  We develop a scheme for time-frequency encoded continuous-variable
cluster-state quantum computing using quantum memories. In particular, we
propose a method to produce, manipulate and measure 2D cluster states in a
single spatial mode by exploiting the intrinsic time-frequency selectivity of
Raman quantum memories. Time-frequency encoding enables the scheme to be
extremely compact, requiring a number of memories that is a linear function of
only the number of different frequencies in which the computational state is
encoded, independent of its temporal duration. We therefore show that quantum
memories can be a powerful component for scalable photonic quantum information
processing architectures.
