scholarly journals An online diagnosis technique for simultaneous measurement of the fundamental, second and third harmonics in one snapshot

2019 ◽  
Vol 7 ◽  
Author(s):  
Xue Dong ◽  
Xingchen Pan ◽  
Cheng Liu ◽  
Jianqiang Zhu
Keyword(s):  
Random Phase ◽  
High Accuracy ◽  
Measurement Methods ◽  
Laser Beams ◽  
Phase Plate ◽  
Diffraction Intensity ◽  
Compact Structure ◽  
Laser Driver ◽  
Diffraction Patterns ◽  
Diagnosis Technique

A three-wavelength coherent-modulation-imaging (CMI) technique is proposed to simultaneously measure the fundamental, second and third harmonics of a laser driver in one snapshot. Laser beams at three wavelengths (1053 nm, 526.5 nm and 351 nm) were simultaneously incident on a random phase plate to generate hybrid diffraction patterns, and a modified CMI algorithm was adopted to reconstruct the complex amplitude of each wavelength from one diffraction intensity frame. The validity of this proposed technique was verified using both numerical simulation and experimental analyses. Compared to commonly used measurement methods, this proposed method has several advantages, including a compact structure, convenient operation and high accuracy.

scholarly journals High-Accuracy Surface Topography Manufacturing for Continuous Phase Plates Using an Atmospheric Pressure Plasma Jet

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 683
Author(s):  
Huiliang Jin ◽  
Caixue Tang ◽  
Haibo Li ◽  
Yuanhang Zhang ◽  
Yaguo Li
Keyword(s):  
Surface Topography ◽  
Atmospheric Pressure ◽  
High Efficiency ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jet ◽  
Continuous Phase ◽  
High Accuracy ◽  
Phase Plate ◽  
Atmospheric Pressure Plasma Jet ◽  
Pressure Plasma

The continuous phase plate (CPP) is the vital diffractive optical element involved in laser beam shaping and smoothing in high-power laser systems. The high gradients, small spatial periods, and complex features make it difficult to achieve high accuracy when manufacturing such systems. A high-accuracy and high-efficiency surface topography manufacturing method for CPP is presented in this paper. The atmospheric pressure plasma jet (APPJ) system is presented and the removal characteristics are studied to obtain the optimal processing parameters. An optimized iterative algorithm based on the dwell point matrix and a fast Fourier transform (FFT) is proposed to improve the accuracy and efficiency in the dwell time calculation process. A 120 mm × 120 mm CPP surface topography with a 1326.2 nm peak-to-valley (PV) value is fabricated with four iteration steps after approximately 1.6 h of plasma processing. The residual figure error between the prescribed surface topography and plasma-processed surface topography is 28.08 nm root mean square (RMS). The far-field distribution characteristic of the plasma-fabricated surface is analyzed, for which the energy radius deviation is 11 μm at 90% encircled energy. The experimental results demonstrates the potential of the APPJ approach for the manufacturing of complex surface topographies.

scholarly journals Beam-smoothing effect in broad-band random-phase irradiation

1993 ◽  
Vol 11 (2) ◽  
pp. 385-390 ◽  
Author(s):  
I. Matsushima ◽  
Y. Owadano ◽  
Y. Matsumoto ◽  
I. Okuda ◽  
T. Tomie ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Optical System ◽  
Random Phase ◽  
Broad Band ◽  
Laser Fusion ◽  
Phase Plate ◽  
Smoothing Effect ◽  
Broad Bandwidth ◽  
A New Technique ◽  
Focusing Lens

A new technique to achieve smooth laser irradiation profiles on laser fusion targets is evaluated numerically and experimentally. In this technique, smoothing is obtained by using a spectral dispersing optic and a random-phase plate placed in front of a focusing lens employing the broad-bandwidth of KrF lasers. Experimental results and numerical calculations agree well, verifying that this simple optical system is effective for smooth irradiation on targets.

Kinematical two-dimensional multiple-diffraction intensity profiles. Application to ω–ψ scans of silicon and diamond obtained with synchrotron radiation

2001 ◽  
Vol 34 (2) ◽  
pp. 157-165 ◽  
Author(s):  
E. Rossmanith ◽  
A Hupe ◽  
R. Kurtz ◽  
H. Schmidt ◽  
H.-G. Krane
Keyword(s):  
Synchrotron Radiation ◽  
Incident Beam ◽  
Mosaic Structure ◽  
Two Dimensional ◽  
Diffraction Intensity ◽  
Multiple Diffraction ◽  
Crystal Sample ◽  
Diffraction Patterns ◽  
Kinematical Theory

In a previous paper by Rossmanith [J. Appl. Cryst.(2000),33, 1405–1414], expressions for the calculation of multiple-diffraction patterns observed in ω–ψ scans of Bragg reflections were derived within the framework of the kinematical theory, taking into account the divergence and wavelength spread of the incident beam, as well as the mosaic structure of the crystal sample. Agreement with CuKα experiments was demonstrated. In this paper, it is shown that the theoretical expressions are also suitable for synchrotron radiation experiments.

