High spectral resolution LIDAR source at 1 kHz amplifying spectrally single mode ns-pulses with active ASE suppression

In our work, we developed a LIDAR (LIght Detection And Ranging) source with high output energy of over 12 mJ and narrow spectral bandwidths < 30 MHz at a repetition rate of 1 kHz. Our approach contains the amplification of pulses with E ≤ 50 nJ out of a low energy seed source at the central wavelength 1064.475 nm and spectral width < 20 MHz. The seed pulses were amplified in four sequential Nd:YVO₄ amplification stages. The amplification of parasitic ASE (Amplified Spontaneous Emission) from stage to stage due to the high emission cross section of the material had to be suppressed to guarantee maximal population inversion for the seed pulse amplification. By temporal separation of ASE and seed pulses with an AOM between the first and the second amplification stage, ASE could be suppressed sufficiently.