Third-order Phenomena Research Articles

An Introduction to Nonlinear Integrated Photonics Devices: Nonlinear Effects and Materials.

The combination of integrated optics technologies with nonlinear photonics, which has led to the growth of nonlinear integrated photonics, has also opened the way to groundbreaking new devices and applications. Here we introduce the main physical processes involved in nonlinear photonics applications, and we discuss the fundaments of this research area, starting from traditional second-order and third-order phenomena and going to ultrafast phenomena. The applications, on the other hand, have been made possible by the availability of suitable materials, with high nonlinear coefficients, and/or by the design of guided-wave structures, which can enhance the material's nonlinear properties. A summary of the most common nonlinear materials is presented, together with a discussion of the innovative ones. The discussion of fabrication processes and integration platforms is the subject of a companion article, also submitted for publication in this journal. There, several examples of nonlinear photonic integrated devices to be employed in optical communications, all-optical signal processing and computing, or quantum optics are shown, too. We aimed at offering a broad overview, even if, certainly, not exhaustive. We hope that the overall work could provide guidance for those who are newcomers to this field and some hints to the interested researchers for a more detailed investigation of the present and future development of this hot and rapidly growing field.

ON THE SUBJECT OF AUTOPOIESIS AND ITS BOUNDARIES: DOES THE SUBJECT MATTER?

Two arguments are unfolded against the viability and advisability of applying the notion of autopoiesis to third-order systems. The first argument comes from the domain of psychotherapeutic praxis and elaborates a critique of ‘boundary’ and ‘family’ as third-order phenomena. The second argument, coming from the domain of ethics, uses the paramount individuality of personal consciousness to demonstrate that any third-order human system configured on the metaphor of autopoiesis would necessarily be oppressive, inhuman, and parasocial.