Polygonal silica toroidal microcavity for controlled optical coupling

We fabricated polygonal silica toroidal microcavities to achieve stable mechanical coupling with an evanescent coupler such as a tapered fiber. The polygonal cavity was fabricated by using a combination of isotropic etching, anisotropic etching and laser reflow. It offers both high and low coupling efficiencies with the cavity mode even when the coupler is in contact with the cavity, which offers the possibility of taking the device outside the laboratory. A numerical simulation showed that an octagonal silica toroidal microcavity had an optical quality factor of 8.8\times10^6.Comment: 13 pages, 4 figure

Redshift Dependent Lag-Luminosity Relation in 565 BASTE Gamma Ray Bursts

We compared redshifts $z_Y$ from Yonetoku relation and $z_{lag}$ from the lag-luminosity relation for 565 BASTE GRBs and were surprised to find that the correlation is very low. Assuming that the luminosity is a function of both $z_Y$ and the intrinsic spectral lag $\tau_{lag}$, we found a new redshift dependent lag-luminosity relation as $L=7.5\times 10^{50}{\rm erg/s}(1+z)^{2.53}\tau_{lag}^{-0.282}$ with the correlation coefficient of 0.77 and the chance probability of $7.9\times 10^{-75}$. To check the validity of this method, we examined the other luminosity indicator, Amati relation, using $z_Y$ and the observed fluence and found the correlation coefficient of 0.92 and the chance probability of $5.2\times 10^{-106}$. Although the spectral lag is computed from two channels of BATSE, our new lag-luminosity relation suggests that a possible lag-luminosity relation in the \swift era should also depend on redshift

First Total Synthesis of (+/-)-6 '-Methoxyretrojusticidin B Using Regiocontrolled Benzannulation: Structural Inconsistency with Procumphthalide A and Its Revision to 5 '-Methoxyretrochinensin

We achieved the first total synthesis of a novel (+/-)-6'-methoxyretrojusticidin B, which was proposed as procumphthalide A, utilizing regiocontrolled benzannulation of an aryl(aryl')-2,2-dichlorocyclopropylmethanol as the key step. (1)H NMR spectral data suggested that the structure of the synthesized product, 6'-methoxyretrojusticidin B, was inconsistent with that of natural procumphthalide A. A computational study of the rotational barrier rationally supports the existence of a rigid chiral axis in 6'-methoxyretrojusticidin B. The revised structural elucidation of natural procumphthalide A was concluded to be 5'-methoxyretrochinensin.ArticleSYNLETT. 2010(15):2275-2278 (2010)journal articl