Abstract

Yellow organic terahertz (THz) generation crystals such as BNA [1,2] and MNA [3] and NMBA [4] have lower absorption cutoffs in the visible region than orange-red organic THz generators like DAST and OH-1. This allows these crystals to be pumped with the output of a Ti:sapphire laser system, but they cannot be pumped at high fluences without melting. Originally demonstrated for BNA [2], we have developed a way of improving the damage threshold by bonding these yellow crystals directly to sapphire plates without any adhesive. For this work, we fused yellow NLO crystals MNA and NMBA to sapphire, as well, improving their damage threshold and allowing us to make use of the full power of our Ti:sapphire laser system. The high thermal conductivity of the sapphire dissipates laser heat and enables the crystals to be pumped at higher fluences without melting—allowing us to achieve greater THz electric fields. To increase THz output even further, we have developed a layered sandwich structure to reduce reflective losses that occur between the air and the THz generation crystal [5].

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