Abstract: An apparatus and a method for precisely controlling long-pulse beam intensity in a laser device having a gain medium and a Q-switch disposed in a resonant cavity, and having a pump for supplying constant pulses of energy to the gain medium. The apparatus provides a Q-switch controller for adjustably controlling a timing window during which the Q-switch is open, to define the amount of pump energy coupled into the long pulses, and consequently the intensity of the beam. The controller has an input device for entering a desired length of the timing window, and a display device for displaying an indication of the length.

Abstract: A low coupling beam splitter with no cross-polarization error or critical alignment tolerances is formed of a quartz piece having a first planar face in the optical path in the plane of the cross-polarization and at or near Brewster's angle to the beam. A second planar face is in the interior optical path in the plane of the cross-polarization and off of Brewster's angle to the beam, so that a majority of the component having the dominant polarization is transmitted along the optical path, while a small fraction of the component having the dominant polarization and a portion of the cross-polarized component are reflected along a first interior sample path. A third planar face is in the first interior sample path in the plane of the dominant polarization and at or near Brewster's angle to the reflected beam. Thus, a portion of the component having the dominant polarization is reflected as a sample beam, and the majority of the component having the cross-polarization is transmitted away from the sample beam.