Temporal coherence properties of laser modules used in headlamps determined by a Michelson interferometer

2020 ◽  
Vol 9 (6) ◽  
pp. 375-383
Author(s):  
Valerie Popp ◽  
Philipp Ansorg ◽  
Burkhard Fleck ◽  
Cornelius Neumann
Keyword(s):  
White Light ◽  
Michelson Interferometer ◽  
Temporal Coherence ◽  
Experimental Setup ◽  
Light Sources ◽  
Coherence Lengths

AbstractIn this work, an investigation of the temporal coherence properties of radiation which is emitted by laser modules integrated in headlamps is presented. The motivation for these measurements was difficulties concerning the field of classification for laser products which function as conventional headlamps. Based on an experimental setup including a Michelson interferometer, a goniophotometer and a spectrometer, coherence lengths of 92.5 and 147.0 μm are obtained for two different laser modules. The results show that the temporal coherence of the examined radiation is appreciably higher than the temporal coherence of conventionally produced white light. Therefore, at this point in time, laser modules used in headlamps cannot be considered as customary white light sources.

Direct Measurement of Coherence Lengths and Analysis of Spectra of Light Sources by Using a Michelson Interferometer

2013 ◽  
Vol 63 (6) ◽  
pp. 638-642
Author(s):  
Choong Hwan LEE ◽  
Hee Joo CHOI ◽  
Byoung Joo KIM ◽  
Myoungsik CHA*
Keyword(s):  
Direct Measurement ◽  
Michelson Interferometer ◽  
Light Sources ◽  
Coherence Lengths

Polariton Devices

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Semiconductor Devices ◽  
Logic Gates ◽  
Light Sources ◽  
Coherent Light ◽  
Final State ◽  
Spintronic Devices ◽  
Exciton Polaritons ◽  
Terahertz Lasers ◽  
Coherence Lengths ◽  
Stimulation Of

Polariton devices offer multiple advantages compared to conventional semiconductor devices. The bosonic nature of exciton polaritons offers opportunity of realisation of polariton lasers: coherent light sources based on bosonic condensates of polaritons. The final state stimulation of any transition feeding a polariton condensate has been used in many proposals such as for terahertz lasers based on polariton lasers. Furthermore, large coherence lengths of exciton-polaritons in microcavities open the way to realisation of polariton transport devices including transistors and logic gates. Being bosonic spin carriers, exciton-polaritons may be used in spintronic devices and polarisation switches. This chapter offers an overview on the existing proposals for polariton devices.

Crystalline Silicon White Light Sources Driven by Optical Resonances

Nano Letters ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2397-2405
Author(s):  
Jin Xiang ◽  
Mincheng Panmai ◽  
Shuwen Bai ◽  
Yuhao Ren ◽  
Guang-Can Li ◽  
...  
Keyword(s):  
White Light ◽  
Crystalline Silicon ◽  
Light Sources ◽  
Optical Resonances

scholarly journals An Efficient Method for LED Light Sources Characterization

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1089 ◽  
Author(s):  
Sara Raggiunto ◽  
Alberto Belli ◽  
Lorenzo Palma ◽  
Piergiovanni Ceregioli ◽  
Massimo Gattari ◽  
...  
Keyword(s):  
Efficient Method ◽  
Least Squares Method ◽  
Color Temperature ◽  
Experimental Setup ◽  
Light Sources ◽  
Careful Study ◽  
Source Characterization ◽  
Led Light ◽  
Lighting Systems ◽  
Led Drivers

Digital LED drivers capable of blending the spectrum of two LED fixtures with different Correlated Color Temperatures through the LEDs’ power supply control are widespread. However, the digital control of lighting systems is possible only after a careful study of the LED’s response, in terms of illuminance and Correlated Color Temperature. The proposed work takes advantage of the Tunable White technology for the realization of an efficient method for LED light source characterization. In order to evaluate how the light changes as a function of the electric power supplied by the LED drivers, an experimental setup to characterize LED light sources has been designed. Starting from the data acquired from the experimental setup, a model for dimming the LED driver and obtaining the desired values of quality of light has been developed. The proposed model is based on the least squares method and its accuracy is evaluated by comparing the obtained values of illuminance and Correlated Color Temperature with those measured by an illuminance spectrophotometer. Results achieved an error of 0.3% for Correlated Color Temperature and 1.5% for illuminance using the proposed approximation functions.

scholarly journals Photocatalytic Performance of ZnO: Al Films under Different Light Sources

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Prashant Pradhan ◽  
Juan Carlos Alonso ◽  
Monserrat Bizarro
Keyword(s):  
White Light ◽  
Irradiation Time ◽  
Zno Films ◽  
Light Sources ◽  
X Ray Diffraction ◽  
Treatment Processes ◽  
Vis Spectroscopy ◽  
Doped Zno ◽  
Very High ◽  
High Degradation Rate

