an apodization system for achieving a substantially uniform intensity profile of a modulated reference beam on a holographic recording medium is disclosed . the substantially uniform intensity profile serves to improve the quality of any and all recorded holograms . in high - density holographic storage , the apodization system reduces the required hologram extent while still maintaining any fidelity constraints . furthermore , in high - fidelity holographic storage , better control of the hologram recording parameters can be established . the improved control allows tighter specifications on the image quality to be achieved .