Peer-Reviewed Papers
Quantitative and Direct Near-field Analysis of Plasmonic-Induced Transparency and the Observation of a Plasmonic Breathing Mode
W. Khunsin, J. Dorfmüller, M. Eßlinger, R. Vogelgesang, C. Rockstuhl, C. Etrich, and K. Kern
ACS Nano, 10, 2, 2214-2224 (2016)
doi: 10.1021/acsnano.5b06768
show abstract
We investigated experimentally and numerically in the optical near-field a plasmonic model system similar to dolmen-type structure for phenomena like plasmon-induced transparency. Through engineering of coupling strength, structure orientation, and incident angle and phase of the excitation source it was possible to control near-field excitation of the dark modes. We showed that quantitative analysis of near-field amplitude and excitation strength provided essential information that allowed identifying the interaction between the bright and the dark mode and how it causes the formation of plasmon-induced transparency features and a Fano resonance. In addition, we introduced a mechanism to excite field distributions in plasmonic structures that cannot be accessed directly using far-field illumination and demonstrate the excitation of a dark mode akin to a symmetry-forbidden plasmonic breathing mode using a linearly polarized far-field source.
Phase Engineering of Subwavelength Unidirectional Plasmon Launchers
M. Eßlinger, W. Khunsin, J. Dorfmüller, N. Talebi, R. Vogelgesang, and K. Kern
Adv. Opt. Mat., 1, 6, 434-437 (2013)
doi: 10.1002/adom.201300135
show abstract
Ultrasmall couplers for the excitation of plasmonic structures by photonic modes are presented. They are constructed by assembling point-like resonators in the near-field zone of the target structure. As a demonstration of its efficacy, this scheme is applied to unidirectional excitation of plasmonic waveguides. The overall footprint of the resulting coupling structures is less than λ²/10.
Plasmonic Oligomers in Cylindrical Vector Light Beams
M. Hentschel, J. Dorfmüller, H. Giessen, S. Jäger, A. M. Kern, K. Braun, D. Zhang, and A. J. Meixner
Beilstein J. Nanotechnol., 4, 57-65 (2013)
doi: 10.3762/bjnano.4.6
show abstract
We investigate the excitation as well as propagation of magnetic modes in plasmonic nanostructures. Such structures are particularly suited for excitation with cylindrical vector beams. We study magneto-inductive coupling between adjacent nanostructures. We utilize high-resolution lithographic techniques for the preparation of complex nanostructures consisting of gold as well as aluminium. These structures are subsequently characterized by linear optical spectroscopy. The well characterized and designed structures are afterwards studied in depth by exciting them with radial and azimuthally polarized light and simultaneously measuring their plasmonic near-field behavior. Additionally, we attempt to model and simulate our results, a project which has, to the best of our knowledge, not been attempted so far.
Background-Free Imaging of Plasmonic Structures with Cross-Polarized Apertureless Scanning Near-Field Optical Microscopy
M. Eßlinger, J. Dorfmüller, W. Khunsin, R. Vogelgesang, and K. Kern
Rev. Sci. Instrum., 83, 3, 033704 (2012)
doi: 10.1063/1.3693346
show abstract
We present advances in experimental techniques of apertureless scanning near-field optical microscopy (aSNOM). The rational alignment procedure we outline is based upon a phase singularity that occurs while scanning polarizers around the nominal cross-polarized configuration of s-polarized excitation and p-polarized detection. We discuss the theoretical origin of this topological feature of the setup, which is robust against small deviations, such as minor tip misalignment or shape variations. Setting the polarizers to this singular configuration point eliminates all background signal, allowing for reproducible plasmonic eigenmode mapping with optimal signal-to-noise ratio.
