Summary from only given. We have devised a novel method to improve the diffraction efficiencies of holograms to a theoretical maximum of up to 100%. This is accomplished by placing the hologram inside a resonant optical cavity. Resonance ensures that the diffracted beams add up constructively while reflected beams at the entrance of the optical cavity are eliminated. The recording procedure takes place outside the cavity and is done by conventional means. We present a schematic of the resonant holographic geometry with normal incidence. VHOE denotes the volume holographic optical element and PRM the partially reflecting mirror.