This paper investigates the effect of CFO gender on corporate financial reporting decision-making. Focusing on firms that experience changes of CFO from male to female, the paper compares the firms' degree of accounting conservatism between pre-and post-transition periods. We find that female CFOs are more conservative in their financial reporting. In addition, we find that the relation between CFO gender and conservatism varies with the levels of various firm risks such as litigation risk, default risk, systematic risk, and CFO specific risk such as job security risk. We further find that risk-aversion of female CFOs is associated with less equity-based compensation, lower firm risk, higher tangibility level, and lower dividend payout level. Overall, the study provides strong support for the notion that female CFOs are more risk averse than male CFOs, which leads female CFOs to adopt more conservative financial reporting policies.

we have investigated the influence of multimode fiber core (MMFC) diameters and lengths on the sensitivity of an SMS fiber based refractometer. We show that the MMFC diameter has significant influence on the refractive index (RI) sensitivity but the length does not. A refractometer with a lower MMFC diameter has a higher sensitivity. Experimental investigations achieved a maximum sensitivity of 1815 nm/ RIU (refractive index unit) for a refractive index range from 1.342 to 1.437 for a refractometer with a core diameter of 80 µm. The experimental results fit well with the numerical simulation results. fiber Bragg grating and multimode fibers using an intensity-based interrogation method", 2008 Optical Society of America

We propose and experimentally demonstrate an enhanced evanescent field fiber refractometer based on a tapered multimode fiber sandwiched between two single-mode fibers. Experiments show that this fiber sensor offers ultrahigh sensitivity [better than 1900 nm/RIU at a refractive index (RI) of 1.44] for RI measurements within the range of 1.33-1.44, in agreement with the theoretical predictions. This is the highest value reported to date (to our knowledge) in the literature.

Plasmonic nanolasers have ushered in a paradigm of deep sub-wavelength coherent optical sources with ultrafast dynamics that exploit the strong confinement capabilities of metals. Although these devices are usually associated with higher thresholds due to absorption in metals, the high gain inorganic II-VI and III-V semiconductor materials have allowed the realization of plasmonic nanolasers operating under ambient conditions. In this work, we introduce single-crystalline lead halide perovskite (CHNHPbI) nanowires as an organic-inorganic semiconducting gain material to the plasmonic laser community. We demonstrate plasmonic laser action using a hybrid geometry whereby the perovskite nanowires are placed on a silver substrate with an insulating spacer layer. We report relatively low threshold operation under ambient conditions (13.5 μJ cm), and the devices work well even at temperatures up to 43.6 °C. The demonstration highlights the high optical gain achievable in perovskite materials and thus provides a solution to high gain materials for plasmonic devices.

We report a study of a gallium phosphide, hemispherical, solid immersion lens through the imaging of 40-nm-diam fluorescent dye balls. A spatial resolution as small as 139 nm has been achieved at a wavelength of 560 nm, which is equivalent to a diffraction-limited system of numerical aperture 2.0. This resolution is a 33% improvement over conventional oil immersion objectives and previously reported solid immersion lenses, which typically have a numerical aperture around 1.5.

We report the observation of a sharp absorption line in the photoluminescence excitation spectra of individual naturally occurring quantum dots in a narrow (2.8 nm) GaAs͞Al 0.3 Ga 0.7 As quantum well that is remarkably constant throughout the sample. We propose that it is identified as the delocalized two-dimensional exciton. This assignment is confirmed by photoluminescence and photoluminescence excitation diffusion experiments.

A comprehensive theoretical model for an SMF28-Small-Core SMF (SCSMF) -SMF28 structure based refractometer is developed based on modal propagation analysis (MPA) method. Simulation result shows that the wavelength shift of this refractometer obeys changes exponentially as the surrounding refractive index (SRI) varies. The core diameter of SCSMF does not have a significant influence on the sensitivity of the refractometer but cladding diameter does have. The simulation results are verified experimentally and it is also experimentally demonstrated that a maximum sensitivity of 1808 nm/RIU (refractive index unit) for an SRI range from 1.324 to 1.431 and that as expected the wavelength shift response is an exponential function of SRI.

A refractive index (RI) sensor based on a novel fiber structure which consists of a singlemode-multimodesinglemode (SMS) fiber structure followed by a fiber Bragg grating (FBG) was demonstrated. The multimode fiber (MMF) in the SMS structure excites cladding modes within output singlemode fiber (SMF) and re-couple the reflected cladding Bragg wavelength to the input SMF core. By measuring the relative Bragg wavelength shift between core and cladding Bragg wavelengths, the RI can be determined. Experimentally we have achieved a maximum sensitivity of 7.33 nm/RIU (RI unit) at RI range from 1.324to 1.439.