We present a compact and highly-sensitive fiber-optic refractometer based on a high-Q π-phase-shifted fiber-Bragg-grating (πFBG) that is chemically etched to the core of the fiber. Due to the p phase-shift, a strong πFBG forms a high-Q optical resonator and the reflection spectrum features an extremely narrow notch that can be used for highly sensitivity refractive index measurement. The etched...

We consider stable signal recovery in `q quasi-norm for 0 < q ≤ 1. In this problem, given a measurement vector y = Ax for some unknown signal vector x ∈ R and a known matrix A ∈ Rm×n, we want to recover z ∈ R with ‖x − z‖q = O(‖x − x‖q) from a measurement vector, where x∗ is the s-sparse vector closest to x in `q quasi-norm. Although a small value of q is favorable for measuring the distance to...

Confocal microscopy was initially developed to image complex circuits and material defects. Previous imaging studies yielded only qualitative data about the location and number of defects. In the present study, this noninvasive method is used to obtain quantitative information about the Q factor of an optical resonant cavity. Because the intensity of the fluorescent signal measures the number o...

We present a Mach-Zehnder interferometer assisted ring resonator configuration (MARC) to realize transmission spectra with unique spectral signatures and significantly large effective free ranges. Transmission are generated by changing the angular separation between through port drop waveguides of (RR). These comprised several distinct resonance lineshapes including Lorentzian, inverse Lorentzi...

Equation (1) is called the measurement equation. It relates the measured observable variables that provide information on αt. We use Zt ∈ M (pt ×m) to denote the matrix of factor loadings. The Ht ∈M (pt × pt) matrix is the variance-covariance matrix of the measurement noise vector, εt. Equation (2) is called the transition equation. We use Gt ∈ M (m×m) to denote the matrix of factor coefficient...

We report the measurement of the acoustic quality factor of a gram-scale, kilo-hertz frequency superfluid resonator, detected through the parametric coupling to a superconducting niobium microwave cavity. For temperature between 400mK and 50mK, we observe a T−4 temperature dependence of the quality factor, consistent with a 3-phonon dissipation mechanism. We observe Q factors up to 1.4 · 10, co...

We propose a measurement of the electromagnetic form factor ratio of the neutron, GE /G n M, at high four–momentum transfer values of Q 2 = 5.0, 6.8, and 10.2 GeV2 in double polarized semi-exclusive 3 −→ He(~e,e′n)pp scattering in quasi–elastic kinematics by measuring the transverse asymmetry, A⊥, of the cross section. This quantity can then be used to quickly extract the electric form factor, ...

I believe the article by Pianosi (February 1997)1 concerning the measurement of cardiac output using impedance cardiogra¬ phy (ICG) illustrates a potentially serious defect in the evaluation of measurement techniques, related to results calculated using a formula with parameters not directly determined by the pro¬ posed measurement. Specifically, the formula for calculation of cardiac output, Q...