Laser aperture integrated with position-sensing detectors

A laser alignment aperture for automation of laser beam alignment has been realized. The expected system application is to define a straight line by placing apertures integrated with position sensitive photodiodes in the beam path. Any deviation of the incident laser beam from the predetermined path causes it to strike one of the four photodiode quadrants around one of the apertures. The photocurrent signal produced at one of the four detector quadrants, when compared to the photocurrents from the other quadrants provides a measurement of the beam position. Using standard silicon microfabrication and micromachining processes, apertures from 0.5 to 1.3 mm diameter have been fabricated.