Nitrides Seminar - Dr. Guillaume Lheureux, Postdoctoral Researcher

3/16/2017 12PM ESB 1001

Abstract: According to the US Department of Energy, solid-state lighting (SSL) technology could

reduce by 75% the US lighting energy consumption by the end of 2035. The last ten years have

seen impressive progress in light emitting diode (LED) technologies. State of the art single-chip

white light LEDs can now deliver more than 600 lumens (equivalent to a 60 W bulb) with an

efficiency close to 150 lumens per watt (lm/W). However, the decrease in efficiency (droop)

observed when LEDs are driven at high current will be a strong limitation of the LED utilization

in applications where high flux and small dimensions are required.


In order to overcome this limit, we develop here at UCSB a laser-based white light emitter with

no efficiency droop at high current densities and optical and light conversion efficiencies nearing

the maximum intrinsic limits. This approach targets both key metrics for energy-efficiency in

lighting systems for commercial and industrial buildings by addressing the fundamental

performance limitations of LED-based systems operating at high current densities and the cost

limitations of LED systems operating at low drive currents (large chip area) through the use of a

much smaller, single-chip, nearly-idealized point source of emission. The ultimate goal of the

proposed project is the development of a 1000 lm laser-based white emitter with an efficiency of

at least 200 lm/W and a cost of $0.25/klm.During this seminar, we will discuss our latest

experimental and theoretical results. An overview of optical and thermal simulation methods for

solid-state lighting devices will be presented. The laser and phosphor compound will be described

separately as well as their coupling in a device.