Phosphor material dependent spot size limitations in laser lighting.

Anastasiia Krasnoshchoka,Xu Jian,Paul Michael Petersen,Ole Bjarlin Jensen,Dominik Marti,Anders Thorseth,Anders Kragh Hansen

doi:10.1364/oe.383866

Anastasiia Krasnoshchoka, Xu Jian + Show 5 more

Open Access

https://doi.org/10.1364/oe.383866

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Abstract

In laser lighting, a major benefit over other lighting techniques is the possibility to achieve very high luminous exitance. Focusing the exciting laser to a very small spot size on the phosphor, however, does not necessarily provide a very small emitting area for the white light. In this study we investigate experimentally and numerically the relationship between the white light spot size and the incident blue laser spot size. We show that the specific phosphor material properties have significant impact on this relationship and on the achievable minimum spot size. This constitutes a limitation on the minimum spot size achievable in laser lighting and has important implications in applications.

Highlights

Solid-state lighting based on LEDs provides high efficiency and good colorimetric properties and has replaced incandescent light in most applications
We find that the luminescent spot size depends strongly on the phosphor material properties and depends almost linearly on the input blue laser spot size
We have investigated one of the major benefits of laser lighting over other light sources, namely the possibility to achieve a high luminous output from a small area resulting in high luminous exitance

Summary

Introduction

Solid-state lighting based on LEDs provides high efficiency and good colorimetric properties and has replaced incandescent light in most applications. Phosphor converted laser lighting is becoming a competitive alternative to other solid-state lighting technologies based on LEDs [1,2]. Many studies have focused on investigating colorimetric properties and luminescence saturation in phosphors due to the high incident power density [3,4,5,6,7,8]. Few studies have investigated the light distribution from the phosphor converted laser lighting and mainly with the focus of simulating the heat distribution in the phosphor materials [9,10,11,12]

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