Standard SH option (first option highlighted above) is with D*KDP crystal – conversion efficiency ~50% to 532nm (1.7J)
LBO SH option is with LBO crystal – conversion efficiency 60-70% to 532 nm (2.1J).
The crystal size for the standard SH and LBO SH is the same but the material is different.
RLI is ‘Relay Imaging’ – see Ekpla explanation -
'Without RLI beam propagates from oscillator to amplifier to SH crystal in free space and diffraction rings form.
With RLI we image translate between oscillator <-> amplifier <-> SH crystal. Each image translation (or RLI) stage consist of two lenses and vacuum cell. Image translation does not let diffraction rings to form and we have smooth beam profile after SH crystal. For best performance we recommend an external translation system to customer Ti:Sapphire crystal as well.'
So - the difference between two SH options above are energy and beam profile.