich Grüger of the IPMS says: “We’ve come up with a design for a new objective in which we’ve used mirrors instead of standard lens elements.” The objective is comprised of four mirrors, carefully arranged to avoid obscuration – this produces a higher-contrast image. Two deformable mirrors take care of the triple zoom range – with no loss of image quality. The new design eliminates the need for elaborate mechanical guides within the lens barrel.
Grüger believes the new objective is potentially highly marketable: “Both the automation technology sector and the automobile and equipment engineering sector would profit from this type of objective.” Suitable deformable mirrors will have to be created – conventional optical mirrors are rigid. Grüger says: “For the zoom function, we need mirrors that will permit flexible actuator control of the radius of curvature.”
Although IPMS scientists have already developed deformable mirrors, they have not yet managed to achieve the size and degree of variability required for the mirror zoom objective. Optical simulations have shown that the mirrors would need to be at least 12 millimeters in diameter in order to produce a zoom objective with a sufficient f-number. Nevertheless, the researchers have already been able to demonstrate the optical performance of the objective: they built three identical setups with three different focal lengths in which the deformable mirrors were replaced by conventional rigid mirrors.
Kristof Seidl | Fraunhofer Gesellschaft
Hope to discover sure signs of life on Mars? New research says look for the element vanadium
22.09.2017 | University of Kansas
22.09.2017 | Forschungszentrum MATHEON ECMath
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy