Artifact-metrics authentication is a method to authenticate artifacts that have measurable intrinsic characteristics like microscopic random patterns produced in the manufacturing process. In this study, we use a single-walled carbon nanotube (SWCNT) composite paper that is a composite material made from the mixture of the SWCNTs and the pulp (paper materials), as the material of a new artifact-metrics authentication. Advantages of using SWCNT-composite papers, for example, are easy to handle and to make, and impossible to replicate the patterns. As authentication methods, we focus on the use of Raman spectroscopic characteristics of the SWCNTs, and use features of the distinctive SWCNT patterns in each paper, for authentication "keys." The estimated result of error rate = 10 −5 or less was obtained from an experiment that used combination data obtained from specific Raman peaks of the SWCNTs. Our SWCNT-composite papers also have the other usable properties that can be used for authentication keys, thus we are able to improve authentication accuracy more using those keys.

Composite paper containing single-walled carbon nanotubes (SWNTs) has been employed for artifact-metrics authentication using Raman mapping images for authentication keys. To make the most of SWNT properties for authentication, it is desirable to use the diversity of chiralities for authentication keys. In this study, we explored the application of photoluminescence (PL) imaging of SWNT-composite paper to artifact-metrics authentication. SWNTs were wrapped with carboxymethyl cellulose to activate PL and embedded in paper. PL mapping images of different chiralities were examined for authentication. The authentication accuracy was greatly improved by using three-chirality keys. An estimated error rate as small as 10 −12 was achieved.

Silicon-based luminescent materials have been investigated widely for use in advanced optoelectronic integrated circuits and display devices. We tested the application of such materials and investigated their basic characteristics. In this study, luminescent silicon was produced by photochemical etching. The polarization of the photoluminescence under a right and left circularly polarized laser (Ar+ laser, 488 nm) irradiation was observed at 20–290 K. We found that the right- and left-circularly polarized photoluminescence intensities were intensified under right- and left-circular excitation, respectively. Information on the circular polarization of the laser excitation is apparently preserved in silicon-based luminescent material. This tendency was observed at room temperature. Additionally, a luminescence mechanism is studied by the spin dynamics of the photon-electron interaction.

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