Near-field measurement of amplitude and phase in silicon waveguides with liquid cladding

Heterodyne near-field scanning optical microscopy (H-NSOM) has proven useful as a tool for characterization of both amplitude and phase of on-chip photonic devices in air, but it has previously been unable to characterize devices with a dielectric overcladding, which is commonly used in practice for such devices. Here we demonstrate H-NSOM of a silicon waveguide with a liquid cladding emulating the solid dielectric. This technique allows characterization of practical devices with realistic refractive index profiles. Fourier analysis is used to estimate the effective refractive index of the mode from the measured data, showing an index shift of 0.08 from air to water cladding, which is seen to correspond well to simulations.     

中微子的螺旋度反转

庆祝著名物理学家Maurice Goldhaber百岁生日的文章,该文的作者是Maurice Goldhaber本人(前美国布鲁克海文国家实验室主任)和他的儿子Alfred Scharff Goldhaber(美国纽约大学石溪分校杨振宁理论物理研究所教授).在文章中,Goldhaber父子阐明了粒子的螺旋度和手征性     

On the Prolate Spheroidal Wave Functions and Hardy’s Uncertainty Principle

We prove a weak version of Hardy’s uncertainty principle using properties of the prolate spheroidal wave functions. We describe the eigenvalues of the sum of a time limiting operator and a band limiting operator acting on \(L^2(\mathbb {R})\) . A weak version of Hardy’s uncertainty principle follows from the asymptotic behavior of the largest eigenvalue as the time limit and the band limit approach infinity. An asymptotic formula for this eigenvalue is obtained from its well-known counterpart for the prolate integral operator.     

Minimizing the number of machines for minimum length schedules

In this paper, we present a new objective function for scheduling on parallel machines: minimizing the number of machines for schedules of minimum length. We study its complexity and we prove the NP-completeness of this problem, even if there is no precedences or for unitary execution times. We propose several polynomial algorithms for various particular cases.     

Synthesis of novel fluorinated 4-aminoquinoline derivatives

New 4-aminoquinolines having a -CF₂CH-(heteroaryl)-OH moiety are obtained in moderate yields from the electrochemical catalyzed reaction of the corresponding 4-amino-3-chlorodifluoroacetyl-2-methoxyquinoline in the presence of heteroaryl aldehydes. A one-pot intramolecular zinc mediated aromatic nucleophilic substitution also gave access to novel difluorinated 5-aminodihydropyrano[2,3-b]quinolin-4-ones.