The purpose of this NASA SBIR Phase I proposal is to develop a novel type of high resolving power diffraction gratings based on volume Bragg gratings technology. The key innovation to be used for creation of these gratings is the patented technology on production of high efficiency volume diffractive elements in photo-thermo-refractive (PTR) glass on which OptiGrate has an exclusive license from the University of Central Florida. Gratings with diffraction efficiency more than 90% and resolving power up to 20,000 will be demonstrated for the spectral analysis applications in the visible and near-IR spectra (from 400 to 2700 nm). These gratings will have 25- to 50-mm aperture with the spectral resolution down to 50 pm and less. This, to the best of our knowledge, will exceed parameters of all comparable gratings available nowadays. Moreover, PTR volume diffractive gratings are stable over time for decades, thermally-stable up to 400??C, their resistance to CW laser radiation exceeds 10 kW/cm^2, and laser-induced damage threshold is 10 and 40 J/cm^2 for 1- and 8-nm pulse width, respectively. Absorption of these gratings is only 0.1 cm^-1 at 1 um wavelength after exposure to 10 Mrad of gamma radiation.