Analysis of the pinhole array illumination source for high precision wavefront error metrology

2015 ◽  
Author(s):  
Zengxiong Lu ◽  
Yuejing Qi ◽  
Qingbin Meng ◽  
Jiani Su ◽  
Guangyi Liu
Keyword(s):  
High Precision ◽  
Wavefront Error ◽  
Array Illumination ◽  
Illumination Source

Optimized Analysis of Random Point Array Illumination Source for Nanometer Accuracy Wavefront Error Testing

2015 ◽  
Vol 35 (6) ◽  
pp. 0612007
Author(s):  
卢增雄 Lu Zengxiong ◽  
齐月静 Qi Yuejing ◽  
齐威 Qi Wei ◽  
苏佳妮 Su Jiani ◽  
彭卓君 Peng Zhuojun
Keyword(s):  
Random Point ◽  
Wavefront Error ◽  
Error Testing ◽  
Array Illumination ◽  
Illumination Source

Confocal position alignment in high-precision wavefront error metrology using Shack-Hartmann wavefront sensor

2016 ◽  
Author(s):  
Jiani Su ◽  
Zengxiong Lu ◽  
Yuejing Qi ◽  
Guangyi Liu ◽  
Qingbin Meng
Keyword(s):  
High Precision ◽  
Wavefront Sensor ◽  
Wavefront Error

Fabrication of Computer Generated Hologram for Aspheric Surface Measurement

2016 ◽  
Vol 1136 ◽  
pp. 620-623
Author(s):  
Zhi Yu Zhang ◽  
Xu Yang ◽  
Li Gong Zheng
Keyword(s):  
Line Width ◽  
High Precision ◽  
Glass Substrate ◽  
Semiconductor Industry ◽  
Position Error ◽  
Surface Measurement ◽  
High Precision Measurement ◽  
Aspheric Surfaces ◽  
Wavy Line ◽  
Wavefront Error

High-precision aspheric surfaces are generally measured using interferometer with a computer-generated holograms (CGH), which has a wavy line pattern fabricated onto a glass substrate. CGH patterns are generally made using lithographic techniques that was developed for semiconductor industry. Patterns can be subsequently etched into glass substrate using reactive ion or chemical etching. The accuracy of the drawn pattern on a CGH decides the accuracy of the measurement. Draw pattern error mainly includes the line-width deviation and its position error. In this paper, the influences of defocus of drawing laser and the wet-etching processes on the line-width were firstly investigated. On the other hand, the position error under different line-width was obtained by analyzing the relationship of line-width error and the position error. Based on the above-obtained results, a CGH having a diameter of 80 mm and the minimum line-width of 1.8 μm was successfully fabricated. Testing results showed that the wavefront error was only 3.79 nm, significantly higher than the commercial-available ones. The fabricated CGH is expected to use in the high-precision measurement of asphercal surfaces.

scholarly journals High precision wavefront control in point spread function engineering for single emitter localization

2018 ◽  
Author(s):  
M. Siemons ◽  
C. N. Hulleman ◽  
R. Ø. Thorsen ◽  
C. S. Smith ◽  
S. Stallinga
Keyword(s):  
High Precision ◽  
Point Spread Function ◽  
Time Window ◽  
Wavefront Aberration ◽  
Wavefront Control ◽  
Point Spread ◽  
Spread Function ◽  
Wavefront Error ◽  
Single Emitter ◽  
Emitter Localization

AbstractPoint spread function (PSF) engineering is used in single emitter localization to measure the emitter position in 3D and possibly other parameters such as the emission color or dipole orientation as well. Advanced PSF models such as spline fits to experimental PSFs or the vectorial PSF model can be used in the corresponding localization algorithms in order to model the intricate spot shape and deformations correctly. The complexity of the optical architecture and fit model makes PSF engineering approaches particularly sensitive to optical aberrations. Here, we present a calibration and alignment protocol for fluorescence microscopes equipped with a spatial light modulator (SLM) with the goal of establishing a wavefront error well below the diffraction limit for optimum application of complex engineered PSFs. We achieve high-precision wavefront control, to a level below 20 mλ wavefront aberration over a 30 minute time window after the calibration procedure, using a separate light path for calibrating the pixel-to-pixel variations of the SLM, and alignment of the SLM with respect to the optical axis and Fourier plane within 3 µm (x/y) and 100 µm (z) error. Aberrations are retrieved from a fit of the vectorial PSF model to a bead z-stack and compensated with a residual wavefront error comparable to the error of the SLM calibration step. This well-calibrated and corrected setup makes it possible to create complex ‘3D+λ’ PSFs that fit very well to the vectorial PSF model. Proof-of-principle bead experiments show precisions below 10 nm in x, y, and λ, and below 20 nm in z over an axial range of 1 µm with 2000 signal photons and 12 background photons.

