Journal: Journal of the Royal Society Interface

Article Title: Mechanism of variable structural colour in the neon tetra: quantitative evaluation of the Venetian blind model

doi: 10.1098/rsif.2010.0253

Figure Lengend Snippet: Venetian blind model. The longitudinal section of an iridophore is schematically illustrated. There exist many light-reflecting platelets that are tilted at an angle θ with respect to the basal plane of the cell. (a,b) Two different tilt angles. As indicated by a pair of arrows, the spacing between the adjacent platelets is larger in (b) than that in (a). Another difference is noted in the direction of the reflected light. (c) A case when the entire iridophore is tilted by an angle α with respect to the optical axis of the microscope. In fact, our experiments are performed with non-zero α so that the reflected light appears around the centre of the far-field pattern. The inset in (b) shows the definitions of the parameters of the multilayer interference phenomenon. The thicknesses (refraction angle) of the guanine platelet and cytoplasm part are denoted by dg (ϕg) and dc (ϕc), respectively. Further, a constant parameter D = (dg + dc)/sinθ is introduced to represent the distance between two adjacent platelets located on the bottom (or top) surface of the stack.

Article Snippet: The size and thickness of a single light-reflecting platelet were measured by using a commercial interference microscope (Ryoka Systems Inc., V ert S can 2.0).

Techniques: Microscopy

Journal: Journal of the Royal Society Interface

Article Title: Mechanism of variable structural colour in the neon tetra: quantitative evaluation of the Venetian blind model

doi: 10.1098/rsif.2010.0253

Figure Lengend Snippet: Optical system of a microscope that functions both as a microspectrophotometer and as a microscatterometer. Light from a Xe lamp is focused on a 100 µm diameter pinhole placed in the plane of the aperture stop (AS). The pinhole is imaged on the back focal plane of the objective lens so that the illuminating light becomes nearly collimated at the sample position. The real image of the sample is observed with a CCD camera (DP25). Using an optical fibre, the reflected light from a small part is guided into a spectrometer. Another CCD camera (PL-B954HU) observes the intensity pattern of the back focal plane of the objective lens through a beam splitter inside the dual-port unit (U-DP) and a macro zoom lens (model 54 363). A pinhole of a 200 µm diameter is placed in the plane of field stop (FS) to restrict the illuminated area during the measurements. The lower right illustration shows that the sample chamber is placed on the goniometer attached to translation stages.

Article Snippet: The size and thickness of a single light-reflecting platelet were measured by using a commercial interference microscope (Ryoka Systems Inc., V ert S can 2.0).

Techniques: Microscopy

Journal: Journal of the Royal Society Interface

Article Title: Mechanism of variable structural colour in the neon tetra: quantitative evaluation of the Venetian blind model

doi: 10.1098/rsif.2010.0253

Figure Lengend Snippet: The profile of a single light-reflecting platelet. (a) A colour image created by the height data obtained by using an interference microscope. The inset shows the same platelet observed by a normal optical microscope under epi-illumination (scale bar, 10 µm). The height profiles are shown in (b,c), which are obtained along the longitudinal and cross sections, respectively, as indicated by the corresponding letters in (a).

Article Snippet: The size and thickness of a single light-reflecting platelet were measured by using a commercial interference microscope (Ryoka Systems Inc., V ert S can 2.0).

Techniques: Microscopy

Journal: Journal of the Royal Society Interface

Article Title: Mechanism of variable structural colour in the neon tetra: quantitative evaluation of the Venetian blind model

doi: 10.1098/rsif.2010.0253

Figure Lengend Snippet: Tilt angle dependence of the real image and the far-field pattern of the iridophores. By using the goniometer, the sample chamber is tilted through angles of 0° (a,d), 12° (b,e), and 22° (c,f). Photographs (a–c) show the real image of the same part, in which several iridophores containing many blue stacks of the platelets are shown (scale bar, 20 µm). The white circle shows the illuminated area when the far-field patterns are observed. The images (d–f) are the observed far-field patterns corresponding to (a–c). As the sample is tilted, the spot laterally moves as shown in (e) and goes out of the observable angular range in (f). The two inner dotted circles indicate the angles of 15° and 30° with respect to the optical axis of the microscope (the centre of the far-field pattern), and the solid circle indicates the maximum angle 35.7° of the detectable angular range. The plot (g) shows the relation between the tilt angle of the goniometer and the change in the angle of reflection. The line is drawn according to the general relation in specular reflection: the reflection angle is twice the tilt angle.

Article Snippet: The size and thickness of a single light-reflecting platelet were measured by using a commercial interference microscope (Ryoka Systems Inc., V ert S can 2.0).

Techniques: Microscopy