Plasmonic antennas, positioning, and coupling of individual quantum systems
D. Drégely, K. Lindfors, J. Dorfmüller, M. Hentschel, M. Becker, J. Wrachtrup, M. Lippitz, R. Vogelgesang, and H. Giessen
Phys. Status Solidi B, 249, 4, pp. 666-677 (2012)
doi: 10.1002/pssb.201100781
on the cover of "physica status solidi b"
show abstract
Plasmonic nanoantennas can enhance the radiative decay rate of quantum emitters via the Purcell-effect. Similar to their radiofrequency equivalents, they can also direct the emitted light into preferential directions. In this paper we first investigate plasmonic Yagi-Uda antennas that are able to confine light to and direct light from subwavelength size volumes. Hence, enhanced transition rates and directed emission are expected when near-field coupling between quantum emitters and the antennas is achieved. Second, we present suitable techniques to couple different quantum systems to plasmonic antennas. We use top-down fabrication techniques to achieve positioning of individual quantum emitters relative to plasmonic nanostructures with an accuracy better than 10 nm. We assure a sufficiently small distance for an efficient near-field coupling of the transition dipole to the plasmonic nanoantenna, which is, however, large enough not to quench the transition. The hybrid system using quantum dots, molecules, or nitrogen-vacancy (NV)-centers in diamond can serve as an efficient single photon source. It is suitable for high-speed information transfer at optical frequencies on the nanoscale for future applications.
Spectral Shifts in Optical Nanoantenna Enhanced Hydrogen Sensor
A. Tittl, C. Kremers, J. Dorfmüller, D. N. Chigrin, and H. Giessen
Opt. Mater. Express 2, 2, pp. 111-118 (2012)
doi: 10.1364/OME.2.000111
show abstract
In this work, we numerically investigate the nature of spectral shifts in antenna-enhanced hydrogen sensing geometries consisting of a gold bowtie antenna next to a palladium nanodisk. We find through extensive finite element (FEM) simulations that the hydrogen-induced spectral behavior of the system is governed by two competing effects: a small blueshift caused by dielectric function changes in the palladium and a much stronger redshift due to an expansion of the palladium lattice. Our findings enable the accurate numerical characterization and especially the optimization of sensitive antenna-enhanced hydrogen sensors. As a first application, we calculate the performance improvement of gap antennas compared to single cut-wire antenna elements.
Magnetic plasmon formation and propagation in artificial aromatic molecules
N. Liu, S. Mukherjee, K. Bao, L. V. Brown, J. Dorfmüller, P. Nordlander, and N. J. Halas
Nano Lett. 12, 1, pp. 364-369 (2012)
doi: 10.1021/nl203641z
show abstract
The plasmonic properties of coupled metallic nanostructures are understood through the analogy between their collective plasmon modes and the electronic orbitals of corresponding molecules. Here we expand this analogy to planar arrangements of plasmonic nanostructures whose magnetic plasmons directly resemble the delocalized orbitals of aromatic hydrocarbon molecules. The heptamer structure serves as a benzene-like building block for a family of plasmonic artificial aromatic analogs with fused ring structures. Antiphase magnetic plasmons are excited in adjacent fused heptamer units, which for a linear multiheptamer structure is a behavior controlled by the number of units in the structure. This antiphase coupling gives rise to plasmonic “antiferromagnetic” behavior in multiple repeated heptamer structures, supporting the propagation of low-loss magnetic plasmons in this new waveguide geometry.
Long-distance Indirect Excitation of Nanoplasmonic Resonances
W. Khunsin, B. Brian, J. Dorfmüller, M. Eßlinger, R. Vogelgesang, C. Etrich, C. Rockstuhl, A. Dmitriev, and K. Kern
Nano Lett. 11, 7, pp. 2765-2769 (2011)
doi: 10.1021/nl201043v
show abstract
In nanoscopic systems, size, geometry, and arrangement are the crucial determinants of the light-matter interaction and resulting nanoparticles excitation. At optical frequencies, one of the most prominent examples is the excitation of localized surface plasmon polaritons, where the electromagnetic radiation is coupled to the confined charge density oscillations. Here, we show that beyond direct near- and far-field excitation, a long-range, indirect mode of particle excitation is available in nanoplasmonic systems. In particular, in amorphous arrays of plasmonic nanodiscs we find strong collective and coherent influence on each particle from its entire active neighborhood. This dependency of the local field response on excitation conditions at distant areas brings exciting possibilities to engineer enhanced electromagnetic fields through controlled, spatially configured illumination.