Laser wander effect in turbulence simulation system with random phase plate

2011 ◽  
Vol 23 (8) ◽  
pp. 2044-2036
Author(s):  
甘新基 Gan Xinji ◽  
郭劲 Guo Jin ◽  
徐抒岩 Xu Shuyan
Keyword(s):  
Random Phase ◽  
Simulation System ◽  
Phase Plate ◽  
Turbulence Simulation

scholarly journals Development of the Correction Algorithm to Limit the Deformation of Bacterial Colonies Diffraction Patterns Caused by Misalignment and Its Impact on the Bacteria Identification in the Proposed Optical Biosensor

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5797
Author(s):  
Igor Buzalewicz ◽  
Agnieszka Suchwałko ◽  
Magdalena Karwańska ◽  
Alina Wieliczko ◽  
Halina Podbielska
Keyword(s):  
Optical Biosensor ◽  
High Accuracy ◽  
Identification Accuracy ◽  
Optical Biosensors ◽  
Bacterial Colony ◽  
Factors Affecting ◽  
Bacteria Identification ◽  
Spatial Intensity Distribution ◽  
Diffraction Patterns ◽  
The Impact

Recently proposed methods of bacteria identification in optical biosensors based on the phenomenon of light diffraction on macro-colonies offer over 98% classification accuracy. However, such high accuracy relies on the comparable and repeatable spatial intensity distribution of diffraction patterns. Therefore, it is essential to eliminate all non-species/strain-dependent factors affecting the diffraction patterns. In this study, the impact of the bacterial colony and illuminating beam misalignment on the variation of classification features extracted from diffraction patterns was examined. It was demonstrated that misalignment introduced by the scanning module significantly affected diffraction patterns and extracted classification features used for bacteria identification. Therefore, it is a crucial system-dependent factor limiting the identification accuracy. The acceptable misalignment level, when the accuracy and quality of the classification features are not affected, was determined as no greater than 50 µm. Obtained results led to development of image-processing algorithms for determination of the direction of misalignment and concurrent alignment of the bacterial colonies’ diffraction patterns. The proposed algorithms enable the rigorous monitoring and controlling of the measurement’s conditions in order to preserve the high accuracy of bacteria identification.

Design and analysis of a novel random phase plate for uniform illumination

1998 ◽  
Author(s):  
Zengshui Liu ◽  
Runwen Wang ◽  
Huijie Huang ◽  
Dunwu Lu
Keyword(s):  
Random Phase ◽  
Phase Plate ◽  
Uniform Illumination

Broadband Random Phase Diffuser for Ultrasonic Imaging

1979 ◽  
Vol 1 (4) ◽  
pp. 325-332
Author(s):  
Gerard A. Alphonse ◽  
David Vilkomerso
Keyword(s):  
Solid Angle ◽  
Random Phase ◽  
Ultrasonic Imaging ◽  
Standing Waves ◽  
Acoustic Imaging ◽  
Point Sources ◽  
Phase Plate ◽  
Reflected Waves ◽  
Large Aperture ◽  
The Waves

In reflective imaging, waves must be scattered by the object over a broad solid angle so that some of the reflected waves impinge upon the collecting aperture. Surfaces such as biological specimens under study in acoustic imaging are considered smooth at the wavelengths used (e.g., 1 mm) and therefore act as specular reflectors. In order to obtain reflection over a broad spatial range, large aperture, sector or compound scanning are used. In certain types of systems, diffuse insonification is sometimes used by imaging a raster of random phase points onto the surface. However interference between the waves from these point sources produces random fringes or “speckle-like” patterns overlaying the image. In optics these fringes have been reduced by rotating the diffuser. A similar approach has been taken here. This paper describes a simple random phase plate having two levels, 0° and 180 phase that can, by rotation, change the relative phases of the diffuse insonification points so as to reduce the speckle-like effect in the image. The temporal bandwidth of the random phase plate is narrow because of standing waves in it. To reduce standing waves the diffuser is intimately coupled to a wedged transducer. This combination is used to obtain diffuse insonification with broad spatial and temporal bandwidth.

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