scholarly journals Dual Tunable MZIs Stationary-Wave Integrated Fourier Transform Spectrum Detection

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2352
Author(s):  
Xinyang Chen ◽  
Peijian Huang ◽  
Ning Wang ◽  
Yong Zhu ◽  
Jie Zhang
Keyword(s):  
Fourier Transform ◽  
Signal Reconstruction ◽  
Stationary Wave ◽  
Optical Path Difference ◽  
Path Difference ◽  
High Spectral Resolution ◽  
Reconstruction Method ◽  
Gold Nanowires ◽  
Spectrum Reconstruction ◽  
Under Sampling

In order to resolve spectral alias due to under sampling in traditional stationary-wave integrated Fourier transform (SWIFT) spectrometers, an all-on-chip waveguide based on dual tunable Mach-Zehnder interferometer (MZI) stationary-wave integrated Fourier transform technology (DTM-SWIFT) is proposed. Several gold nanowires are asymmetrically positioned at two sides of zero optical path difference and scatter the interference fringes information, which can avoid aliasing of spectral signals and help to gain high spectral resolution. A systematic theoretical analysis is carried on in detail, including the optical distribution characteristics based on multi-beam interference, stationary-wave theorem and signal reconstruction method based on the FT technology. The results show that the method can complete a resolution of 6 nm for Gauss spectrum reconstruction using only 6 gold nanowires, and a resolution of 5 cm−1 for Raman spectrum reconstruction using 25 gold nanowires.

Gravity anomaly reconstruction based on nonequispaced Fourier transform

Geophysics ◽  
2019 ◽  
Vol 84 (6) ◽  
pp. G83-G92
Author(s):  
Ya Xu ◽  
Fangzhou Nan ◽  
Weiping Cao ◽  
Song Huang ◽  
Tianyao Hao
Keyword(s):  
Fourier Transform ◽  
Compressed Sensing ◽  
Gravity Data ◽  
Signal Reconstruction ◽  
Gaussian Function ◽  
Reconstruction Algorithm ◽  
Data Reconstruction ◽  
Reconstruction Method ◽  
Grid Data ◽  
2D Data

Irregular sampled gravity data are often interpolated into regular grid data for convenience of data processing and interpretation. The compressed sensing theory provides a signal reconstruction method that can recover a sparse signal from far fewer samples. We have introduced a gravity data reconstruction method based on the nonequispaced Fourier transform (NFT) in the framework of compressed sensing theory. We have developed a sparsity analysis and a reconstruction algorithm with an iterative cooling thresholding method and applied to the gravity data of the Bishop model. For 2D data reconstruction, we use two methods to build the weighting factors: the Gaussian function and the Voronoi method. Both have good reconstruction results from the 2D data tests. The 2D reconstruction tests from different sampling rates and comparison with the minimum curvature and the kriging methods indicate that the reconstruction method based on the NFT has a good reconstruction result even with few sampling data.

Design and Characterization of a Fourier Transform Micro-Spectrometer

2009 ◽  
Vol 74 ◽  
pp. 211-214 ◽  
Author(s):  
Shou Hua Wang ◽  
Hong Bin Yu ◽  
Fook Siong Chau ◽  
X.S. Tang
Keyword(s):  
Fourier Transform ◽  
Optical Resolution ◽  
Input Voltage ◽  
Optical Path Difference ◽  
Path Difference ◽  
Optical Path ◽  
Spectral Peaks ◽  
Grating Interferometer ◽  
Diode Pumped

In this paper, we present a Fourier Transform micro-spectrometer which works based on a lamellar grating interferometer. The spectrometer model is electrostatically driven by parallel plate actuators which change the optical path difference (OPD) between movable grating facets and fixed ones. With a 200V input voltage, a maximum OPD of 48.7μm is achieved. The spectrum of a combined light source of a diode-pumped solid-state (DPSS) laser (λ=532.0nm) and a laser diode (λ=637.2nm) is experimentally acquired to demonstrate the performance of the model. The reconstructed spectrum displays two separate spectral peaks at 530.5nm and 635.2nm and the corresponding full-width at half-maximum (FWHM) resolutions are 9.8nm and 12.8nm respectively, indicating good wavelength accuracy and optical resolution.

scholarly journals Simultaneous ground-based observations of O<sub>3</sub>, HCl, N<sub>2</sub>O, and CH<sub>4</sub> over Toronto, Canada by three Fourier transform spectrometers with different resolutions

2007 ◽  
Vol 7 (5) ◽  
pp. 1275-1292 ◽  
Author(s):  
D. Wunch ◽  
J. R. Taylor ◽  
D. Fu ◽  
P. Bernath ◽  
J. R. Drummond ◽  
...  
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Optical Path Difference ◽  
Path Difference ◽  
Optical Path ◽  
Lower Sensitivity ◽  
Critical Importance ◽  
The Difference ◽  
Total Column ◽  
Better Than

