Laser exposure head with reduced leakage

A laser exposure system, comprising:

• an electro-optic substrate including an electrically-controlled diffraction grating having a controllable state;
• a laser source directing an incident light beam into the electro-optic substrate, wherein when the electrically-controlled diffraction grating is controlled to be in a first state the incident light beam passes through the electro-optic substrate without diffraction providing an undiffracted light beam, and wherein when the electrically-controlled diffraction grating is controlled to be in a second state the incident light beam is diffracted into a plurality of light beams corresponding to different diffraction orders, the plurality of light beams including a zero-order light beam corresponding to a zero diffraction order, and first and second diffracted light beams corresponding to diffraction orders of −n and +n;
• an aperture structure including first and second apertures positioned such that the first diffracted light beam passes through the first aperture and the second diffracted light beam passes through the second aperture, wherein the aperture plate blocks the undiffracted light beam when the electrically-controlled diffraction grating is in the first state and blocks the zero-order light beam when the electrically-controlled diffraction grating is in the second state;
• a polarization rotator which rotates a polarization state of the second diffracted light beam to provide a polarization-rotated second diffracted light beam;
• a polarization beam combiner which combines the first diffracted light beam and the polarization-rotated second diffracted light beam onto a common path forming a combined light beam;
• a print lens which focuses the combined light beam onto an imaging medium;
• and
• a controller which controls the state of the electrically-controlled diffraction grating in accordance with pixel data.