Proceedings Article | 14 February 2007
KEYWORDS: Mirrors, Electronics, Ceramics, Aluminum nitride, Collimation, Diode pumped solid state lasers, Prisms, Optical components, Aluminum, Manufacturing
The forced air Turbo Heat Sink / THS [1], an effective cooler for electronics, handles large flows of air and energy.
AlN, a ceramic, sports low TCE and a good thermal conductivity; the deep, curved air-cooling channels are milled
before firing; later, to suit an automated assembly, precision grinding forms a mounting plane with more linear grooves.
The mounting plane solders directly the Laser Diodes / LD and a full fledged hybrid electronics, while the shallow
grooves, part of a semi-kinematic positioning, locate accurately the coupling optics.
Those AlN THSs are available up to &fgr;⩽300mm. Co-integrating optics with the driving electronics compacts the system.
The on board &mgr;Processor with IOs programs currents and timings, logs temperatures and powers, compensates ageing.
Running much hotter than the LDs, the digital and power dices are better rim mounted.
The planar top of a THS solder mounts a large field of well spaced LDs, bars or single channel; this direct dice assembly
at low density cuts the thermal losses to extend the operating life; at the same time it improves the emitted beams.
Few shared optical elements collimate each beam, moderately elliptical and large as possible.
In front of each row of LDs, a shallow groove seats a long cylindrical lens and a prism; both correct the astigmatism and
bend upward the expanding rays. Above, an array of cylindrical and spherical lenses collimates collectively each
expanding beam. Finally, a large hollow mirror focuses the pumping energy on the lasing rod; its conical or bell shape
uniforms the feed intensity with an optimal, narrow range of incidence angles.
The AlN THS and the grooves position the optical shaping elements on a regular matrix; this radial or parallel order
needs simple methods to assembly few low-cost parts. The output window closes the hermetic chamber.
Adapting the final coupling optics, the same light generating engine can side etc feed a lasing slab.
