TY  - JOUR
A1  - Andrews, Nicholas L. P.
A1  - Ross, Rachel
A1  - Munzke, Dorit
A1  - van Hoorn, Camiel
A1  - Brzezinski, Andrew
A1  - Barnes, Jack A.
A1  - Reich, Oliver
A1  - Loock, Hans-Peter
T1  - In-fiber Mach-Zehnder interferometer for gas refractive index measurements based on a hollow-core photonic crystal fiber
JF  - Optics express : the international electronic journal of optics
N2  - We describe an in-fiber interferometer based on a gas-filled hollow-core photonic crystal fiber. Expressions for the sensitivity, figure of merit and refractive index resolution are derived, and values are experimentally measured and theoretically validated using mode field calculations. The refractive indices of nine monoatomic and molecular gases are measured with a resolution of delta(ns) < 10(-6). (C)2016 Optical Society of America
Y1  - 2016
U6  - https://doi.org/10.1364/OE.24.014086
SN  - 1094-4087
VL  - 24
SP  - 14086
EP  - 14099
PB  - Optical Society of America
CY  - Washington
ER  - 
TY  - JOUR
A1  - Andrews, N. L. P.
A1  - Ferguson, T.
A1  - Rangaswamy, A. M. M.
A1  - Bernicky, A. R.
A1  - Henning, N.
A1  - Dudelzak, A.
A1  - Reich, Oliver
A1  - Barnes, Jack A.
A1  - Loock, Hans-Peter
T1  - Hadamard-Transform Fluorescence Excitation-Emission-Matrix Spectroscopy
JF  - Analytical chemistry
N2  - We present a fluorescence excitation-emission-matrix spectrometer with superior data acquisition rates over previous instruments. Light from a white light emitting diode (LED) source is dispersed onto a digital micromirror array (DMA) and encoded using binary n-size Walsh functions ("barcodes"). The encoded excitation light is used to irradiate the liquid sample and its fluorescence is dispersed and detected using a conventional array spectrometer. After exposure to excitation light encoded in n different ways, the 2-dimensional excitation-emission-matrix (EEM) spectrum is obtained by inverse Hadamard transformation. Using this technique we examined the kinetics of the fluorescence of rhodamine B as a function of temperature and the acid-driven demetalation of chlorophyll into pheophytin-a. For these experiments, EEM spectra with 31 excitation channels and 2048 emission channels were recorded every 15 s. In total, data from over 3000 EEM spectra were included in this report. It is shown that the increase in data acquisition rate can be as high as [{n(n + 1)}/2]-fold over conventional EEM spectrometers. Spectral acquisition rates of more than two spectra per second were demonstrated.
Y1  - 2017
U6  - https://doi.org/10.1021/acs.analchem.7b02400
SN  - 0003-2700
SN  - 1520-6882
VL  - 89
SP  - 8554
EP  - 8564
PB  - American Chemical Society
CY  - Washington
ER  -