Multimode Fibers for Quantum-Secure Communication

Multimode fibers support a multitude of transverse optical modes. These modes are mixed by the fiber. By complex wavefront shaping through the multimode fiber, we can undo this mixing, making it possible to communicate through the fiber even at very low light levels

Language Typology Trace Based on Motion Events: Javanese Spoken by English Learners

This study aimed at identifying the ways Javanese, one of Austronesian languages, speakers expressed motion events, either using man-ner-incorporating sentences, path-incorporating sentences, or equipollently framing manner and path in the same predication position. The investigated speakers were English learners. Furthermore, the study investigated whether language contact played a role in the lan-guage change. After analyzing data from Javanese speakers learning English, it was revealed that Javanese consultants used mostly man-ner verbs, behaving more like a satellite-framed language, no longer an equipollently-framed. Language contact played a role in the ten-dency alteration of Javanese speakers to produce manner verbs in the predicate position caused by their learning English, which is a sat-ellite-framed language with major construction of manner-incorporating sentences. The result of the study on language typology of Java-nese spoken by English learners could end up showing that language contact in the multilingual contexts might contribute to any lan-guage variation

Spectroscopy of formaldehyde in the 30140-30790cm^-1 range

Room-temperature absorption spectroscopy of formaldehyde has been performed in the 30140-30790cm^-1 range. Using tunable ultraviolet continuous-wave laser light, individual rotational lines are well resolved in the Doppler-broadened spectrum. Making use of genetic algorithms, the main features of the spectrum are reproduced. Spectral data is made available as Supporting Information

Roadmap on optical security

Information security and authentication are important challenges facing society. Recent attacks by hackers on the databases of large commercial and financial companies have demonstrated that more research and development of advanced approaches are necessary to deny unauthorized access to critical data. Free space optical technology has been investigated by many researchers in information security, encryption, and authentication. The main motivation for using optics and photonics for information security is that optical waveforms possess many complex degrees of freedom such as amplitude, phase, polarization, large bandwidth, nonlinear transformations, quantum properties of photons, and multiplexing that can be combined in many ways to make information encryption more secure and more difficult to attack. This roadmap article presents an overview of the potential, recent advances, and challenges of optical security and encryption using free space optics. The roadmap on optical security is comprised of six categories that together include 16 short sections written by authors who have made relevant contributions in this field. The first category of this roadmap describes novel encryption approaches, including secure optical sensing which summarizes double random phase encryption applications and flaws [Yamaguchi], the digital holographic encryption in free space optical technique which describes encryption using multidimensional digital holography [Nomura], simultaneous encryption of multiple signals [Pérez-Cabré], asymmetric methods based on information truncation [Nishchal], and dynamic encryption of video sequences [Torroba]. Asymmetric and one-way cryptosystems are analyzed by Peng. The second category is on compression for encryption. In their respective contributions, Alfalou and Stern propose similar goals involving compressed data and compressive sensing encryption. The very important area of cryptanalysis is the topic of the third category with two sections: Sheridan reviews phase retrieval algorithms to perform different attacks, whereas Situ discusses nonlinear optical encryption techniques and the development of a rigorous optical information security theory. The fourth category with two contributions reports how encryption could be implemented at the nano- or micro-scale. Naruse discusses the use of nanostructures in security applications and Carnicer proposes encoding information in a tightly focused beam. In the fifth category, encryption based on ghost imaging using single-pixel detectors is also considered. In particular, the authors [Chen, Tajahuerce] emphasize the need for more specialized hardware and image processing algorithms. Finally, in the sixth category, Mosk and Javidi analyze in their corresponding papers how quantum imaging can benefit optical encryption systems. Sources that use few photons make encryption systems much more difficult to attack, providing a secure method for authentication.Centro de Investigaciones ÓpticasConsejo Nacional de Investigaciones Científicas y Técnica