More Like this

1. On the Direction of Innovation

   https://doi.org/10.1086/714093  

   Hopenhayn, Hugo; Squintani, Francesco (July 2021, Journal of Political Economy)
2. Direction‐Controlled Bifunctional Metasurface Polarizers

   https://doi.org/10.1002/lpor.201800198  

   Chen, Yang; Gao, Jie; Yang, Xiaodong (October 2018, Laser & Photonics Reviews)

   Abstract Metasurfaces composed of in‐plane subwavelength nanostructures have unprecedented capability in manipulating the amplitude, phase, and polarization states of light. Here, a unique type of direction‐controlled bifunctional metasurface polarizer is proposed and experimentally demonstrated based on plasmonic stepped slit‐groove dimers. In the forward direction, a chiral linear polarizer is enabled which only allows the transmission of a certain incident handedness and converts it into the specified linear polarization. In the backward direction, the metasurface functions as an anisotropic circular polarizer to selectively convert a certain linear polarization component into the desired circularly polarized transmission. The observed direction‐controlled polarization selection and conversion are explained by the spin‐dependent mode coupling process inside the bilayer structure. Anisotropic chiral imaging based on the proposed metasurface polarizer is further demonstrated. The results provide new degrees of freedom to realize future multifunctional photonic integrated devices for structured light conversion, vector beam generation, optical imaging and sensing, and optical communication. 

   more » « less
3. On the Direction of Innovation

   Hopenhayn, Hugo; Squintani, Francesco (July 2021, Journal of political ecology)

   How are resources allocated across different R\&D areas, i.e. problems to be solved? As a result of dynamic congestion externalities, the competitive market allocates excessive resources into those of high return, being those with higher private (and social) payoffs. Good problems are tackled too soon, and as a result the distribution of open research problems in the socially optimal solution stochastically dominates that of the competitive equilibrium. Asevere form of rent dissipation occurs in the latter, where the total value of R\&D activity equals the value of allocating all resources to the least valuable problem solved. Resulting losses can be substantial. 

   more » « less
4. Speed–direction description of turbulent flows

   https://doi.org/10.1063/5.0031218  

   Olshanskii, Maxim A. (November 2020, Physics of Fluids)
5. Turbulent Cascade Direction and Lagrangian Time-Asymmetry

   https://doi.org/10.1007/s00332-018-9476-8  

   Drivas, Theodore D. (February 2019, Journal of Nonlinear Science)

   null (Ed.)