ABSTRACT
This chapter describes a method for detecting the alignment direction of micro-particles floating in water via magnetic orientation. This is followed by a discussion of optical and magnetic properties of biogenic micro-mirror particles. The chapter focuses on correlations between micro-crystal alignment directions and combinations of magnetic field, incident light, and observation direction. The micro-crystals include uric acid, biogenic guanine, micro-crystal-like cellulose, calcium carbonate, and hexagonal boron nitride particles, which were artificially prepared or derived from biological and commercial products. Optical fiber-based measurement systems were used with the superconducting magnet or the electromagnet, depending on the magnetic field intensity required. Mimics of fish guanine platelets have potential applications in photonic devices, where control of crystal shape and size is desirable. In bio-crystallization, biogenic guanine crystals may be controlled by other molecules such as proteins, but no such proteins have been identified.
