Dual Wavelength White LED for Performance Improvement of White Light Interferometry

2013 ◽  
Author(s):  
Wee Keat CHONG ◽  
Xiang LI ◽  
Yeng Chai SOH
Keyword(s):  
Performance Improvement ◽  
White Light ◽  
Dual Wavelength ◽  
White Led ◽  
White Light Interferometry

Improved Yellow Light Emission in the Achievement of Dichromatic White Light Emitting Diodes

2013 ◽  
Vol 1538 ◽  
pp. 371-375
Author(s):  
Zhao Si ◽  
Tongbo Wei ◽  
Jun Ma ◽  
Ning Zhang ◽  
Zhe Liu ◽  
...  
Keyword(s):  
Blue Light ◽  
White Light ◽  
Light Emitting Diodes ◽  
Light Emission ◽  
Dual Wavelength ◽  
Emission Wavelength ◽  
White Led ◽  
Yellow Light ◽  
Light Emitting ◽  
White Light Emitting Diodes

ABSTRACTA study about the achievement of dichromatic white light-emitting diodes (LEDs) was performed. A series of dual wavelength LEDs with different last quantum-well (LQW) structure were fabricated. The bottom seven blue light QWs (close to n-GaN layer) of the four samples were the same. The LQW of sample A was 3 nm, and that of sample B, C and D were 6 nm, a special high In content ultra-thin layer was inserted in the middle of the LQW of sample C and on top of that of sample D. XRD results showed In concentration fluctuation and good interface quality of the four samples. PL measurements showed dual wavelength emitting, the blue light peak position of the four samples were almost the same, sample A with a narrower LQW showed an emission wavelength much shorter than that of sample B, C, D. EL measurement was done at an injection current of 100 mA. Sample A only showed LQW emission due to holes distribution. Because of wider LQW, the emission wavelength of sample B, C and D was longer and peak intensity was weaker. Sample D with insert layer on top of LQW showed strongest yellow light emission with a blue peak. As the injection current increased, sample A showed highest output light power due to narrower LQW. Of the other three samples with wider LQW, sample D showed highest output power. Effective yellow light emission has always been an obstacle to the achievement of dichromatic white LED. Sample D with insert layer close to p-GaN can confine the hole distribution more effectively hence the recombination of holes and electrons was enhanced, the yellow light emission was improved and dichromatic white LED was achieved.

Fringe order identification in optical fibre white-light interferometry using centroid algorithm method

1992 ◽  
Vol 28 (6) ◽  
pp. 553 ◽  
Author(s):  
S. Chen ◽  
A.W. Palmer ◽  
K.T.V. Grattan ◽  
B.T. Meggitt
Keyword(s):  
Optical Fibre ◽  
White Light ◽  
White Light Interferometry ◽  
Fringe Order ◽  
Centroid Algorithm

scholarly journals Integrated, Speckle-Based Displacement Measurement for Lateral Scanning White Light Interferometry

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2486
Author(s):  
Gert Behrends ◽  
Dirk Stöbener ◽  
Andreas Fischer
Keyword(s):  
White Light ◽  
Lateral Displacement ◽  
Displacement Measurement ◽  
Accurate Information ◽  
White Light Interferometry ◽  
Fully Integrated ◽  
Speckle Correlation ◽  
Dsc Measurements ◽  
Scanning White Light Interferometry ◽  
The Impact

Lateral scanning white light interferometry (LSWLI) is a promising technique for high-resolution topography measurements on moving surfaces. To achieve resolutions typically associated with white light interferometry, accurate information on the lateral displacement of the measured surface is essential. Since the uncertainty requirement for a respective displacement measurement is currently not known, Monte Carlo simulations of LSWLI measurements are carried out at first to assess the impact of the displacement uncertainty on the topography measurement. The simulation shows that the uncertainty of the displacement measurement has a larger influence on the total height uncertainty than the uncertainty of the displacing motion itself. Secondly, a sufficiently precise displacement measurement by means of digital speckle correlation (DSC) is proposed that is fully integrated into the field of view of the interferometer. In contrast to externally applied displacement measurement systems, the integrated combination of DSC with LSWLI needs no synchronization and calibration, and it is applicable for translatory as well as rotatory scans. To demonstrate the findings, an LSWLI setup with integrated DSC measurements is realized and tested on a rotating cylindrical object with a surface made of a linear encoder strip.

Polarization insensitive fibre-optic white-light interferometry

1995 ◽  
Vol 114 (5-6) ◽  
pp. 386-392 ◽  
Author(s):  
L.A Ferreira ◽  
J.L Santos ◽  
F Farahi
Keyword(s):  
White Light ◽  
Fibre Optic ◽  
White Light Interferometry ◽  
Polarization Insensitive

Fiber-optic white-light interferometry: lead sensitivity considerations

1994 ◽  
Vol 19 (2) ◽  
pp. 138 ◽  
Author(s):  
R. R. Gauthier ◽  
N. Dahi ◽  
F. Farahi
Keyword(s):  
White Light ◽  
Fiber Optic ◽  
White Light Interferometry

A White-Light Interferometry for the Measurement of High-Finesse Fiber Optic EFPI Sensors

2014 ◽  
Vol 26 (21) ◽  
pp. 2138-2141 ◽  
Author(s):  
Zhen Wang ◽  
Yi Jiang ◽  
Wenhui Ding ◽  
Ran Gao
Keyword(s):  
White Light ◽  
Fiber Optic ◽  
White Light Interferometry ◽  
High Finesse

Improved synthesised source for white light interferometry

1994 ◽  
Vol 30 (17) ◽  
pp. 1440-1441 ◽  
Author(s):  
Y.J. Rao ◽  
D.A. Jackson
Keyword(s):  
White Light ◽  
White Light Interferometry

Fiber optic white-light interferometry for self-calibrated absolute-strain measurements

1996 ◽  
Author(s):  
Vikram Bhatia ◽  
Kent A. Murphy ◽  
Richard O. Claus ◽  
Tuan A. Tran ◽  
Jonathan A. Greene
Keyword(s):  
White Light ◽  
Fiber Optic ◽  
White Light Interferometry ◽  
Strain Measurements
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