  Demand for lightweight, highly reflective and mechanically compliant mirrors
for optics experiments has seen a significant surge. In this aspect, photonic
crystal (PhC) membranes are ideal alternatives to conventional mirrors, as they
provide high reflectivity with only a single suspended layer of patterned
dielectric material. However, due to limitations in nanofabrication, these
devices are usually not wider than 300 $\mu$m. Here we experimentally
demonstrate suspended PhC mirrors spanning areas up to 10$\times$10 mm. We
overcome limitations imposed by the size of the PhC and measure reflectivities
greater than 90% on 56 nm thick mirrors at a wavelength of 1550 nm -- an
unrivaled performance compared to PhC mirrors with micro scale diameters. These
structures bridge the gap between nano scale technologies and macroscopic
optical elements.
