A Photodiode Array Fourier Transform Spectrometer Based on a Birefringent Interferometer

1986 ◽  
Vol 40 (5) ◽  
pp. 691-695 ◽  
Author(s):  
Takayuki Okamoto ◽  
Satoshi Kawata ◽  
Shigeo Minami
Keyword(s):  
Fourier Transform ◽  
Light Emitting Diode ◽  
Emission Spectra ◽  
Fourier Transform Spectrometer ◽  
Mercury Lamp ◽  
Visible Spectroscopy ◽  
Light Emitting ◽  
Common Path ◽  
Wollaston Prism ◽  
Photodiode Array

A new version of the photodiode array Fourier transform spectrometer for visible spectroscopy is described. In this version, a birefringent interferometer with a Wollaston prism produces a spatial interferogram of the radiation, which is detected by a linear photodiode array. In addition to the merit of having no mechanical moving parts, this spectrometer has the beneficial advantage of the simple and rugged optical setup and alignment due to its common-path and in-line interferometer formation. These advantages lend this spectrometer to field-use applications. Emission spectra of a low-pressure mercury lamp and a light-emitting diode and an absorption spectrum of a didymium glass filter measured by the developed spectrometer are presented.

scholarly journals Enhanced Static Modulated Fourier Transform Spectrometer for Fast Approximation in Field Application

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3312
Author(s):  
Ju Yong Cho ◽  
Won Chun Oh ◽  
Won Kweon Jang
Keyword(s):  
Fourier Transform ◽  
Light Emitting Diode ◽  
Spectral Width ◽  
Peak Shift ◽  
Field Application ◽  
Spectral Peak ◽  
Fourier Transform Spectrometer ◽  
Data Sampling ◽  
Light Emitting ◽  
Operating Current

We discuss the data sampling frequency, the spectral resolution, and the limit for non-aliasing in the static modulated Fourier transform spectrometer based on a modified Sagnac interferometer. The measurement was performed in a very short 4 ms, which is applicable for real time field operation. The improved spectrometer characteristics were used to investigate the spectral properties of an InGaAs light emitting diode. In addition, The measured spectral peak was shifted from 6420 cm−1 to 6365 cm−1, as the temperature increased from 25 °C to 40 °C, when the operating current is fixed to be 0.55 A. As the applied current increased from 0.30 A to 0.55 A at room temperature, the spectral width was broadened from 316 cm−1 to 384 cm−1. Compared to the conventional Fourier transform spectrometer, the measured spectral width by the static modulated Fourier transform spectrometer showed a deviation less than 10%, and the spectral peak shift according to the temperature rise showed a difference within 2%.

Light-emitting-diode Fourier-transform spectroscopy of HD16O between 11200 and 12400 cm-1

2015 ◽  
Author(s):  
L. N. Sinitsa ◽  
V. I. Serdyukov ◽  
E. R. Polovtseva ◽  
A. P. Shcherbakov ◽  
A. D. Bykov ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Light Emitting Diode ◽  
Fourier Transform Spectroscopy ◽  
Light Emitting

scholarly journals Analysis of new species retrieved from MIPAS

2014 ◽  
Vol 56 ◽  
Author(s):  
Shaomin Cai ◽  
Anu Dudhia
Keyword(s):  
Fourier Transform ◽  
New Species ◽  
High Resolution ◽  
Trace Gases ◽  
Michelson Interferometer ◽  
Emission Spectra ◽  
Fourier Transform Spectrometer ◽  
Mid Infrared ◽  
The Third ◽  
Atmospheric Sounding

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument which operated on the Envisat satellite from 2002-2012 is a Fourier transform spectrometer for the measurement of high-resolution gaseous emission spectra at the Earth's limb. It operates in the near- to mid-infrared, where many of the main atmospheric trace gases have important emission features. The initial operational products were profiles of Temperature, H2O, O3, CH4, N2O, HNO3, and NO2, and this list was recently extended to include N2O5, ClONO2, CFC-11 and CFC-12. Here we present preliminary results of retrievals of the third set of species under consideration for inclusion in the operational processor: HCN, CF4, HCFC-22, COF2 and CCl4.

Electrostatic Discharge Characteristics of InGaN/GaN Light-Emitting Diodes with Si-Doped Graded Superlattice

2015 ◽  
Vol 15 (10) ◽  
pp. 7733-7737 ◽  
Author(s):  
Kwanjae Lee ◽  
Cheul-Ro Lee ◽  
Jin Soo Kim ◽  
Jin Hong Lee ◽  
Kee Young Lim ◽  
...  
Keyword(s):  
Light Emission ◽  
Electrostatic Discharge ◽  
Light Emitting Diode ◽  
Emission Spectra ◽  
Small Variation ◽  
Injection Current ◽  
Light Emitting ◽  
Current Voltage ◽  
Gan Led ◽  
Si Doped

We report the influences of a Si-doped graded superlattice (SiGSL) on the electrostatic discharge (ESD) characteristics of an InGaN/GaN light-emitting diode (LED). For comparison, a conventional InGaN/GaN LED (C-LED) was also investigated. The luminous efficacy for the SiGSL-LED was 2.68 times stronger than that for the C-LED at the injection current of 20 mA. The resistances estimated from current–voltage (I–V) characteristic curves were 16.5 and 8.8 Ω for the C-LED and SiGSL-LED, respectively. After the ESD treatment at the voltages of 4000 and 6000 V, there was no significant change in the I–V curves for the SiGSL-LED. Also, there was small variation in the I–V characteristics for the SiGSL-LED at the ESD voltage of 8000 V. However, the I–V curves for the C-LED were drastically degraded with increasing ESD voltage. While the light emission was not observed at the injection current of 20 mA from the C-LED sample after the ESD treatment, the emission spectra for the SiGSL-LED sample were clearly measured with the output powers of 10.47, 9.66, and 7.27 mW for the ESD voltages of 4000, 6000, and 8000 V respectively.

