High Performance Photoluminescence Spectroscopy using Fourier Transform Interferometry

1989 ◽  
Vol 163 ◽  
Author(s):  
M.L.W. Thewalt ◽  
M.K. Nissen ◽  
D.J.S. Beckett ◽  
K.R. Lundgren
Keyword(s):  
Fourier Transform ◽  
Spectral Resolution ◽  
High Performance ◽  
Tunable Laser ◽  
High Sensitivity ◽  
Photoluminescence Spectroscopy ◽  
High Spectral Resolution ◽  
Photoluminescence Excitation ◽  
Laser Sources ◽  
Very High

AbstractWe present recent results on the applications of Fourier transform techniques to photoluminescence spectroscopy as it relates to both basic and characterization-related semiconductor research. The emphasis here is on demonstrating the advantages of these methods in situations requiring very high spectral resolution and/or very high sensitivity. We also provide an example of the utility of interferometry in performing photoluminescence excitation spectroscopy in spectral regions where broadly tunable laser sources are not readily available.

scholarly journals Instrument concept of the imaging Fourier transform spectrometer GLORIA

2014 ◽  
Vol 7 (3) ◽  
pp. 2301-2337 ◽  
Author(s):  
F. Friedl-Vallon ◽  
T. Gulde ◽  
F. Hase ◽  
A. Kleinert ◽  
T. Kulessa ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Spectral Resolution ◽  
Lower Stratosphere ◽  
Infrared Region ◽  
High Spectral Resolution ◽  
Fourier Transform Spectrometer ◽  
Upper Troposphere ◽  
Very High Spatial Resolution ◽  
Research Aircraft ◽  
Very High

Abstract. The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an imaging limb emission sounder operating in the thermal infrared region. It is designed to provide measurements of the Upper Troposphere/Lower Stratosphere with high spatial and high spectral resolution. The instrument consists of an imaging Fourier transform spectrometer integrated in a gimbal. The assembly can be mounted in the belly pod of the German high altitude and long range research aircraft HALO and in instrument bays of the Russian M55 Geophysica. Measurements are made predominantly in two distinct modes: the chemistry mode emphasises chemical analysis with high spectral resolution, the dynamics mode focuses on dynamical processes of the atmosphere with very high spatial resolution. In addition the instrument allows tomographic analyses of air volumes. The first measurement campaigns have shown compliance with key performance and operational requirements.

scholarly journals Instrument concept of the imaging Fourier transform spectrometer GLORIA

2014 ◽  
Vol 7 (10) ◽  
pp. 3565-3577 ◽  
Author(s):  
F. Friedl-Vallon ◽  
T. Gulde ◽  
F. Hase ◽  
A. Kleinert ◽  
T. Kulessa ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Spectral Resolution ◽  
Infrared Region ◽  
High Spectral Resolution ◽  
Fourier Transform Spectrometer ◽  
Upper Troposphere ◽  
Very High Spatial Resolution ◽  
Research Aircraft ◽  
Very High ◽  
Made In

Abstract. The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an imaging limb emission sounder operating in the thermal infrared region. It is designed to provide measurements of the upper troposphere/lower stratosphere with high spatial and high spectral resolution. The instrument consists of an imaging Fourier transform spectrometer integrated into a gimbal. The assembly can be mounted in the belly pod of the German High Altitude and Long Range research aircraft (HALO) and in instrument bays of the Russian M55 Geophysica. Measurements are made in two distinct modes: the chemistry mode emphasises chemical analysis with high spectral resolution, and the dynamics mode focuses on dynamical processes of the atmosphere with very high spatial resolution. In addition, the instrument allows tomographic analyses of air volumes. The first measurement campaigns have shown compliance with key performance and operational requirements.

scholarly journals Goals for the Application of High-Resolution X-ray Spectroscopy to the Diagnosis of Stellar Coronal Plasmas

1990 ◽  
Vol 115 ◽  
pp. 94-109 ◽  
Author(s):  
Jeffrey L. Linsky
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
Transient Flow ◽  
Emission Measure ◽  
Active Regions ◽  
High Sensitivity ◽  
High Spectral Resolution ◽  
Spectral Features ◽  
Signal To Noise ◽  
X Ray

AbstractI provide examples of how high-resolution x-ray spectra may be used to determine the temperature and emission measure distributions, electron densities, steady and transient flow velocities, and location of active regions in stellar coronae. For each type of measurement I estimate the minimum spectral resolution required to resolve the most useful spectral features. In general, high sensitivity is required to obtain sufficient signal-to-noise to exploit the high spectral resolution. Although difficult, each measurement should be achievable with the instrumentation proposed for AXAF.

