scholarly journals Incoherent light sources for speckle reduction in double pass ocular imaging

Author(s):  
Donatus Halpaap ◽  
Meritxell Vilaseca ◽  
Cristina Masoller
Author(s):  
Dietrich Bertram ◽  
Matthias Born ◽  
Thomas Jüstel

Author(s):  
Zacarías Malacara-Hernández

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Seungjae Lee ◽  
Dongyeon Kim ◽  
Seung-Woo Nam ◽  
Byounghyo Lee ◽  
Jaebum Cho ◽  
...  

Abstract Speckle reduction is an important topic in holographic displays as speckles not only reduce signal-to-noise ratio but also possess an eye-safety issue. Despite thorough exploration of speckle reduction methods using partially coherent light sources, the trade-off involved by the partial coherence has not been thoroughly discussed. Here, we introduce theoretical models that quantify the effects of partial coherence on the resolution and the speckle contrast. The theoretical models allow us to find an optimal light source that maximizes the speckle reduction while minimizing the decline of the other terms. We implement benchtop prototypes of partially coherent holographic displays using the optimal light source, and verify the theoretical models via simulation and experiment. We also present a criterion to evaluate the depth of field in partially coherent holographic displays. We conclude with a discussion about approximations and limitations inherent in the theoretical models.


1994 ◽  
Vol 342 ◽  
Author(s):  
R. Singh ◽  
J. Mavoori ◽  
R. P. S. Thakur ◽  
S. Narayanan

ABSTRACTThere are fundamental differences between conventional furnace processing (CFP) and rapid isothermal processing (RIP). The radiation spectrum of a conventional furnace consists of photons in the infrared and longer wavelength regions, whereas the spectrum of the incoherent light sources used in RIP consist of some ultraviolet, visible, and infrared photons. As compared to CFP, the photophysical and photochemical effects associated with RIP provide the capability of lower temperature processing. Due to photoeffects in RIP, differences are observed in junction movement and defect evolution with different lamp configurations and different kinds of lamps having differing spectra. This implies that diffusion models, in addition to considering processing time and temperature, should also account for the lamp configurations and spectra of the heating sources. The fundamental understanding of photoeffects in RIP can be further exploited to reduce the overall thermal budget used in the manufacturing of semiconductor devices. In this paper we present our study of photoeffects in RIP, which can be of help in the design of the next generation of RIP equipment.


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