  We subject a monodomain cholesteric liquid crystal elastomer to uniaxial
strain perpendicular to its helical axis and study the response of its texture
to deformation. A combination of mechanical, optical and X-ray scattering
measurements confirms the prediction for the director rotation, coarsening and
then unwinding the cholesteric helix. The study of optical absorption of
circularly polarised light quantifies the complex dependence of the photonic
bandgap structure on strain and directly relates to the microscopic deformation
of elastomer. Agreement is found with the recently proposed theoretical
prediction of the photonic structure of cholesteric elastomers.