Near-field Dynamics of Optical Yagi-Uda Nanoantennas
J. Dorfmüller, D. Drégely, M. Eßlinger, W. Khunsin, R. Vogelgesang, K. Kern, and H. Giessen
Nano Lett. 11, 7, pp. 2819-2824 (2011)
doi: 10.1021/nl201184n
show abstract
We present near-field measurements of optical Yagi-Uda nanoantennas that are used in receiving mode. The eigenmode imaging of amplitude and phase by apertureless scanning near-field optical microscopy allows us to investigate the dynamics of the local out-of-plane electric field components and to visualize the temporal evolution of this time-harmonic reception process. The antenna directionality manifests itself by the dependence of the local field enhancement at the feed element on the illumination direction. Simulations taking into account the substrate confirm our observation of the directionality. Our work demonstrates the possibility to characterize multielement nanoantennas by electromagnetic antenna near-field scanners.
3D optical Yagi-Uda nanoantenna-array
D. Drégely, R. Taubert, J. Dorfmüller, R. Vogelgesang, K. Kern, and H. Giessen
Nat. Commun. 2, 267 (2011)
doi: 10.1038/ncomms1268
show abstract
Future photonic circuits with the capability of high-speed data processing at optical frequencies will rely on the implementation of efficient emitters and detectors on the nanoscale. Towards this goal, bridging the size mismatch between optical radiation and subwavelength emitters or detectors by optical nanoantennas is a subject of current research in the field of plasmonics. Here we introduce an array of three-dimensional optical Yagi-Uda antennas, fabricated using top-down fabrication techniques combined with layer-by-layer processing. We show that the concepts of radiofrequency antenna arrays can be applied to the optical regime proving superior directional properties compared with a single planar optical antenna, particularly for emission and reception into the third dimension. Measuring the optical properties of the structure reveals that impinging light on the array is efficiently absorbed on the subwavelength scale because of the high directivity. Moreover, we show in simulations that combining the array with suitable feeding circuits gives rise to the prospect of beam steering at optical wavelengths.
Surface plasmon coupling to nanoscale Schottky-type electrical detectors
T. Dufaux, J. Dorfmüller, R. Vogelgesang, M. Burghard, and K. Kern
Appl. Phys. Lett. 97, 16, 161110 (2010)
doi: 10.1063/1.3503534
show abstract
We have investigated the near-field coupling of surface plasmons to a titanium/CdS nanowire interface for two different device configurations. A bare aluminum grating on an underlying aluminum layer exhibited the expected stronger electrical signal for perpendicular versus parallel light polarization. An opposite intensity ratio was detected when the grating and the Schottky contact are connected via an aluminum-silica-aluminum sandwich structure. Based upon finite difference time domain device simulations, the enhanced coupling for parallel polarization is attributed to the emergence of a transversal electric wave within the metal-insulator-metal structure.
Plasmonic Nanowire Antennas: Experiment, Simulation, and Theory
J. Dorfmüller, R. Vogelgesang, W. Khunsin, C. Rockstuhl, C. Etrich, and K. Kern
Nano Lett. 10, 9, pp. 3596-3603 (2010)
doi: 10.1021/nl101921y
show abstract
Recent advances in nanolithography have allowed shifting of the resonance frequency of antennas into the optical and visible wavelength range with potential applications, for example, in single molecule spectroscopy by fluorescence and directionality enhancement of molecules. Despite such great promise, the analytical means to describe the properties of optical antennas is still lacking. As the phase velocity of currents at optical frequencies in metals is much below the speed of light, standard radio frequency (RF) antenna theory does not apply directly. For the fundamental linear wire antenna, we present an analytical description that overcomes this shortage and reveals profound differences between RF and plasmonic antennas. It is fully supported by apertureless scanning near-field optical microscope measurements and finite-difference time-domain simulations. This theory is a starting point for the development of analytical models of more complex antenna structures.
