Axial intensity distribution of converging spherical wave behind an elliptic aperture

2011 ◽  
Author(s):  
M. Miler ◽  
T. Martan
Keyword(s):  
Intensity Distribution ◽  
Spherical Wave ◽  
Converging Spherical Wave ◽  
Elliptic Aperture

scholarly journals Randomly Multiplexed Diffractive Lens and Axicon for Spatial and Spectral Imaging

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 437 ◽  
Author(s):  
Vijayakumar Anand ◽  
Tomas Katkus ◽  
Saulius Juodkazis
Keyword(s):  
Intensity Distribution ◽  
Point Spread Function ◽  
Fresnel Zone ◽  
Spherical Wave ◽  
Optical Element ◽  
Intensity Pattern ◽  
Object Space ◽  
Point Spread ◽  
Spread Function ◽  
Complicated Object

A new hybrid diffractive optical element (HDOE) was designed by randomly multiplexing an axicon and a Fresnel zone lens. The HDOE generates two mutually coherent waves, namely a conical wave and a spherical wave, for every on-axis point object in the object space. The resulting self-interference intensity distribution is recorded as the point spread function. A library of point spread functions are recorded in terms of the different locations and wavelengths of the on-axis point objects in the object space. A complicated object illuminated by a spatially incoherent multi-wavelength source generated an intensity pattern that was the sum of the shifted and scaled point spread intensity distributions corresponding to every spatially incoherent point and wavelength in the complicated object. The four-dimensional image of the object was reconstructed using computer processing of the object intensity distribution and the point spread function library.

Phase-Shifting Method with Unknown Intervals in Phase-Shifting Digital Holography

2006 ◽  
Vol 3-4 ◽  
pp. 211-216
Author(s):  
T. Kita ◽  
Yoshiharu Morimoto ◽  
Motoharu Fujigaki ◽  
Toru Matui
Keyword(s):  
Phase Shift ◽  
Intensity Distribution ◽  
Digital Holography ◽  
Phase Distribution ◽  
Reference Beam ◽  
Spherical Wave ◽  
High Accuracy ◽  
Displacement Measurement ◽  
Phase Shifting ◽  
Phase Shifting Method

Displacement measurement can be performed with high accuracy using phase-shifting method. In phase-shifting method, it is often used four steps of phase-shifting for one cycle. In conventional method, to measure the displacement of an object by an interferometer, the phase of a reference beam should be shifted by every π/2 in the four-step phase-shifting. In this paper, a phase-shifting method with unknown intervals is proposed. This method does not need to shift a phase by every π/2. It can detect an intensity distribution and a phase distribution from five fringe images with equal intervals even if the phase-shift amount is unknown. Using this method, we propose a displacement measurement of phase-shifting digital holographic interferometry using spherical wave as reference wave.

Structure images of Si, Ge and Mos2 crystals and some application to radiation damage studies

1978 ◽  
Vol 36 (1) ◽  
pp. 292-293 ◽  
Author(s):  
K. Izui ◽  
T. Nishida ◽  
S. Furuno ◽  
H. Otsu ◽  
S. Kuwabara
Keyword(s):  
Radiation Damage ◽  
Exposure Time ◽  
Gaussian Distribution ◽  
Intensity Distribution ◽  
Chromatic Aberration ◽  
Magnetic Lens

Recently we have observed the structure images of silicon in the (110), (111) and (100) projection respectively, and then examined the optimum defocus and thickness ranges for the formation of such images on the basis of calculations of image contrasts using the n-slice theory. The present paper reports the effects of a chromatic aberration and a slight misorientation on the images, and also presents some applications of structure images of Si, Ge and MoS2 to the radiation damage studies.(1) Effect of a chromatic aberration and slight misorientation: There is an inevitable fluctuation in the amount of defocus due to a chromatic aberration originating from the fluctuations both in the energies of electrons and in the magnetic lens current. The actual image is a results of superposition of those fluctuated images during the exposure time. Assuming the Gaussian distribution for defocus, Δf around the optimum defocus value Δf0, the intensity distribution, I(x,y) in the image formed by this fluctuation is given by

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