Mercury's Na exosphere as seen with very high spectral resolution from the ground, and from space with MESSENGER

2020 ◽  
Author(s):  
Nelly Mouawad ◽  
Judy Chebly ◽  
François Leblanc ◽  
Jonathan Fraine ◽  
Kahil Fatima
Keyword(s):  
Spectral Resolution ◽  
Doppler Shift ◽  
Space Environment ◽  
High Spectral Resolution ◽  
Polar Regions ◽  
University Of Texas ◽  
Intensity Measurements ◽  
Trajectory Approach ◽  
Space Data ◽  
Very High

<p>The MErcury Surface, Space ENvironment, GEochemistry, and Ranging NASA’s spacecraft, known as MESSENGER, flew by Mercury on September 29, 2009. It was the spacecraft’s third and final flyby, before it went into orbit around the planet. The flyby presented a unique trajectory approach and perspective on the planet’s exosphere, not available when in orbit. We present very high spectral resolution ground-based data obtained at the University of Texas McDonald 2.7-m telescope. These data were acquired within hours of the data taken with the Ultraviolet and Visible Spectrometer (UVVS) onboard MESSENGER. Both datasets targeted similar spatial regions, in the polar altitudes of Mercury. We compare the sodium emissions from both measurements in the exosphere. We find that close to the surface, both intensity measurements match, but the intensities fall off differently with altitude, with the MESSENGER data showing an exponential drop off, sharper than that of the ground-based data; an effect that we attribute to atmospheric seeing. In addition, our ground-based data provided Full Width Half Maximum (fwhm) speeds and Doppler shift speeds; our results suggest energetic processes took place in the polar regions on the dusk side of the planet, but arguably on the dawn side as well. We confirm previous conclusions of Leblanc et al. (2008, 2009) where signatures of energetic processes seem to be coupled with high fwhm speeds and intensity peaks. We compare our Doppler shift velocities with previous works, and find agreement within the uncertainties with Potter et al., (2013) on their transit velocity measurements. Although our peak emissions along the terminator vary in structure and in brightness, they do not exhibit distinctive signatures in the intensity profiles at altitudes above the poles, when compared with convolved MESSENGER space data.</p>

Excitation Spectroscopy of Photoluminescence of a-Si:H

1990 ◽  
Vol 192 ◽  
Author(s):  
S. Q. Gu ◽  
P. C. Taylor
Keyword(s):  
Absorption Spectrum ◽  
Room Temperature ◽  
Tunable Laser ◽  
Excitation Source ◽  
Photoluminescence Excitation ◽  
Dangling Bond ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection ◽  
Very High

Photoluminescence excitation (PLE) spectra at 77 K have been measured over the range 1.201.75 eV using the Ti sapphire cw tunable laser as the excitation source. Two undoped a-Si:H samples on rough substrates have been investigated. The first sample has a very high dangling bond (DB) density; the second one has low DB density. The PLE spectrum of photoluminescence (PL) at 0.8 eV for the first sample follows the shape of the absorption spectrum measured by photothermal deflection spectroscopy (PDS) at room temperature. This behavior can be understood within the context of the existing models as due to recombination through defects which produces PL centered around 0.8 eV. However the PLE spectrum of PL at 0.8 eV for the second sample drops very rapidly with decreasing energy for energies less than about 1.3 eV. This behavior, which differs dramatically from that of the absorption spectrum, is consistent with earlier results and suggests that the PL measured at 0.8 eV for the second sample may be largely due to a contribution of the tail of the PL band which peaks near 1.3 eV. The PLE spectra for PL at 1.0 eV and 1.1 eV for the second sample approach the PLE spectrum previously obtained using the integrated PL intensities.

scholarly journals High-Resolution Fourier Transform Spectroscopy with a VLT

1984 ◽  
Vol 79 ◽  
pp. 497-497
Author(s):  
Donald N.B. Hall
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Spectral Resolution ◽  
Thermal Infrared ◽  
The Other ◽  
High Spectral Resolution ◽  
Resolution Element ◽  
Infrared Wavelengths ◽  
Frequency Calibration ◽  
Absorption Features

