Aperture-coded confocal profilometry. - In: Optics letters, ISSN 1539-4794, Bd. 41 (2016), 23, S. 5523-5526
This letter introduces a novel principle to the confocal profilometry for simultaneous measurement of surface position and tilt. The principle relies on an angle-dependent coding of the illumination of the surface-under-test, achieved by dividing the pupil into several subapertures. The reflected light is decoded to perform an angle-resolved analysis by measuring the intensity contributions of each individual subaperture. By comparing their contributions, additional information of surface tilt can be inferred. For our demonstration experiment the subapertures are encoded with specific spectral distribution, which may be called wavelength division encoding. Alternate coding procedures such as temporal or code division encoding are also feasible.
https://doi.org/10.1364/OL.41.005523
Efficient quantization of tunable helix phase plates. - In: Optics letters, ISSN 1539-4794, Bd. 41 (2016), 20, S. 4755-4758
Helix phase plates are used in a variety of applications from optical trapping to astronomy. Tunable helix phase plates based on the AlvarezLohmann principle allow variation of the topological charge of the helix by rotating the phase plates with respect to each other around the optical axis. Current designs generate an undesired inverse phase in the section determined by the rotation angle. We present tunable phase plates that use a special quantization to maintain a uniform phase over the tuning range, suppressing the undesired part. As one benefit, the efficiency of the elements is increased over the whole tuning range.
https://doi.org/10.1364/OL.41.004755
An imaging spectrometer employing tunable hyperchromatic microlenses. - In: Light, ISSN 2047-7538, Bd. 5 (2016), (8. Apr.), e16058, insges. 9 S.
Richtiger Name des 3. Verfassers: Patrick Feßer
http://dx.doi.org/10.1038/lsa.2016.58
Fast and scalable algorithm for the simulation of multiple Mie scattering in optical systems. - In: Applied optics, ISSN 2155-3165, Bd. 55 (2016), 15, S. 3887-3896
The Monte Carlo simulation of light propagation in optical systems requires the processing of a large number of photons to achieve a satisfactory statistical accuracy. Based on classical Mie scattering, we experimentally show that the independence of photons propagating through a turbid medium imposes a postulate for a concurrent and scalable programming paradigm of general purpose graphics processing units. This ensures that, without rewriting code, increasingly complex optical systems can be simulated if more processors are available in the future.
https://doi.org/10.1364/AO.55.003887
Simple unimorph deformable mirrors fabricated from piezo buzzers. - In: Journal of micromechanics and microengineering, ISSN 1361-6439, Bd. 26 (2016), 5, 055009, S. 1-t7
https://doi.org/10.1088/0960-1317/26/5/055009
Kollineare Modellierung komplexer optischer Systeme. - In: Photonik, ISSN 1432-9778, Bd. 48 (2016), 2, S. 46-49
Beim Entwurf komplexer zweifach optisch abbildender Systeme ist eine erste Dimensionierung auf der Grundlage der kollinearen Abbildungsgleichungen notwendig. Mit dem neu überarbeiteten Windows-Programm PARAX steht ein Softwaretool zur kollinearen Optikdimensionierung in der Entwurfphase optisch abbildender Systeme zur Verfügung.
Aluminum nitride and diamond membranes for tunable micro-optics. - In: Tunable micro-optics, (2016), S. 219-240
Adaptive scanning micro-eye. - In: Tunable micro-optics, (2016), S. 369-394
Ultrathin Alvarez lens system actuated by artificial muscles. - In: Applied optics, ISSN 2155-3165, Bd. 55 (2016), 10, S. 2718-2723
A key feature of Alvarez lenses is that they may be tuned in focal length using lateral rather than axial translation, thus reducing the overall length of a focus-tunable optical system. Nevertheless the bulk of classical microsystems actuators limits further miniaturization. We present here a new, ultrathin focus-tunable Alvarez lens fabricated using molding techniques and actuated using liquid crystal elastomer (LCE) artificial muscle actuators. The large deformation generated by the LCE actuators permits the integration of the actuators in-plane with the mechanical and optical system and thus reduces the device thickness to only 1.6 mm. Movement of the Alvarez lens pair of 178 [my]m results in a focal length change of 3.3 mm, based on an initial focal length of 28.4 mm. This design is of considerable interest for realization of ultraflat focus-tunable and zoom systems.
https://doi.org/10.1364/AO.55.002718
Subaperture stitching for measurement of freeform wavefront. - In: Applied optics, ISSN 2155-3165, Bd. 54 (2015), 34, S. 10022-10028
A method based on subaperture stitching for measurement of a freeform wavefront is proposed and applied to wavefronts calculated from the slope data acquired using a scanning Shack Hartmann sensor (SHS). The entire wavefront is divided into a number of subapertures with overlapping zones. Each subaperture is measured using the SHS, which is scanned over the entire wavefront. The slope values and thus the phase values of separately measured subapertures cannot be connected directly due to various misalignment errors during the scanning process. The errors lying in the vertical plane, i.e., piston, tilt, and power, are minimized by fitting them in the overlapping zone. The radial and rotational misalignment errors are minimized during registration in the global frame by using active numerical alignment before the stitching process. A mathematical model for a stitching algorithm is developed. Simulation studies are presented based on the mathematical model. The proposed mathematical model is experimentally verified on freeform surfaces of a cubic phase profile.
https://doi.org/10.1364/AO.54.010022