Efficient 750-nm LED-pumped Nd:YAG laser.

Area of Science:

• Laser Physics
• Solid-State Lasers
• Optoelectronics

Background:

• Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) lasers are widely used.
• Traditional pumping methods often involve complex or inefficient sources.
• Developing efficient and compact pumping schemes is crucial for advancing laser technology.

Purpose of the Study:

• To investigate the feasibility and performance of an Nd:YAG laser pumped by light-emitting diodes (LEDs).
• To evaluate the laser's output energy, efficiency, and beam quality under different cavity configurations.
• To explore an alternative, potentially more accessible pumping source for Nd:YAG lasers.

Main Methods:

• An Nd:YAG crystal was pumped using 750 nm LEDs with a 1-ms pulse duration at a 10 Hz repetition rate.
• Two cavity designs were tested: a linear cavity and a Z-cavity.
• Output coupling varied between 1% and 5% to optimize performance.
• Laser output energy, optical efficiency, slope efficiency, and beam quality (M² factor) were measured.

Main Results:

• In a linear cavity with 1% output coupling, the laser produced 37.5 μJ pulse energy (1064 nm) with M² = 1.1, achieving 1.36% optical and 9% slope efficiency.
• In a Z-cavity, pulse energies of 346 μJ (1% output coupling) and 288 μJ (5% output coupling) were achieved.
• The Z-cavity demonstrated higher optical efficiencies (3.4% and 2.8%) and a peak slope efficiency of 14% (5% output coupling).
• The M² factor for the Z-cavity's highest output was measured at 3.6.

Conclusions:

• LED pumping is a viable method for exciting Nd:YAG lasers.
• The Z-cavity configuration offers significantly higher pulse energy and efficiency compared to the linear cavity.
• Further optimization of LED-pumped Nd:YAG lasers could lead to compact and efficient laser sources.