Mach-Zehnder-based measurement of light emitting diodes temporal coherence

Torcal-Milla, F. (Universidad de Zaragoza) ; Lobera Salazar, J. (Universidad de Zaragoza) ; Lopez, A. M. (Universidad de Zaragoza) ; Palero, V. (Universidad de Zaragoza) ; Andres Gimeno, N. (Universidad de Zaragoza) ; Arroyo de Grandes, M. P. (Universidad de Zaragoza)

Resumen: Objectives: The main objective of this work is to validate a Mach-Zehnder based interferometric method to measure the temporal coherence length of broadband finite size light sources such as Light Emitting Diodes (LEDs), and give a qualitative value of the temporal coherence length of white LEDs, for which nor their spectral width neither their emission peak wavelength are clearly defined. Motivation: Low-coherence light sources such as LEDs have opened many possibilities in applications in which using lasers introduces coherent noise (speckle) that hinders the performance of interferometric measurement techniques. The coherence length is an important characteristic of light sources for scientific applications related to diffraction, holography, tomography, or interferometry. The spatial coherence of a source depends on the distance from the source to the observation plane and its size, while the temporal coherence is related to the emission spectral width and the emission peak wavelength. Therefore, the temporal coherence is a characteristic of each source. Methodology and results: In this work, we use a Mach-Zehnder interferometer for the first time to measure the coherence degree and the temporal coherence length of quasi-monochromatic LEDs. We validate the technique by comparing the results to those obtained directly from the spectrum. Then, we use the tested interferometric method to measure the temporal coherence length of a white LED, for which neither the width of the spectrum nor the emission peak wavelength, are clearly defined. In this case, the Wiener-Khinchin theorem is used to validate the interferometric technique. A very interesting property of the method is that the temporal coherence length is obtained from a single measurement, without needing to perform a scanning. This method can be used also for other non-coherent sources such as halogen lamps, pulsed lasers, and so on. The obtained results will improve the characterization of light sources and the applications dealing with physical optics and electromagnetic interference. © 2022 The Authors

Idioma: Inglés

DOI: 10.1016/j.ijleo.2022.169722

Año: 2022

Publicado en: Optik 267 (2022), 169722 [11 pp.]
ISSN: 0030-4026

Factor impacto JCR: 3.1 (2022)

Categ. JCR: OPTICS rank: 41 / 99 = 0.414 (2022) - Q2 - T2

Factor impacto CITESCORE: 5.7 - Engineering (Q1) - Physics and Astronomy (Q1) - Materials Science (Q2)

Factor impacto SCIMAGO: 0.539 - Atomic and Molecular Physics, and Optics (Q2) - Electronic, Optical and Magnetic Materials (Q2) - Electrical and Electronic Engineering (Q2)

Financiación: info:eu-repo/grantAgreement/ES/DGA-FEDER/E44-20R
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2020-113303GB-C22
Financiación: info:eu-repo/grantAgreement/ES/UZ/JIUZ-2020-CIE-06

Tipo y forma: Article (Published version)

Área (Departamento): Área Física Aplicada (Dpto. Física Aplicada)
Área (Departamento): Área Teoría Señal y Comunicac. (Dpto. Ingeniería Electrón.Com.)