[Laser] laser optics questions

[Charles Pooley]

Clint:

The single most outstanding feature of the usual edge emitting laser diodes (not VCSEL which are axisymmetric) the 2 orthoganol directions of the light are evvectively at 2 different distances from the face, and the widely spreading direction is because of the narrow emitting width.

With a cylindrical lense or that feature ground into a lense, the 2 locations can be both brought into focus, then the light acts as though coming from a small point, and conventionaql optics can expand the beam diameter then render it parallel with another larger lense of telescope mirror. 

I plan this for the space data link for Microlaunchers as seen in a short sample of the math:
(  http://www.microlaunchers.com/7816/L3/laser/laser-link.html ).

If a separate cylinder lense is used, it can be focussed separately so the beam is axially symetrical, then, with conventional optics--a small lense and a thin parabolic mirror, focussed ot a diffraction limited 2 arc seconds or so.

This can be done on the ground, indoors or inside a straight length of pipe.  2" would be a focussed spot 100 micron diameter per 10 m of setup lengh.

VCSEL is one of the cheaper laser types, but most are limited to about 1.5 mw and 850 nm wavelength.

Cheap optics?  Orion has the $49.95 "FunScope"  76 mm Newtonian.  Has spherical mirror, but $49.95:

  http://www.telescope.com/control/telescopes/mini-dobsonian-telescopes/funscope-76mm-reflector-telescope

    Charles Pooley     KD6HKU               
    ckpooley at sbcglobal.net
    http://www.microlaunchers.com/