Study of self-interference incoherent digital holography for the application of retinal imaging

Adaptive optics (AO) using digital holography (DH) is more effective in terms of complexity and cost than other AO techniques. However, use of coherent illumination is problematic in applying DHAO for retinal imaging because of speckle noise. Self-interference incoherent digital holography (SIDH) is a technique to record holographic information from the object illuminated by incoherent light. By adopting SIDH for the full-field imaging, the speckle noise problem can be avoided with incoherent illumination. However, the guide-star hologram for AO requires the guide-star to be smaller than retinal cell size to achieve sufficient resolution. Hence, the proposed SIDH AO system is configured with a hybrid illumination system which uses incoherent illumination for recording of full-field hologram while laser is used for guide-star hologram. Preliminary experiment using an array of micro-spheres for the object shows that the full-field hologram and guide-star hologram can be recorded by proposed optical configuration.