Barrier-grid membrane light modulator

An electron-beam membrane light modulator (EBMLM) for use in real-time holographic imaging has recently been constructed. This particular EBMLM is built as a barrier-grid storage tube. The target is the polymer membrane itself upon which Js deposited a 100 × 100 array of metallized islands. A charge pattern corresponding to the video holographic signal is written on the metallized islands. Corresponding electrostatic forces exerted upon the islands cause the membrane to deflect locally, thus spatially phase-modulating coherent light reflecting from the opposite side. Because of the low capacitance of each island (0.01 pF, typically) and their small size (10-40 µm) it should be possible to perform real-time holographic imaging with arrays consisting of 1 million elements at full video bandwidths. Design trade-offs are discussed.