Abstract. An intercomparison of three Fourier transform spectrometers (FTSs) with significantly different resolutions is presented. The highest-resolution instrument has a maximum optical path difference of 250 cm, and the two lower-resolution instruments have maximum optical path differences of 50 cm and 25 cm. The results indicate that the two lower-resolution instruments can retrieve total column amounts of O3, HCl, N2O and CH4 using the SFIT2 retrieval code with percent differences from the high-resolution instrument generally better than 4%. Total column amounts of the stratospheric species (O3 and HCl) have larger differences than those of the tropospheric species (N2O and CH4). Instrument line shape (ILS) information is found to be of critical importance when retrieving total columns of stratospheric gases from the lower-resolution instruments. Including the ILS information in the retrievals significantly reduces the difference in total column amounts between the three instruments. The remaining errors for stratospheric species total column amounts can be attributed to the lower sensitivity of the lower-resolution FTSs to the stratosphere.

Spectrum Reconstruction Method for Airborne Temporally–Spatially Modulated Fourier Transform Imaging Spectrometers

2014 ◽  
Vol 52 (6) ◽  
pp. 3720-3728 ◽  
Author(s):  
Lijuan Su ◽  
Yan Yuan ◽  
Bin Xiangli ◽  
Fengzhen Huang ◽  
Jun Cao ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Reconstruction Method ◽  
Spectrum Reconstruction

Calculations on Optical Path Difference of a High Resolution Reflecting Scanning Fourier Transform Spectrometry

2011 ◽  
Vol 31 (7) ◽  
pp. 0730001 ◽  
Author(s):  
魏儒义 Wei Ruyi ◽  
张学敏 Zhang Xuemin ◽  
周锦松 Zhou Jinsong ◽  
周泗忠 Zhou Sizhong ◽  
高晓惠 Gao Xiaohui ◽  
...  
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Optical Path Difference ◽  
Path Difference ◽  
Optical Path ◽  
Fourier Transform Spectrometry

scholarly journals The mechanical and thermal setup of the GLORIA spectrometer

2014 ◽  
Vol 7 (11) ◽  
pp. 10965-11010 ◽  
Author(s):  
C. Piesch ◽  
C. Sartorius ◽  
F. Friedl-Vallon ◽  
T. Gulde ◽  
S. Heger ◽  
...  
Keyword(s):  
High Performance ◽  
Cooling System ◽  
Infrared Emission ◽  
Optical Path Difference ◽  
Path Difference ◽  
High Spectral Resolution ◽  
Linear Slide ◽  
Compact Design ◽  
Trace Constituents ◽  
Performance Results

Abstract. The novel airborne Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) measures infrared emission of atmospheric trace constituents. GLORIA comprises a cooled imaging Fourier transform spectrometer which is operated in unpressurized aircraft compartments at ambient temperature. The whole spectrometer is pointed by the gimbal towards the atmospheric target. In order to reach the required sensitivity for atmospheric emission measurements the spectrometer optics needs to operate at a temperature below 220 K. A lightweight and compact design is mandatory due to limited space and high agility requirements. The cooled optical system needs to withstand high pressure and temperature gradients, humidity, and vibrations. A new cooling system based on carbon dioxide and liquid nitrogen combined with high-performance insulation has been developed to meet the mechanical, thermal, and logistical demands. The challenging mechanical and spatial requirements lead to the development of a novel rigid linear slide design in order to achieve the large optical path difference for high spectral resolution. This paper describes the mechanical and thermal setup of GLORIA and presents the performance results on two different research aircrafts.

scholarly journals The mechanical and thermal setup of the GLORIA spectrometer

2015 ◽  
Vol 8 (4) ◽  
pp. 1773-1787 ◽  
Author(s):  
C. Piesch ◽  
C. Sartorius ◽  
F. Friedl-Vallon ◽  
T. Gulde ◽  
S. Heger ◽  
...  
Keyword(s):  
High Performance ◽  
Cooling System ◽  
Infrared Emission ◽  
Optical Path Difference ◽  
Path Difference ◽  
High Spectral Resolution ◽  
Linear Slide ◽  
Compact Design ◽  
Trace Constituents ◽  
Performance Results

Abstract. The novel airborne Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) measures infrared emission of atmospheric trace constituents. GLORIA comprises a cooled imaging Fourier transform spectrometer, which is operated in unpressurized aircraft compartments at ambient temperature. The whole spectrometer is pointed by the gimbal towards the atmospheric target. In order to reach the required sensitivity for atmospheric emission measurements, the spectrometer optics needs to operate at a temperature below 220 K. A lightweight and compact design is mandatory due to limited space and high agility requirements. The cooled optical system needs to withstand high pressure and temperature gradients, humidity, and vibrations. A new cooling system based on carbon dioxide and liquid nitrogen combined with high-performance insulation has been developed to meet the mechanical, thermal, and logistical demands. The challenging mechanical and spatial requirements lead to the development of a novel rigid linear slide design in order to achieve the large optical path difference for high spectral resolution. This paper describes the mechanical and thermal setup of GLORIA and presents the performance results on two different research aircrafts.

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