Study on the alignment error of complex modulation for focusing flattop beam shaping

An alignment-free sensing module for the positioning system based on tunneling magnetoresistive (TMR) sensors with an absolute-incremental-integrated scale is demonstrated. The sensors of the proposed system for both lines consist of identical layer stacks; therefore, all sensors can be fabricated in identical processes from thin film deposition to device patterning on a single substrate. Consequently, the relative position of the sensors can be predefined at the lithography stage and the alignment error between sensors caused by the manual installation is completely eliminated. Different from the existing sensing scheme for incremental lines, we proposed to utilize the magnetic tunnel junctions with a perpendicular anisotropy reference layer and an in-plane anisotropy sensing layer. The sensors are placed parallel to the scale plane with magnetization of the sensing layer in the plane, which show the capability of polarity detection for the absolute line and reveal sinusoidal output signal for the incremental line. Furthermore, due to the large signal of TMR, the working distance can be further improved compared with conventional sensors. In addition, the cost of the positioning system is expected to be lowered, since all the sensors are fabricated in the same process without extra installation. Our design may pave a new avenue for the positioning system based on a magnetic detection scheme.

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Convolutional neural network as a tool for automatic alignment of electron optical beam shaping devices

Microscopy and Microanalysis ◽

10.1017/s143192762100324x ◽

2021 ◽

Vol 27 (S1) ◽

pp. 822-824

Author(s):

Enzo Rotunno ◽

Amir Tavabi ◽

Paolo Rosi ◽

Stefano Frabboni ◽

Peter Tiemeijer ◽

...

Keyword(s):

Neural Network ◽

Convolutional Neural Network ◽

Beam Shaping ◽

Optical Beam ◽

Automatic Alignment

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Holographic Display System to Suppress Speckle Noise Based on Beam Shaping

Photonics ◽

10.3390/photonics8060204 ◽

2021 ◽

Vol 8 (6) ◽

pp. 204

Author(s):

Di Wang ◽

Yi-Wei Zheng ◽

Nan-Nan Li ◽

Qiong-Hua Wang

Keyword(s):

Optical Element ◽

Speckle Noise ◽

Beam Shaping ◽

Diffractive Optical Element ◽

The Other ◽

Spatial Light Modulators ◽

Viewing Angle ◽

Display System ◽

Holographic Display ◽

Light Modulators

In this paper, a holographic system to suppress the speckle noise is proposed. Two spatial light modulators (SLMs) are used in the system, one of which is used for beam shaping, and the other is used for reproducing the image. By calculating the effective viewing angle of the reconstructed image, the effective hologram and the effective region of the SLM are calculated accordingly. Then, the size of the diffractive optical element (DOE) is calculated accordingly. The dynamic DOEs and effective hologram are loaded on the effective regions of the two SLMs, respectively, while the wasted areas of the two SLMs are performed with zero-padded operations. When the laser passes through the first SLM, the light can be modulated by the effective DOEs. When the modulated beam illuminates the second SLM which is loaded with the effective hologram, the image is reconstructed with better quality and lower speckle noise. Moreover, the calculation time of the hologram is reduced. Experiments indicate the validity of the proposed system.

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Anti-Reflection Nanostructures on Tempered Glass by Dynamic Beam Shaping

Micromachines ◽

10.3390/mi12030289 ◽

2021 ◽

Vol 12 (3) ◽

pp. 289

Author(s):

Petr Hauschwitz ◽

Jan Brajer ◽

Danijela Rostohar ◽

Jaromír Kopeček ◽

Tomáš Mocek ◽

...

Keyword(s):

Mobile Phones ◽

Thermal Damage ◽

Pulsed Laser ◽

Processing Parameters ◽

Beam Shaping ◽

Separation Distance ◽

Tempered Glass ◽

Fundamental Wavelength ◽

Speed Up ◽

Scanning Head

Reflectivity and surface topography of tempered glass were modified without any thermal damage to the surroundings by utilizing 1.7 ps ultrashort pulsed laser on its fundamental wavelength of 1030 nm. To speed up the fabrication, a dynamic beam shaping unit combined with a galvanometer scanning head was applied to divide the initial laser beam into a matrix of beamlets with adjustable beamlets number and separation distance. By tuning the laser and processing parameters, reflected intensity can be reduced up to 75% while maintaining 90% of transparency thus showing great potential for display functionalization of mobile phones or laptops.

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