Large scale simulations in the realm of nanooptics
C. Rockstuhl, C. Etrich, C. Helgert, C. Menzel, T. Paul, S. Fahr, T. Pertsch, J. Dorfmüller, R. Esteban, W. Khunsin, R. Vogelgesang, K. Kern, A. Dmitriev, K. Bittkau, T. Beckers, R. Carius, and F. Lederer
Proc. SPIE 7604, 76040D (2010)
doi: 10.1117/12.841700
show abstract
The realm of nanooptics is usually characterized by the interaction of light with structures having relevant feature sizes much smaller than the wavelength. To model such problems, a large variety of methods exists. However, most of them either require a periodic arrangement of a unit cell or can handle only single entities. But there exists a great variety of functional devices which may have either a spatial extent much larger than the wavelength and which comprise structural details with sizes in the order of a fraction of the wavelength or they may consist of an amorphous arrangement of strongly scattering entities. Such structures require large scale simulations where the fine details are retained. In this contribution we outline our latest research on such devices and detail the computational peculiarities we have to overcome. Presenting several examples, we show how simulations support the physical understanding of these devices. Examples are randomly textured surfaces used for solar cells, where guided modes excited in the light absorbing layers strongly affect the solar cell efficiency, amorphous metamaterials and stochastically arranged nanoantennas. The usage of computational experiments will be motivated by the unprecedented insight into the functionality of such components.
Plasmonic Activity of Large-Area Gold Nanodot Arrays on Arbitrary Substrates
M. Mäder, T. Höche, J. W. Gerlach, S. Perlt, J. Dorfmüller, M. Saliba, R. Vogelgesang, K. Kern, and B. Rauschenbach
Nano Lett. 10, 1, pp. 47-51 (2010)
doi: 10.1021/nl903633z
show abstract
Highly efficient fabrication of well-ordered, embedded gold nanodot matrices using diffraction mask projection laser ablation is demonstrated. These gold nanodot arrays are ideally generated onto sapphire substrates but do also form onto AlOx thin films, enabling the application to arbitrary bulk substrates. Well-ordered gold dots become embedded into the Al2O3 substrate during the process, thus improving their mechanical stability, chemical inertness, and technological compliance. Such substrates may be useful, for example, to enhance solar-cell efficiency by surface plasmons or as convenient, biocompatible focusing elements in nearfield optical tweezers.
Fabry-Pérot Resonances in One-Dimensional Plasmonic Nanostructures
J. Dorfmüller, R. Vogelgesang, R. T. Weitz, C. Rockstuhl, C. Etrich, T. Pertsch, F. Lederer, and K. Kern
Nano Lett. 9, 6, pp. 2372-2377 (2009)
doi: 10.1021/nl900900r
show abstract
We study the near-field optical behavior of Fabry-Pérot resonances in thin metal nanowires, also referred to as quasi one-dimensional plasmonic nanoantennas. From eigenmodes well beyond quadrupolar order we extract both, propagation constant and reflection phase of the guided surface plasmon polariton with superb accuracy. The combined symmetry breaking effects of oblique illumination and retardation allow the excitation of dipole forbidden, even order resonances. All measurements are supported by rigorous simulations of the experimental situation.
Direct Near-Field Optical Imaging of Higher Order Plasmonic Resonances
R. Esteban, R. Vogelgesang, J. Dorfmüller, A. Dmitriev, C. Rockstuhl, C. Etrich, and K. Kern
Nano Lett. 8, 10, pp. 3155-3159 (2008)
doi: 10.1021/nl801396r
show abstract
We map in real space and by purely optical means near-field optical information of localized surface plasmon polariton (LSPP) resonances excited in nanoscopic particles. We demonstrate that careful polarization control enables apertureless scanning near-field optical microscopy (aSNOM) to image dipolar and quadrupolar LSPPs of the bare sample with high fidelity in both amplitude and phase. This establishes a routine method for in situ optical microscopy of plasmonic and other resonant structures under ambient conditions.
Plasmonic nanostructures in aperture-less scanning near-field optical microscopy (aSNOM)
R. Vogelgesang, J. Dorfmüller, R. Esteban, R. T. Weitz, A. Dmitriev, and K. Kern
Phys. Status Solidi B 245, 10, pp. 2255-2260 (2008)
doi: 10.1002/pssb.200879617
show abstract
Apertureless scanning near-field optical microscopy offers superb spatial resolution, but interpreting the recoreded signal can still be a challenge. Especially images of eigenmodes in plasmonic nanostructures are very often obscured by concurrent scattering from the tip and/or coupling effects in hte tip sample system. We show here how the use of orthogonal polarizations in excitation and detection affords us with an elegant method to map near-fields of plasmonic eignenmodes and other optical phenomenta. We demonstrated with a variety of samples possible applications of this cross-polarization scheme, such as verification of functional nanooptical structures, systematic studies of localized and propagating plasmonic eignenmodes, and their susceptibility to disturbance from structural defects.
