Rod-shaped LuAG:Ce transparent ceramic enabling ultrahigh forward efficiency for laser lighting in a transmissive...

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Lighting

Background:

• Ceramic phosphors offer high thermal conductivity and stability for laser lighting.
• Transmissive mode laser lighting faces challenges with light loss and arbitrary emission from phosphors.

Purpose of the Study:

• To design an effective rod-shaped cerium-doped lutetium aluminum garnet (LuAG:Ce) transparent ceramic for enhanced laser lighting.
• To improve the forward luminous efficiency and thermal management in transmissive mode laser lighting.

Main Methods:

• Fabrication of rod-shaped LuAG:Ce transparent ceramics.
• Silicone encapsulation of ceramic-based devices.
• Testing under laser excitation to evaluate luminous efficiency and thermal stability.

Main Results:

• Achieved stable operation under 3.5 W laser excitation with a luminous efficiency of 150-180 lm/W.
• Demonstrated high power density tolerance (46 W/mm²) without luminous saturation due to gradual blue light absorption and heat distribution.
• Observed minimal thermal-induced luminous degradation (7%) after 15 minutes of operation.
• Obtained laser lighting sources with low divergence angle (∼4°) and uniform spatial distribution.

Conclusions:

• The proposed rod-shaped LuAG:Ce transparent ceramic design significantly enhances forward luminous efficiency in transmissive mode laser lighting.
• The optimized design and encapsulation scheme provide a viable solution for high-power, efficient, and stable ceramic-based laser lighting.
• This work offers a pathway to overcome limitations in current transmissive mode laser lighting technologies.