Question

I need to test the resolution of a laser diode imaging system. According to modeling, the resolution is 4.4 micrometers. I need to test the resolution, however, I must maintain the 10 degree divergence angle and no emitters exist with a emitting area less than 4.4 micrometers and a divergence angle of 10 degrees. A pinhole or slit will cause diffraction changing the divergence angle.

Ideas?