Amplitude- and phase-resolved optical near fields of split-ring-resonator-based metamaterials
T. Zentgraf, J. Dorfmüller, C. Rockstuhl, C. Etrich, R. Vogelgesang, K. Kern, T. Pertsch, F. Lederer, and H. Giessen
Opt. Lett. 33, 8, pp. 848-850 (2008)
doi: 10.1364/OL.33.000848
show abstract
We investigate the local optical response of split-ring resonator-(SRR)-based metamaterials with an apertureless scanning near-field optical microscope. By mapping the near fields of suitably resonant micrometersized SRRs in the near-infrared spectral region with an uncoated silicon tip, we obtain a spatial resolution of better than λ/50. The experimental results confirm numerical predictions of the near-field excitations of SRRs. Combining experimental near-field optical studies with near- and far-field optical simulations provides a detailed understanding of resonance mechanisms in subwavelength structures and will facilitate an efficient approach to improved designs.
Electronic-Band-Structure Mapping of Nanotube Transistors by Scanning Photocurrent Microscopy
E. J. H. Lee, K. Balasubramanian, J. Dorfmüller, R. Vogelgesang, N. Fu, A. Mews, M. Burghard, and K. Kern
Small 3, 12, pp. 2038-2042 (2007)
doi: 10.1002/smll.200700418
show abstract
Carbon-nanotube field-effect transistors are characterised using scanning photocurrent microscopy. The photocurrent response (see image), reflecting the strength of the local built-in electric field, depends on the applied source-drain bias and the charge-transport regime adjusted by the back-gate voltage. Such measurements enable the extraction of electronic band-structure profiles corresponding to the different operation conditions.
Book Chapters
Fabrication, characterization and applications of optical antenna arrays
D. Drégely, J. Dorfmüller, M. Hentschel, and H. Giessen
in: Optical Antennas, edited by M. Agio and A. Alú, Cambridge University Press (2013)
ISBN: 978-1-107-01414-5
Theses
Optical Wire Antennas: Near-Field Imaging, Modeling and Emission Patterns
J. Dorfmüller
PhD thesis, EPF Lausanne (2010)
Link to Open-Access-Server
show abstract
In this thesis we study the properties of optical wire antennas. As experimental method for our investigations we use apertureless near-field optical microscopy. This technique achieves high spatial resolution well beyond the diffraction limit by utilizing the field enhancement at the apex of sharp tips. An interferometric measurement scheme allows us to detect both near-field intensity and optical phase. By using s-polarized light for illumination and detecting the p-polarized component of the backscattered light we are able to map the z-component of the electrical near-field. Optimizing polarizer and analyzer angles of our cross-polarization scheme ensures a background free plasmonic eigenmode mapping. By comparison with simulation data not including the tip we show that the measurement has little to no influence on the eigenmode.
The samples investigated in this thesis are arrays of gold nano-wires prepared by electron beam lithography. We observe plasmon resonances in our near-field images as patterns of lobes and explain them by regarding the wires as one dimensional Fabry-Pérot resonators. The number of nodes in between the lobes is the resonance order. From eigenmodes well beyond quadrupolar order we extract both, propagation constant and reflection phase of the guided surface plasmon polariton with superb accuracy. The combined symmetry breaking effects of oblique illumination and retardation allow the excitation of dipole forbidden even-order resonances. By systematically varying the azimuthal illumination angle we are able to map the directional receiving and emission patterns of the wire antennas.
In order to understand these patterns we develop an analytical model. In contrast to radio frequency (RF) antenna theories we not only assume surface currents but also take volume currents into account. The model also allows us to spotlight the differences between plasmonic and RF antennas. The equations we derive describe both, the property of the wires as resonators as well as the antenna emission / reception patterns. With just four — physically motivated — parameters we are able to fit measured as well as simulated data astonishingly well. With this model predicting the relative intensity and phase of the light absorbed and scattered by nano-wire antennas it has great potential for future research.
