We report the first observation of “quasi-Planck” spectra of capillary turbulence on the surface of liquid hydrogen in the dissipation domain. Capillary waves have been driven by low-frequency random force. We have observed that the frequency spectrum of surface elevation changes its dependence from power-like 〈|ηω2|〉 ∼ ω−2,8 at middle-frequency domain to “quasi-Planck” distribution ∼eω/ωd at higher frequencies. The frequency ωd is proportional to the boundary frequency between inertial interval and dissipation domain and it is scaled up with the increase of driving force.
