We developed the electrically color-switchable glass and information displays with electrochromic (EC) nanoparticle thin films. The devices were fabricated with liquid processes with the “ink” of multi-colored EC nanoparticles of Prussian blue and its analogues. The color switchable glass with spin-coated uniform EC films exhibits its color change between stained and colorless under applied voltage less than ±1.5 V. Serious degradation of the device was not observed even after the 10,000 times operations. We also made EC nanoparticle thin film with fine patterns. An EC device with such patterned films shows clear change of displayed image electrically.

We present a technique for atomic density measurements by the off-resonant phase shift induced on a two-frequency, coherently synthesized light beam. We have used this scheme to measure the column density of a magnetically trapped atom cloud and to monitor oscillations of the cloud in real time by making over a hundred non-destructive local density measurements. For measurements using pulses of 10 4 -10 5 photons lasting ∼10 µs, the precision is limited by statistics of the photons and the photodiode avalanche. We explore the relationship between measurement precision and the unwanted loss of atoms from the trap and introduce a figure of merit that characterizes it. This method can be used to probe the density of a Bose-Einstein condensate (BEC) with minimal disturbance of its phase.

We demonstrated that divalent manganese/zinc ions (MnII/ZnII) and ferricyan ion [FeIII(CN)6]3- cooperatively trap the cesium ion in aqueous solution within the self-fabricated cubic nanospace with high efficiency. In the low-Cs+-concentration region (≤100 ppm), addition of 5 mmol/L [Fe(CN)6]3+ and 5 mmol/L MnII/ZnII significantly reduces the Cs+ concentration 0.003/0.008 ppm. In the higher-concentration region, the Cs trapping capacity (T≡MCs/Mhost, where MCs and Mhost are the masses of the trapped cesium and host, respectively) reaches T = 420/410 mg/g above 6 mmol/L. The size matching between the nanospace (5.30/5.20 Å for the Mn/Zn compounds, respectively) and the ionic radius (rCs+ = 1.74 Å) of the guest Cs+ is responsible for the high trapping efficiency.

We found a unique spectroscopic property of silver nanodisks covered with J-aggregate. The spectral hole around the position of the J-band was remarkably observed in the surface plasmon band. The origin of the peculiar phenomenon is presumed to be the suppressive interaction between the surface plasmon and Frenkel exciton.

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