High Efficiency 808-nm VCSEL Arrays with Excellent Beam Quality Navy SBIR FY2012.2 Sol No.: Navy SBIR FY2012.2 Topic No.: N122-112 Topic Title: High Efficiency 808-nm VCSEL Arrays with Excellent Beam Quality Proposal No.: N122-112-1033 Firm: nLight Photonics 5408 NE 88th Street, Bldg E Vancouver, Washington 98665 Contact: Zhigang Chen Phone: (360) 566-4460 Web Site: www.nlight.net Abstract: Today's high energy Q-switched Nd:YAG lasers are often pumped by stacks of multiple edge-emitting diode laser bars since the vertical-cavity surface-emitting laser (VCSEL) traditionally have been lower in efficiency. In this effort we are proposing a novel VCSEL design which overcomes the efficiency bottleneck in conventional VCSEL while preserving its beneficial attributes such as uniform beam in the far-field, higher brightness, narrow spectral width, less sensitivity to thermal drift in center wavelength and lower cost of manufacturing. Under the proposed program, nLight will develop and demonstrate a high power, high efficiency and high beam quality VCSEL array near 808 nm, with efficiency compared to the state-of-the-art edge-emitting diode laser bars. nLight will achieve this by leveraging its industry-leading high efficiency 808-nm epitaxy design, and incorporating a cascaded bipolar VCSEL design. The end goal of the program is to achieve > 60% wallplug efficiency and >1 kW QCW optical power in a 0.5 cm2 high power VCSEL array, with a spectral width less than 1 nm and a temperature coefficient of lower than 0.1 nm/�C. Benefits: The high efficiency and high power 808-nm VCSEL arrays herein is principally motivated by pumping Q-switched Nd:YAG lasers for many military, industrial, and medical applications. We expect to implement these into our military handheld rangefinder and marker products. Currently, nLight makes rangefinder for STORM and this can serve as a next generation pump source for wide operating temperature range. Furthermore, the VCSEL array to be developed will ultimately lead to smaller, lighter, and less complex laser systems suitable for mobile platforms such as UAV's. nLight has a good track record of commercializing the results of DoD-funded research, and expects to commercialize devices developed under this program as rapidly as possible. Manufacturability has been considered from the bottom up in the approach proposed herein. There is also a growing commercial market for materials processing where high power at low cost is the key to breaking into this market and enabling the applications where light is used instead of heat for surface modifications and low temperature welding. Return