Implementation of an Apertureless Scanning Near-Field Optical Microscope for the Infrared Spectrum
J. Dorfmüller
Diploma Thesis, Universität Konstanz (2006)
Link to Open-Access-Server
show abstract
In this thesis, a new apertureless scanning near-field optical microscope (aSNOM) with the ability to resolve optical properties of surfaces with a lateral resolution better than 50 nm in a broadband infrared (IR) spectrum is described.
The high resolution beyond the diffraction limit is achieved by using the sharp tip of an atomic force microscope (AFM) to probe the local electromagnetic field of a sample situated at nanometer distance. A continuous wave (cw) laser beam is focused onto the apex of a metalized or dielectric AFM tip with an apex radius of about 10 nm. The backscattered light is mixed with a reference beam of the same wavelength and detected with a nitrogen cooled InSb-photovoltaic diode. This interferometric scheme allows to enhance the signal level and to detect both the amplitude and phase of the scattered light. The obtained signal is influenced by two components: the light scattered in a small vicinity of the tip apex containing near-field information from the sample, and a background field scattered from the body of the tip and from the sample. To suppress the background component, the AFM is used in non-contact mode with a small vibration amplitude, and the signal is demodulated at higher harmonics of the tip vibration frequency with a lock-in amplifier. By raster scanning the sample under the AFM tip, near-field information from the sample is obtained simultaneously with the topography.
Imaging in a broad infrared spectrum is achieved by using a cw optical parametric oscillator (cw-OPO) as light source. The OPO has been carefully characterized and gives the instrument the capability to image in a spectral region from 1.5 to 3.8 μm with a small gap between 2.0 and 2.3 μm. By using spherical mirrors instead of lenses, the setup is nearly achromatic.
As applications of the infrared aSNOM (IR-aSNOM), images of two different sub-wavelength gold structures on glass surfaces were taken. The first is a test sample that shows the capability of the instrument to image material contrast with a lateral resolution better than 50 nm, corresponding to λ/50. The second application shown is the investigation of split-ring resonators, which are of interest for the study of negative index materials. Maps of optical near-fields at the resonantly excited plasmonic structures are shown — with similar resolution.
Radar Meteorology with a 54.1 MHz Boundary Layer Radar
J. Dorfmüller
Semester Project, University of Adelaide (2002)
Link
show abstract
The principles of radar meteorology are shown. A radar set measures distances and velocities of objects using radio waves. By measuring the diffraction pattern of clear air backscattering it is possible to measure the wind velocities in all three directions. Different Atmospheric phenomena have different signal patterns. These patterns are correlated to surface data and data from soundings. The signal of a cold front and a high pressure region are examined in more detail in this report. A cold front shows a weakening in the signal strength and a change in the wind direction. At the front of a cold front an upward motion of the air is observed, in the cold front a strong downward movement. A high pressure region shows a large pattern scale of the diffraction pattern.
Patents
Verfahren zur Positionierung eines bildaufnehmenden Elements zu optischen Einrichtung und Verwendung des Verfahrens
J. Dorfmüller, R. Dootz; Robert Bosch GmbH
Date of registration: 09.10.2014; Link: DE 10 2014 220 519 A1
show abstract
Die Erfindung betrifft ein Verfahren zur Positionierung eines bildaufnehmenden Elements zu einer optischen Einrichtung, bei dem ein Referenzbild über die optische Einrichtung als Bild auf dem bildaufnehmenden Element erzeugt wird, wobei an mehreren Stellen des bildaufnehmenden Elements Daten des Bildes bezüglich eines Kriteriums mittels einer Auswerteeinrichtung ausgewertet werden, wobei in einem ersten Durchgang die Position der optischen Einrichtung oder des bildaufnehmenden Elements relativ zu dem bildaufnehmenden Element oder der optischen Einrichtung von einer ersten Position in eine zweite Position verstellt wird, wobei während der Verstellung zwischen der ersten in die zweite Position Daten des Bilds an den mehreren Stellen des bildaufnehmenden Elements erfasst und der Auswerteeinrichtung zugeführt werden, wobei in der Auswerteeinrichtung Grenzwerte für das Kriterium bezüglich jeder Stelle des Bilds abgespeichert sind, wobei anschließend die optische Einrichtung oder das bildaufnehmende Element bei Nichterreichen der Grenzwerte an den Stellen in eine gegenüber der ersten Stellung veränderte erste Position zur Durchführung wenigstens eines weiteren Durchgangs positioniert wird, wobei die veränderte erste Position aufgrund der Daten des Bildes bei dem zuletzt gemachten Durchgangs bestimmt wird, und wobei eine derartige Anzahl von Durchgängen durchgeführt wird, bis sich die Daten des Bildes zumindest im Wesentlichen nicht mehr ändern.
