nLight Photonics — Department of Defense SBIR Phase I: Today"s high energy Q-switched Nd:YAG lasers are often pumped by stacks of multiple e

Description

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.