Achievement of ultrahigh solar concentration with potential for efficient laser pumping

Area of Science:

• Optical Engineering
• Renewable Energy Technologies
• Thermodynamics

Background:

• Solar concentrators are crucial for high-flux solar energy applications.
• Achieving thermodynamic limits in solar concentration is a key research goal.
• Previous solar irradiance records limit the efficiency of solar energy conversion.

Purpose of the Study:

• To measure the irradiance produced by a novel two-stage solar concentrator.
• To evaluate the concentrator's performance relative to the thermodynamic limit.
• To assess the system's potential for solar-powered solid-state lasers.

Main Methods:

• Utilized a two-stage design with a parabolic primary and a nonimaging refracting secondary.
• Employed a 40.6-cm diameter primary mirror and a 1.53 refractive index secondary.
• Measured final irradiance at a 1.27 mm diameter aperture with a geometrical concentration ratio of 102,000.

Main Results:

• Achieved a peak irradiance of 4.4 +/- 0.2 kW cm(-2), equivalent to 56,000 +/- 5000 suns.
• This represents a nearly threefold increase over previous solar irradiance records.
• The achieved irradiance is 68% of the solar surface irradiance.

Conclusions:

• The two-stage solar concentrator approaches the thermodynamic limit for irradiance.
• The system's high efficiency in concentrating sunlight is promising.
• The concentrator is a strong candidate for solar pumping of solid-state lasers.