The major advantages of the FTS technique are (1) multiplexing, (2) throughput, (3) instrumental profile, (4) stability of frequency calibration, and (5) spectrophotometry accuracy. The multiplex advantage is realized only if one is detector noise limited for the signal within an individual spectral-resolution element. At optical and thermal infrared wavelengths, this is only the case at high spectral resolution (≥ 50000) for modern detectors. By the time the VLT is operating one expects this to also be the case in the 1- to 2.5-micron region. At resolutions ≥ 50000 there are severe problems matching dispersive spectrographs to the VLT aperture, whereas existing FTS instruments already have adequate through-put to match to fields of a few arcsec with a VLT. When the other advantages are considered, the FTS is the instrument of choice for high-resolution (≥ 50000) spectroscopy of absorption features with a VLT. Foreseeable astrophysical applications include observations of interstellar and circumstellar features and of fully resolved profiles of photospheric and planetary lines.

scholarly journals Compact, astigmatism corrected cross-grating spectrometer

2020 ◽  
Vol 238 ◽  
pp. 03005
Author(s):  
Matthias Kraus ◽  
Erik Förster ◽  
Verena Bagusat ◽  
Tobias Hönle ◽  
Xavier Uwurukundo ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Optical Design ◽  
Diffraction Order ◽  
High Spectral Resolution ◽  
Adjustment Process ◽  
Single Shot ◽  
Grating Spectrometer ◽  
Echelle Grating ◽  
Convex Mirror ◽  
Laser Sources

Compact cross-grating spectrometers are inspired by classical high-end Echelle spectrometers and allow to acquire a large spectrum with a high spectral resolution in a single shot. To decrease the size of an Echelle spectrometer substantially, a cross grating was employed combining both required dispersive functionalities. First, an Echelle grating diffracts light in several higher diffraction orders, while a superposed, perpendicularly oriented cross-disperser is used in first diffraction order. In this contribution, we report on the realization of a cross-grating spectrometer employing a folded reflective beam path. A toric-convex mirror was introduced allowing aberration compensation. We present the basic concept and optical design of the system and discuss the mechanical implementation and the adjustment process. Here, different laser sources and gas emission lamps are used to realize the system and derive the optical performance. In particular, the spectral resolution in the different diffraction orders is determined for the realized device.

scholarly journals Wide Swath and High Resolution Airborne HyperSpectral Imaging System and Flight Validation

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1667 ◽  
Author(s):  
Dong Zhang ◽  
Liyin Yuan ◽  
Shengwei Wang ◽  
Hongxuan Yu ◽  
Changxing Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Spectral Resolution ◽  
High Efficiency ◽  
High Spatial Resolution ◽  
Imaging System ◽  
High Sensitivity ◽  
Field Of View ◽  
High Spectral Resolution ◽  
Wide Swath

Wide Swath and High Resolution Airborne Pushbroom Hyperspectral Imager (WiSHiRaPHI) is the new-generation airborne hyperspectral imager instrument of China, aimed at acquiring accurate spectral curve of target on the ground with both high spatial resolution and high spectral resolution. The spectral sampling interval of WiSHiRaPHI is 2.4 nm and the spectral resolution is 3.5 nm (FWHM), integrating 256 channels coving from 400 nm to 1000 nm. The instrument has a 40-degree field of view (FOV), 0.125 mrad instantaneous field of view (IFOV) and can work in high spectral resolution mode, high spatial resolution mode and high sensitivity mode for different applications, which can adapt to the Velocity to Height Ratio (VHR) lower than 0.04. The integration has been finished, and several airborne flight validation experiments have been conducted. The results showed the system’s excellent performance and high efficiency.

scholarly journals Interferometry and Stellar Magnetism

2000 ◽  
Vol 175 ◽  
pp. 174-177 ◽  
Author(s):  
O. Chesneau ◽  
K. Rousselet-Perraut ◽  
F. Vakili
Keyword(s):  
Spectral Resolution ◽  
Angular Resolution ◽  
Zeeman Effect ◽  
High Spectral Resolution ◽  
Sensitivity Threshold ◽  
High Angular Resolution ◽  
Be Stars ◽  
Long Baseline ◽  
Instrumental Polarisation ◽  
Very High

AbstractThe classical detection of magnetic fields in Be stars remains a challenge due to the sensitivity threshold and geometrical cancelation of the field effects. We propose to study the Zeeman effect using Spectro-Polarimetric INterferometry (SPIN) which consists of the simultaneous use of polarimetry and very high angular resolution provided by long baseline interferometers. As monitoring of the instrumental polarisation is mandatory in order to calibrate interferometric observations in any case, the polarised signal is a natural by-product of interferometers. This method will be tested on the GI2T interferometer thanks to its high spectral resolution and its polarimetric capabilities.

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