Encoding of quantum algorithm and devices therefrom are provided. The encoding includes receiving a unitary matrix operator representing the quantum algorithm, each row of the unitary matrix operator defining a superposition of basis state vectors for transforming input states to output states. The encoding also includes recording rows of the unitary matrix operator by applying, to a volume holographic element, a combination of an i.sup.th one of n reference waves and a superposition of n signal waves defined by the superposition defined in an i.sup.th row of the unitary matrix operator. The n signal waves are a first set of n plane waves lying on a first conical surface having a first half angle and the n reference waves are a second set of n plane waves lying on a second conical surface, concentric with the first conical surface, with a second half angle different that the first half angle.