Fluence and polarisation dependence of GaAs based Lateral Photo-Dember terahertz emitters

We characterise THz output of lateral photo-Dember (LPD) emitters based on semi-insulating (SI), unannealed and annealed low temperature grown (LTG) GaAs. Saturation of THz pulse power with optical fluence is observed, with unannealed LTG GaAs showing highest saturation fluence at 1.1 ± 0.1 mJ cm-2. SI-GaAs LPD emitters show a flip in signal polarity with optical fluence that is attributed to THz emission from the metal-semiconductor contact. Variation in optical polarisation affects THz pulse power that is attributed to a local optical excitation near the metal contact

ChatGPT: ascertaining the self-evident. The use of AI in generating human knowledge

The fundamental principles, potential applications, and ethical concerns of ChatGPT are analyzed and discussed in this study. Since ChatGPT emerged, it has gained a rapidly growing popularity, with more than 600 million users today. The development of ChatGPT was a significant mile-stone, as it demonstrated the potential of large-scale language models to generate natural language responses that are almost indistinguishable from those of a human. ChatGPT's operational principles, prospective applications, and ability to advance a range of human endeavours are discussed in the paper. However, much of the work discusses and poses moral and other problems that rely on the subject. To document the latter, we submitted 14 queries and captured the ChatGPT responses. ChatGPT appeared to be honest, self-knowledgeable, and careful with its answers. The authors come to the realization that since AI is already a part of society, the pervasiveness of the ChatGPT tool to the general public has once again brought to light concerns regarding AI in general. Still, they have moved from the domain of scientific community collective reflection at a conceptual level to everyday practice this time.Comment: 20 pages, 2 figure