Attenuation of the intensities of spectral components of a multiwavelength pulsed laser system by means of the Bragg diffraction of radiation by several acoustic waves

A method for controlling precisely the intensities of several spectral components of radiation generated by a multiwavelength laser system is described. The method is based on the use of simultaneous Bragg diffraction by a set of acoustic waves of corresponding frequencies and adjustment of their amplitudes. The efficiency of the proposed method is demonstrated by the example of a multiwavelength system based on a pulsed Nd:YAG laser (1064 nm) with intracavity parametric generation of a signal wave (1572 nm) and extracavity light conversion into higher harmonics and sum frequencies. An independent control of intensity ratio for four spectral components in the visible range (452, 532, 635, and 786 nm) is obtained by precisely controlled attenuation of acoustic-wave amplitudes using an original 4-channel acousto-optical polychromator.