Automatic measurement of SAED patterns from asbestos minerals

1988 ◽  
Vol 46 ◽  
pp. 846-847
Author(s):  
J. C. Russ ◽  
T. Taguchi ◽  
P. M. Peters ◽  
E. Chatfield ◽  
J. C. Russ ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
High Precision ◽  
Diffraction Data ◽  
Automatic Measurement ◽  
Automatic Method ◽  
Important Method ◽  
X Ray ◽  
Integrated Intensity ◽  
Asbestiform Minerals ◽  
True Center

Conventional SAD patterns as obtained in the TEM present difficulties for identification of materials such as asbestiform minerals, although diffraction data is considered to be an important method for making this purpose. The preferred orientation of the fibers and the spotty patterns that are obtained do not readily lend themselves to measurement of the integrated intensity values for each d-spacing, and even the d-spacings may be hard to determine precisely because the true center location for the broken rings requires estimation. We have implemented an automatic method for diffraction pattern measurement to overcome these problems. It automatically locates the center of patterns with high precision, measures the radius of each ring of spots in the pattern, and integrates the density of spots in that ring. The resulting spectrum of intensity vs. radius is then used just as a conventional X-ray diffractometer scan would be, to locate peaks and produce a list of d,I values suitable for search/match comparison to known or expected phases.

On effects of non-systematic reflections on weak-beam images of partial dislocations

1991 ◽  
Vol 49 ◽  
pp. 688-689
Author(s):  
K. Z. Botros ◽  
S. S. Sheinin
Keyword(s):  
High Precision ◽  
Stacking Fault ◽  
Important Application ◽  
Stacking Fault Energy ◽  
Sharp Peak ◽  
Weak Beam ◽  
Partial Dislocations ◽  
Deviation Parameter ◽  
Beam Diffraction

The main features of weak beam images of dislocations were first described by Cockayne et al. using calculations of intensity profiles based on the kinematical and two beam dynamical theories. The feature of weak beam images which is of particular interest in this investigation is that intensity profiles exhibit a sharp peak located at a position very close to the position of the dislocation in the crystal. This property of weak beam images of dislocations has an important application in the determination of stacking fault energy of crystals. This can easily be done since the separation of the partial dislocations bounding a stacking fault ribbon can be measured with high precision, assuming of course that the weak beam relationship between the positions of the image and the dislocation is valid. In order to carry out measurements such as these in practice the specimen must be tilted to "good" weak beam diffraction conditions, which implies utilizing high values of the deviation parameter Sg.

Digital differential hysteresis iimage processing displays what the microscope acquires but the eye can't see

1995 ◽  
Vol 53 ◽  
pp. 642-643
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
Image Processing ◽  
Visual System ◽  
High Precision ◽  
Image Data ◽  
Processing Technology ◽  
Output Data ◽  
Contrast Resolution ◽  
Pixel Intensity ◽  
Data Reading ◽  
Hysteresis Properties

Differential hysteresis processing is a new image processing technology that provides a tool for the display of image data information at any level of differential contrast resolution. This includes the maximum contrast resolution of the acquisition system which may be 1,000-times higher than that of the visual system (16 bit versus 6 bit). All microscopes acquire high precision contrasts at a level of <0.01-25% of the acquisition range in 16-bit - 8-bit data, but these contrasts are mostly invisible or only partially visible even in conventionally enhanced images. The processing principle of the differential hysteresis tool is based on hysteresis properties of intensity variations within an image.Differential hysteresis image processing moves a cursor of selected intensity range (hysteresis range) along lines through the image data reading each successive pixel intensity. The midpoint of the cursor provides the output data. If the intensity value of the following pixel falls outside of the actual cursor endpoint values, then the cursor follows the data either with its top or with its bottom, but if the pixels' intensity value falls within the cursor range, then the cursor maintains its intensity value.

High precision measurement of the SOS surface thickness in the rough phase

1991 ◽  
Vol 1 (12) ◽  
pp. 1669-1673 ◽  
Author(s):  
Hans Gerd Evertz ◽  
Martin Hasenbusch ◽  
Mihail Marcu ◽  
Klaus Pinn ◽  
Sorin Solomon
Keyword(s):  
High Precision ◽  
Precision Measurement ◽  
High Precision Measurement ◽  
Surface Thickness
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