High-pass filtering in coaxial holographic data storage

To reduce the loss of the dynamic range M/# of medium, we have proposed and demonstrated a high-pass filtering method for coaxial holographic data storage. Total exposure power decreased to 1/2 by removing the DC components of the Fourier-transformed signal and reference beams with a high-pass filter. Our proposed method can reduce the wasted dynamic range of medium. We evaluated the bit error rate of a high-pass-filtered signal beam to be 5.0 x 10(-4) and that of an unfiltered signal beam to be 1.3 x 10(-3). Thus, we confirmed that the quality of the signal beams without the DC component is comparable to that with the DC component. Next, we successfully recorded and reconstructed the filtered signal beam with the coaxial holographic configuration. The bit error rate of the retrieved signal beam was 1.4 x 10(-3), showing the absence of degradation without the DC component of the retrieved signal beam. We also evaluated the shift selectivity improved from 5 to 2 mu m by high-pass filtering.