Abstract
The lattice-paramater fluctuations seen in blue-phase II are studied by quasi-elastic light scattering. The spectrum in frequency and k-space, I(q,v), is expressible as S(v)A(q). In the range 4–3500 Hz, S(v) could be fitted to a sum of two central lorentzians plus a constant. Below 4 Hz, there was excess noise with at least two more characteristic frequencies. The spectra show that the fluctuating quantity is neither a simple relaxation nor just a propagating wave, but something more complex.