An organic crystal with an exceptionally large optical second-harmonic coefficient: 2-methyl-4-nitroaniline

Abstract

We have grown and measured the optical second-harmonic coefficient dijk of the new nonlinear crystal 2-methyl-4-nitroaniline (MNA). We find that the dijk are very large with d12 being 5.8 times larger than d31 of LiNbO3 giving a birefringence phase-matching figure of merit d2/n3 which is 45 times larger than LiNbO3. The other coefficient d11 is 40 times larger than LiNbO3, giving a huge figure of merit which is 2000 larger than LiNbO3.