Laser Power Transmission Employing a Dual-Use Photovoltaic Concentrator at the Receiving End

The proposed innovation is a wireless laser power transmission system employing a dual-use photovoltaic concentrator at the receiving end. Specifically, the laser receiver/converter employs thin Fresnel lenses to focus continuous or pulsed laser light onto small photovoltaic cells, thereby reducing cell cost and improving cell conversion efficiency (> 70% near term). The dual-use approach employs a novel four-terminal multijunction cell interconnection design to allow the same photovoltaic concentrator to be used as a state-of-the-art solar array. Specifically, the photovoltaic concentrator uses multijunction cells for the high-efficiency solar radiation conversion (> 30% near-term), but only the top junction of such cells for the high-efficiency laser radiation conversion. After system optimization in Phase I and system demonstration in Phase II, the new modular laser/solar photovoltaic concentrator will have many NASA, military, and commercial space applications. Applications include spacecraft arrays receiving laser input from other spacecraft or from Earth; lunar or planetary arrays receiving laser input from nearby spacecraft or from Earth; and Earth-based arrays receiving laser input from space solar power (SSP) spacecraft. The dual-use capability enables state-of-the-art solar power operation when sunlight is available (e.g., illuminated orbit portion), and laser operation when sunlight is not available (e.g., eclipse orbit portion).