Preparation and Luminescence Properties of Polymeric 2,5-Bis[2´-(8´´-alkoxyquinolin-2´´-yl)ethenyl]hydroquinone Derivatives

2002 ◽  
Vol 55 (8) ◽  
pp. 499 ◽  
Author(s):  
M.-A. Hsu ◽  
T. J. Chow
Keyword(s):  
Reduction Potential ◽  
Light Emitting Diode ◽  
Monomer Unit ◽  
Green Light ◽  
Emission Spectra ◽  
Coupling Reaction ◽  
Hydroxyl Groups ◽  
High Solubility ◽  
Light Emitting ◽  
Coumarin 6

A PPV-type polymer (1) incorporating 5,5�-diquinolinyl moieties is prepared by a Yamamoto homo-coupling reaction from the dibromide (2). Since all the hydroxyl groups were alkylated, this polymer showed high solubility in most organic solvents. It can be spin-coated readily to form a thin layer in the fabrication of light emitting diode (LED) devices. The adjacent quinoline rings are twisted to form a dihedral angle due to steric hindrance, so that π-conjugation is confined within each monomer unit. The emission spectra of (1) and (2) are nearly identical. The reduction potential of (1) was estimated to be –1.10 V (onset), with a band gap of 2.53 eV (490 nm). A single hetero-junction LED device fabricated by combining the films of poly(vinylkarbazol) (PVK) and (1) yielded promising results. The device ITO/PVK/(1)/Ca/Al exhibited a turn-on voltage at 6 V and reached a maximal brightness of 250 cd/m2 at 15 V. An alternate potential usage of (1) as an electron-injecting material was also explored on a green-light device using coumarin-6 as an emitter.

Fourier transform spectrometer with a self-scanning photodiode array

1984 ◽  
Vol 23 (2) ◽  
pp. 269 ◽  
Author(s):  
Takayuki Okamoto ◽  
Satoshi Kawata ◽  
Shigeo Minami
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Spectrometer ◽  
Photodiode Array

Color Tunability of Blue Phosphors by Changing Cations for Near-UV InGaN-Based Light-Emitting Diode

2014 ◽  
Vol 986-987 ◽  
pp. 156-159
Author(s):  
Yi Wen Zhu ◽  
Fen Fen Hu ◽  
Mei Li Zhou ◽  
Ping Chen ◽  
Zheng Liang Wang
Keyword(s):  
Uv Light ◽  
Light Emitting Diode ◽  
Blue Emission ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Blue Shift ◽  
Ionic Radii ◽  
Light Emitting ◽  
Triclinic Structure ◽  
The Difference

The serials of blue phosphors, CaAl2Si2O8: Eu2+ doped with different content Sr2+ and Mg2+ ions, were prepared by solid-state reaction at high temperature. And their structure and photo-luminescent properties were investigated. In Ca0.96-ySryAl2Si2O8: 0.04Eu2+ (y = 0.10, 0.30, 0.50, 0.70, 0.90) system, for y ≦ 0.03, all the compositions crystallize in triclinic structure of CaAl2Si2O8, and on further increase of y, the system undergoes a compositionally induced phase transition from triclinic to monoclinic structure. For Ca0.96-yMgyAl2Si2O8: 0.04Eu2+ (y = 0.10, 0.30, 0.50, 0.70, 0.90) system, for z ≦ 0.03, all the compositions are of triclinic structure of CaAl2Si2O8. With the further increase of z, other phase appears. The emission spectra of these phosphors show blue shift with the introduction of Sr2+ ions, and red shift with Mg2+ ions. The reason may be due to the difference ionic radii of Mg2+, Ca2+, Sr2+. These phosphors show excellent blue emission and broad excitation band in near-UV (ultraviolet) range. They may be potential phosphors for near-UV light-emitting diodes (LEDs).

Synthesis and luminescence properties of (Lu0.95−xCe0.05)2Ca1+2xMg2Si3O12 silicate garnet phosphors and its applications

2016 ◽  
Vol 09 (03) ◽  
pp. 1650049
Author(s):  
Wei Xia ◽  
Xiyan Zhang ◽  
Liping Lu
Keyword(s):  
Light Emitting Diode ◽  
Red Light ◽  
Emission Spectra ◽  
Peak Wavelength ◽  
Excitation Peak ◽  
Light Emitting ◽  
White Leds ◽  
Reducing Atmosphere ◽  
Color Rendering ◽  
Silicate Garnet

Silicate garnet phosphors (Lu[Formula: see text]Ce[Formula: see text]Ca[Formula: see text]Mg2Si3O[Formula: see text] with [Formula: see text], 0.05, 0.1, and 0.15 were prepared by high-temperature solid-state reaction in a reducing atmosphere. The crystal structure, photoluminescence and luminescence of the phosphors were investigated. The optimum excitation peak wavelength of the phosphors ranged from 450[Formula: see text]nm to 490[Formula: see text]nm, matching the emission spectra of a blue light-emitting diode chip. The phosphors emit orange-red light after excitation that can be tuned from 589[Formula: see text]nm to 597[Formula: see text]nm by changing the concentration of calcium ions. In addition, their emission made them suitable for use in warm-white LEDs with a high-color rendering index.

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