This work presents and discusses the features of a monolithic Programmable Micro Diffractive Grating (PMDG) fabricated over a lithium niobate substrate, which can be used to synthetize the visible and near-infrared spectra of important analytes, including dangerous materials (chemically aggressive, toxic or explosive gases). The functional core of the device consists of a periodic arrangement (array) of ridge waveguides whose optical delay (phase shift) is controlled electrically via the linear electro-optical (Pockels) effect. By distinctly polarizing every waveguide composing the comb with a suitable voltage, the collective transparency of the grating can be tailored so that the output far-field, at a predetermined diffraction angle, may reproduce a spectral distribution of interest. Therefore, this device can serve as universal reference cell in a correlation spectroscopy set-up, with particular interest for safety and security …