April 2011
Spotlight Summary by Aliaksandr Kachynski
465 nm laser sources by intracavity frequency doubling using a 49-edge-emitters laser bar
Furthermore, they offer extremely high contrasts and, owing to their operating principle, they are always in focus on any kind of surface. In addition to their optical performance, prospective laser projection systems are believed to be less power consuming and more compact than comparable conventional display technologies. Because of the enormous potential of the consumer markets, there is a significant interest for development of compact, inexpensive, and highly efficient laser sources in the visible spectral range.
The authors of this paper in Optics Letters are actively moving in the direction of engineering of high-brightness compact lasers, integrating an international team, as well as technical advances of modern photonic technologies. In most cases, conventional SSL in the visible range are based on the intracavity doubling of the radiation of IR lasers pumped by laser diode (LD)modules. Efficient wavelength conversion of the emission of the LDs themselves, instead of intermediate pumping of the IR active media in SSL, is a significant technological step toward laser cost reduction and increasing slope efficiency. The authors successfully explored this concept, first for the green laser with 534.7 nm, reported in a previous publication and now for a highly efficient blue laser, operating at an output power of 1.2 W at 465 nm.
In both lasers, with green and blue outputs, the advanced technique of intracavity doubling of the IR radiation of 49 single-mode edge-emitters diode bar was used. MgO-doped periodically poled lithium niobate (MgO:PPLN) bulk crystal with unique optical properties assured high-efficient second-harmonic generation (SHG). Adding 5% magnesium-oxide to lithium niobate significantly increases the optical and the photorefractive resistance of the crystal while preserving its high nonlinear coefficient.
Compact packaging design (~16 cm3), low radiation noise (~4%), and stable laser operation (power fluctuation ?4%) of the direct LD-SHG converted blue laser configuration presented in this work make this technology promising and efficient for further engineering of the laser projection system technology.
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Article Information
465 nm laser sources by intracavity frequency doubling using a 49-edge-emitters laser bar
K. Li, H. Wang, N. J. Copner, C. B. E. Gawith, I. G. Knight, H.-U. Pfeiffer, B. Musk, and G. Moss
Opt. Lett. 36(3) 361-363 (2011) View: Abstract | HTML | PDF