ZnO and Al doped ZnO films were produced by spray pyrolysis. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectroscopy, and photoluminescence. Their photocatalytic activity was evaluated by the decomposition of the methyl orange dye using different light sources: ultraviolet light, artificial white light, and direct sunlight. The films were also tested under darkness for comparison. The ZnO films were able to degrade the test pollutant under UV and sunlight in more than a 60% after 180 min of irradiation and a scarce degradation was obtained using white light. However, the Al doped ZnO films presented a very high degradation rate not only under UV and sunlight (100% degradation), but also under white light (90% degradation after the same irradiation time). An unexpected high degradation was also obtained in the dark, which indicates that a nonphotonic process is taking place parallel to the photocatalytic process. This can be due to the extra electrons—provided by the aluminum atoms—that migrate to the surface and produce radicals favoring the decomposition process even in the dark. The high activity achieved by the ZnO: Al films under natural conditions can be potentially applied to water treatment processes.

scholarly journals System efficiency of laser-based white light

2014 ◽  
Vol 3 (5-6) ◽  
Author(s):  
Roland Lachmayer ◽  
Alexander Wolf ◽  
Gerolf Kloppenburg
Keyword(s):  
Thermal Management ◽  
White Light ◽  
High Power ◽  
Laser Diodes ◽  
Light Sources ◽  
System Efficiency ◽  
Light Emitting ◽  
Scale Down ◽  
Color Rendering ◽  
Product Weight

AbstractFor many lighting applications, light-emitting diodes (LEDs) are replacing traditional light sources providing the possibility for smart and efficient systems as well as a reduction in the product weight. A next step in this development is the integration of laser-based light sources to increase luminance and to further scale down the optics possibly leading to a reduction of necessary resources. This article reviews the possibilities and challenges arising from the use of laser diodes especially compared to current high-power LED systems in terms of efficiency, color-rendering properties, and thermal management.

>25 Gbit/s LiFi with Dual Wavelength Emission, Eye-safe, Laser Based White Light Collimated and Fiber Delivered Light Sources

2021 ◽  
Author(s):  
James Raring ◽  
Changmin Lee ◽  
Mohamed Sufyan Islim ◽  
Sovan Das ◽  
Adrian Sparks ◽  
...  
Keyword(s):  
White Light ◽  
Dual Wavelength ◽  
Light Sources ◽  
Wavelength Emission

Prospects for 4-laser white-light sources

2018 ◽  
Vol 66 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Snjezana Soltic ◽  
Andrew N. Chalmers
Keyword(s):  
White Light ◽  
Light Sources

scholarly journals Nanophosphors-Based White Light Sources

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1048 ◽  
Author(s):  
Maura Cesaria ◽  
Baldassare Di Bartolo
Keyword(s):  
Rare Earth ◽  
White Light ◽  
Volume Ratio ◽  
Light Sources ◽  
Co Doping ◽  
New Class ◽  
Luminescence Efficiency ◽  
Metal Doped ◽  
The Individual ◽  
The Impact

Miniaturization requests and progress in nanofabrication are prompting worldwide interest in nanophosphors as white-emission mercury-free lighting sources. By comparison with their bulk counterparts, nanophosphors exhibit reduced concentration quenching effects and a great potential to enhance luminescence efficiency and tunability. In this paper, the physics of the nanophoshors is overviewed with a focus on the impact of spatial confinement and surface-to-volume ratio on the luminescence issue, as well as rare earth-activated multicolor emission for white light (WL) output. In this respect, the prominently practiced strategies to achieve WL emission are single nanophosphors directly yielding WL by means of co-doping and superposition of the individual red, green, and blue emissions from different nanophosphors. Recently, a new class of efficient broadband WL emitting nanophosphors has been proposed, i.e., nominally un-doped rare earth free oxide (yttrium oxide, Y2O3) nanopowders and Cr transition metal-doped garnet nanocrystals. In regard to this unconventional WL emission, the main points are: it is strictly a nanoscale phenomenon, the presence of an emitting center may favor WL emission without being necessary for observing it, and, its inherent origin is still unknown. A comparison between such an unconventional WL emission and the existing literature is presented to point out its novelty and superior lighting performances.

scholarly journals Luminous Efficacy of LED White Light Sources

2016 ◽  
Vol 16 (06) ◽  
pp. 64-74
Author(s):  
V Pavlov ◽  
V Pyasetskiy ◽  
A Horohorov ◽  
A Shirankov
Keyword(s):  
White Light ◽  
Light Sources ◽  
Luminous Efficacy
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