Verfahren und Vorrichtung zum Positionieren einer optischen Einrichtung zu einem bildaufnehmenden Element
S. Rindle, M. Maier, M. Henke, U. Apel, M. Reinhold, G. Franz, R. Dootz, J. Dorfmüller, P. Preller; Robert Bosch GmbH
Date of registration: 27.10.2014; Link: DE 10 2014 221 757 A1
show abstract
Die Erfindung betrifft ein Verfahren zum Positionieren einer optischen Einrichtung zu einem bildaufnehmenden Element oder umgekehrt, wobei ein elektromagnetisches Referenzsignal durch die optische Einrichtung auf das bildaufnehmende Element abgestrahlt wird, und wobei das von der optischen Einrichtung empfangene Signal des Referenzsignals zumindest mittelbar ausgewertet wird, um daraus die Position zwischen der optischen Einrichtung und dem bildaufnehmenden Element zu bestimmen, und mit Mitteln zum Verstellen der optischen Einrichtung relativ zum bildaufnehmenden Element oder umgekehrt. Erfindungsgemäß ist es vorgesehen, dass die optische Einrichtung das Referenzsignal zumindest teilweise reflektiert und das reflektierte Signal nach Durchgang durch die optische Einrichtung erfasst und ausgewertet wird.
Vorrichtung für ein optisches Sensorelement, optisches Sensorelement und Herstellungsverfahren zum Herstellen einer Vorrichtung für ein optisches Sensorelement
N. Bauer, S. Rindle, M. Maier, J. Dorfmüller, U. Apel, M. Reinhold, G. Franz; Robert Bosch GmbH
Date of registration: 11.12.2014; Link: DE 10 2014 225 509 A1
show abstract
Die Erfindung betrifft eine Vorrichtung für ein optisches Sensorelement. Die Vorrichtung umfasst ein Objektiv, wobei das Objektiv zumindest einen konvex ausgeformten Außenwandabschnitt einer Außenwand des Objektivs aufweist, und eine Hülse für eine bewegliche Lagerung des Objektivs, wobei die Hülse zumindest einen konkav ausgeformten Innenwandabschnitt einer Innenwand der Hülse aufweist, wobei der konkav ausgeformte Innenwandabschnitt der Hülse ausgebildet sind, um den konvex ausgeformten Außenwandabschnitt des Objektivs aufzunehmen.
Fertigung von Kameras mit verminderter Ausschussquote
J. Dorfmüller; Robert Bosch GmbH
Anmeldetag: 10.03.2020; Offenlegungsschrift DE 10 2021 202 312 A1
Zusammenfassung anzeigen
Verfahren zur Fertigung einer Kamera mit den Schritten:
•es werden vorgefertigte Bauteile (2a, 2b) bereitgestellt;
mindestens zwei dieser vorgefertigten Bauteile (2a, 2b) werden zueinander nach Maßgabe mindestens eines vorgegebenen Optimalitätskriteriums justiert;
•diese Bauteile (2a, 2b) werden im justierten Zustand miteinander verklebt, wobei zusätzlich;
•Vorab-Daten (4a, 4b), die ein konkretes Exemplar (2a1-2a5, 2b1- 2b5) mindestens eines der vorgefertigten Bauteile (2a, 2b) charakterisieren, und/oder Messdaten in Bezug auf die optische Leistung der Kombination der zueinander justierten Bauteile (2a, 2b), von einem trainierten Machine Learning-Modell auf eine Prognose für die optische Leistung abgebildet werden, die die Kamera liefern wird, nachdem sie nach dem Verkleben mindestens einen weiteren Fertigungsschritt durchlaufen hat; und
•diese Prognose als Feedback für eine Einwirkung auf den Fertigungsprozess herangezogen wird.
BibTeX
