Multi-purpose nonlinear optical microscope. Its principle and applications to polar thin-film observation

Abstract

Multi-purpose nonlinear optical microscope is an optical microscope which images 2D distribution of the optical second harmonic (SH) waves from a specimen. Image contrast can be obtained either by inhomogeneous distribution of nonlinear optical tensor components or by the interference between SH waves from a specimen and a standard plate. This microscope also functions as a fluorescence (FL) microscope, and SH and FL images can be obtained from the same part of a specimen. Absorption and FL spectra from a specific part of a specimen are measured through an optical fiber which connects an ocular with a polychromator. These functions are especially useful for investigation of the J-aggregate state of polar dye molecules. Several photographs taken by the microscope revealed the structure of merocyanine dye/arachidic acid mixed monolayer and the role of bridge ions in the subphase.