Kazuko Koyama

High collection efficiency in fluorescence microscopy with a solid immersion lens

High efficiency of light collection was demonstrated by applying solid immersion lenses (SILs) with refractive indices n=1.845 and 1.687 to fluorescence microscopy of 0.11-μm-radius dye-doped polystyrene sphere beads. This was analyzed with theories on the radiation of dipoles near the surface of the dielectric medium. The estimated collection efficiency with the NA=0.8 objective and the n=1.845 SIL was about 60%–70%, which well exceeds the diffraction-limit value of 50% for 2π-solid angle collection in conventional methods.

Fourier imaging study of efficient near-field optical coupling in solid immersion fluorescence microscopy

We measured images and Fourier images of fluorescence for 0.11- and 0.22-μm-diameter dye-doped polystyrene microsphere beads on a solid immersion lens, and experimentally verified strongly angle-dependent fluorescence intensities due to efficient near-field optical coupling in solid immersion fluorescence microscopy. The results are interpreted in comparison with calculated emission patterns of an emission dipole placed near a solid surface, which establish a basic model for high-collection efficiency in solid-immersion fluorescence microscopy.

Homogeneous line width of Praseodymium ions in various inorganic materials

Persistent spectral hole burning and fluorescence line narrowing spectroscopy was applied to Pr 3+ doped silicate glass, yttria stabilized zirconia, and yttria, to investigate homogeneous line width (Γ). In the temperature (T) dependence of Γ, T-linear components are commonly found below 10 K in these three materials, and their magnitudes are found to become larger as the degree of disorder increases

Improved High Collection Efficiency in Fluorescence Microscopy with a Weierstrass-Sphere Solid Immersion Lens.

We investigate improvements of the collection efficiency in fluorescence microscopy with a Weierstrass-sphere solid immersion lens (SIL). Using a Weierstrass-sphere SIL with refractive index n=1.845 and an objective lens with 0.55 numerical aperture, we demonstrate the high collection efficiency of fluorescence from 0.11-µm-diameter dye-doped microsphere bead samples, which is 21 times higher than that measured in conventional microscopy and is estimated to be 76%. Illumination uniformity and aberrations in Weierstrass-sphere SILs are also evaluated.

Mapping of site distribution in Eu3+:YAlO3 on RF-optical frequency axes by using double-resonance spectroscopy

Abstract We measured the high-resolution excitation spectrum and optical-RF (radio frequency) double-resonance spectra of Eu 3+ : YAlO 3 in 7 F 0 → 5 D 0 region at about 2K. Optical excitation spectrum showed more than 40 weak satellite lines spreading over some 400GHz. These lines are ascribed to the sites differently perturbed by defects or other Eu3+ ions. Using optical-RF double-resonance measurement in the main and some satellite lines, we have obtained RF double-resonance frequencies of hyperfine transition in ground states at various optical frequencies. From these results we can identify the sites which cannot be distinguished by a simple optical measurement.

Role of alkali ions on persistent hole burning in Pr3+-doped germanate glasses

Abstract The effect of a Na2O network modifier on the persistent spectral hole burning of Pr3+ ions has been investigated in (GeO2)1 − x-(Na2O)x glasses for x=0−0.35. The homogeneous linewidth increased twice by adding 35 mol% Na2O. The hole burning efficiency was found to increase about 8 times by adding the same amount of Na2O. These observations are interpreted by considering coupling of the optical centers with the TLS introduced by Na2O doping.

Magnetism and Interlayer Distance of MnPS3 Controlled by Intercalation and Applying High Pressure

We have investigated the change of magnetism of the transition metal phosphorous trisulfide MnPS3 by controlling the interlayer distance, which was varied by intercalation and by applying high pressure. A perfect pyridine intercalation into MnPS3 was achieved by stirring at 373 K for 8 hours. The interlayer distance d of this intercalated phase (P1.9) is 1.9 times lager than that of MnPS3. Furthermore, a new intercalated phase (P2.7), where d is 2.7 times larger than that of MnPS3, was obtained. The latter phase is unstable and changed to a new phase (P2.0) with a d value which is 2.0 times larger than that of MnPS3 by leaving it in air for about 10 minutes. The temperature dependence of the magnetization of P1.9 shows ferrimagnetism with a Curie temperature TC of 40 K, while MnPS3 is an antiferromagnet with a Neel temperature TN of 78 K. High pressure X‐ray diffraction measurements show that the interlayer separation decreases rapidly with increasing pressure (∼ 1%/GPa). This is explained well by the wea...

Luminescence side bands due to distributed Stark levels in Pr3+ : ZrO2−Y2O3 (YSZ)

Abstract In Pr 3+ : ZrO 2 −Y 2 O 3 , luminescence side bands are observedaround resonant fluorescence under excitation at 6142A˚. The behavior of the side bands with changing temperature is successfully explained by assuming that the lower state of the transition splits into three Stark levels which are in thermal equilibrium.

Efficient light-collection effect in fluorescence microscopy with solid immersion lens

Summary form only given. Improved light-collection efficiency and spatial resolution in fluorescence microscopy higher than the diffraction-limit values in the conventional methods have been simultaneously realized by means of a solid immersion lens (SIL), for which we investigate the relevant physics of the efficient light-collection effect. This technique should be very useful in the fluorescence microscopy of semiconductor nano-structures, single dye molecules and various applications in molecular biology.

Two kinds of spectral holes burned in Eu3+ doped β″-alumina

Abstract Two kinds of holes were burned simultaneously in the 7F0-5D0 absorption band of Eu 3+: β″-alumina. They differ in hole width, stability and burning-rate. It was possible to separate the hole spectra into these two components using the difference of stability, and their widths could be obtained individually.