The forming of intensive Bragg diffraction maxima at recording of volume reflection holograms in dichromated gelatin (DCG) is investigated. The Bragg maxima up to 3rd order are received at use of special techniques of DCG layer processing. Mentioned maxima are located in the spectral range from UV up to IR wavelengths. The intensity of harmonics is high enough. By means of rigorous chain-matrix method the spectral characteristics of holographic structures with non-sinusoidal refractive-index modulation profile are calculated. Spectral curves for various sets of hologram parameters are computed and approximation of spectra received experimentally is conducted.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.