Topic
Optical polarization
About: Optical polarization is a research topic. Over the lifetime, 13992 publications have been published within this topic receiving 244284 citations.
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TL;DR: Optical polarization of 3 He generates large nuclear spin magnetizations, allowing MR imaging of the gas spaces of human and animal lungs despite the low number of spins in the gas as mentioned in this paper.
Abstract: Optical polarization of 3 He generates large nuclear spin magnetizations, allowing MR imaging ofthe gas spaces ofhuman and animal lungs despite the low number den- sity ofspins in the gas. The atomic physics ofoptical pumping and spin exchange is explained; the hardware for polarizing, transporting, and imaging is detailed. Pulse sequences for optimum use of the nonrenewable magnetization require a different imaging strategy than traditional proton MRI. Examples are discussed for static lung images, diffusion images for characteriza- tion ofthe local alveolar structure, and high temporal resolution images. © 2001 John Wiley &
115 citations
TL;DR: A mid-IR highly tunable optical polarization converter composed of asymmetric graphene nanocrosses that can convert linearly polarized light to circularly and elliptically polarized light or exhibit a giant optical activity at different wavelengths is presented.
Abstract: We present a mid-IR highly tunable optical polarization converter composed of asymmetric graphene nanocrosses. It can convert linearly polarized light to circularly and elliptically polarized light or exhibit a giant optical activity at different wavelengths. The transmitted wavelength and polarization states can also be dynamically tuned by varying the Fermi energy of graphene, without reoptimizing and refabricating the nanostructures. This offers a further step in developing a controllable polarization converter.
115 citations
TL;DR: A spectral interference law is derived that governs the behavior of the four Stokes parameters in Young's two-pinhole experiment with a random electromagnetic beam and three new contrast parameters are introduced that describe the interference-induced changes in the field's state of partial polarization.
Abstract: We derive a spectral interference law that governs the behavior of the four Stokes parameters in Young's two-pinhole experiment with a random electromagnetic beam. In addition to the visibility of intensity fringes, we introduce three new contrast parameters that describe the interference-induced changes in the field's state of partial polarization. The polarization modulation depends on the electric field correlations at the pinholes and is closely related to the two-point Stokes parameters. The results are expected to be particularly useful in polarization interferometry and electromagnetic coherence theory. The formalism is demonstrated with specific examples.
115 citations
TL;DR: A dual encryption/decryption scheme, motivated by recent interest in polarization encoding, that provides large flexibility in the key encryption design and immunity to brute force attacks is proposed.
Abstract: We propose and analyze a dual encryption/decryption scheme, motivated by recent interest in polarization encoding. Compared to standard optical encryption methods, which are based on phase and amplitude manipulation, this encryption procedure relying on Mueller-Stokes formalism provides large flexibility in the key encryption design. The effectiveness of our algorithm is discussed, thanks to a numerical simulation of the polarization encryption/decryption procedure of a 256 gray-level image. Of additional special interest is the immunity of this encryption algorithm to brute force attacks.
115 citations
TL;DR: In this article, an all-optical waveform sampling system with simultaneous submilliwatt optical signal sensitivity (20dB signal-to-noise ratio) and sub-picosecond temporal resolution over more than 60-nm optical bandwidth is demonstrated.
Abstract: An all-optical waveform sampling system with simultaneous submilliwatt optical signal sensitivity (20-dB signal-to-noise ratio) and subpicosecond temporal resolution over more than 60-nm optical bandwidth is demonstrated in this paper. The optical sampling was implemented by four-wave mixing in a 10-m highly nonlinear fiber using a sampling pulse source with a sampling pulse peak power of only 16 W. The sampling performance was evaluated in terms of sensitivity, temporal resolution, and optical bandwidth with respect to fiber length, sampling pulse source wavelength offset from the zero-dispersion wavelength of the highly nonlinear fiber, sampling pulse peak power, and walk-off due to chromatic dispersion. This paper also presents a summary of the available methods to achieve polarization-independent optical sampling as well as a brief summary of the available sampling pulse sources viable for optical sampling.
115 citations