Nonlinear recording effects on holographic re ection gratings recorded on BB640 emulsions have been studied. Using an analytical approach to the characteristic curve of this emulsions, the density profiles recorded in the developed emulsions that correspond to the original light pattern generated by the holographic setup have been obtained. The final spatial profiles of the refraction index resulting from different exposure levels and different bleaching processes have been evaluated studying the experimental diffraction efficiency and comparing it with Kogelnik's theory. The quality of the fittings of this model with the experimental spectral responses of the final gratings has been used as a measure of the accordance between the original sinusoidal and periodical light distribution and the obtained modulation profile of the processed hologram. The range of applicability of the theoretical model to the experimental results has been evaluated using different bleaching processes.
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http://dx.doi.org/10.1364/oe.11.001906 | DOI Listing |
Nano Lett
January 2025
Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
The complete manipulation of Jones matrix phase-channels using metasurfaces brings forth unparalleled possibilities across diverse wavefront modulation applications. Traditionally, achieving independent control over all four phase-channels usually involves the introduction of chirality with multilayer or three-dimensional metasurfaces. Here, we present a general chirality-free method that relies on polarization base transformation with a planar minimalist metasurface, effectively decoupling the four Jones matrix phase-channels, thereby unleashing the fundamental boundaries imposed by conventional linear or circular polarization bases.
View Article and Find Full Text PDFMicrosyst Nanoeng
December 2024
College of Optical and Electronic Technology, China Jiliang University, Hangzhou, 310018, China.
Metasurface with natural static structure limits the development of dynamic metasurface holographic display with rapid response and broadband. Currently, liquid crystal (LC) was integrated onto the metasurface to convert the passive metasuface into an active one. But, majority of LC-assisted active metasurfaces often exhibit trade-offs among degree of freedom (DoF, typically less than 2), information capacity, response speed, and crosstalk.
View Article and Find Full Text PDFIn order to address the issue of low effective bandwidth ratio in off-axis digital holography, which is caused by the impact of zeroth- and first-order terms on the first-order term, an improved digital holographic reconstruction algorithm by zeroth-order term elimination based on the Riesz transform is proposed in this paper. First, an off-axis hologram is convolved with the Riesz kernels. Then, in the spectrum, the zeroth-order term is effectively eliminated by a singularity at the origin of the Riesz kernels, which can improve the effective bandwidth ratio and make the best use of the bandwidth.
View Article and Find Full Text PDFHolographically designed aperiodic lattices (ALs) have proven to be an exciting engineering technique for achieving electrically switchable single- or multi-frequency emissions in terahertz (THz) semiconductor lasers. Here, we employ the nonlinear transfer matrix modeling method to investigate multi-wavelength nonlinear (sum- or difference-) frequency generation within an integrated THz (idler) laser cavity that also supports optical (pump and signal) waves. The laser cavity includes an aperiodic lattice, which engineers the idler photon lifetimes and effective refractive indices.
View Article and Find Full Text PDFAerosp Med Hum Perform
November 2024
Introduction: As next-generation space exploration missions require increased autonomy from crews, real-time diagnostics of astronaut health and performance are essential for mission operations, especially for determining extravehicular activity readiness. An augmented reality (AR) system may be a viable tool allowing holographic visual cueing to replace physical objects used in traditional assessments.
Methods: In this study, 20 healthy adults were compared in an Ingress and Egress Task and Obstacle Weave Task with holographic and physical objects to determine the effect of AR on performance.
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