Solid-state source of intense yellow light based on a Ce:YAG luminescent concentrator

• Published in: Optics express Vol. 25; no. 12; pp. 13714 - 13727
• Main Authors: Sathian, Juna, Breeze, Jonathan D, Richards, Benjamin, Alford, Neil McN, Oxborrow, Mark
• Format: Journal Article
• Language: English
• Published: United States 12.06.2017
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.25.013714

A luminescent concentrator functioning as a bright source of yellow light is reported. It comprises a waveguide made of cerium-doped YAG crystal, in the form of a long-thin rectangular strip, surrounded by flowing air and optically pumped from both sides with blue light from arrays of high-efficiency InGaN LEDs. Phosphor-converted yellow light, generated within the strip, is guided to a glass taper that is butt-coupled to one of the strip's end faces. Up to 20 W of optical power, centered on 575 nm with a linewidth of 76 nm, can be continuously radiated into air from the taper's 1.67 mm × 1.67 mm square output aperture. The intensity of the outputted light is significantly greater than what any yellow (AlGaInP) LED can directly produce (either singly or arrayed), with only a modest increase in linewidth. Furthermore, the wall-plug efficiency of the source exceeds that of any yellow laser. The concept allows for further substantial increases in intensity, total output power and wall-plug efficiency through scaling-up and engineering refinements.