The paper provides an overview of the current state of sub-second pulses (SSP) studies in solar flares based on observational data from terrestrial instruments with high temporal, spatial, and spectral resolution in the microwave radio band. Due to the unique observational material accumulated in radio observations over the past 30 years, the characteristics of SSP were studied, their classification by spectral characteristics was performed. On this basis, the diagnostic possibilities of observations of solar flares with sub-second resolution on currently being created radioheliograps are revealed.