Amit Kumar, R. Rai, Nikolas Podraza, Sava Denev, Mariola Ramirez, Ying-Hao Chu, Jon Ihlefeld, Tassilo Heeg, Jurgen Schubert, Darrell Schlom, Joseph Orenstein, R… 展开作者
Amit Kumar, R. Rai, Nikolas Podraza, Sava Denev, Mariola Ramirez, Ying-Hao Chu, Jon Ihlefeld, Tassilo Heeg, Jurgen Schubert, Darrell Schlom, Joseph Orenstein, R. Ramesh, Robert Collins, Janice Musfeldt, Venkatraman Gopalan
Using spectroscopic ellipsometry, the refractive index and absorption versus wavelength of the ferroelectric antiferromagnet Bismuth Ferrite, BiFeO_3 is reported. The material has a direct band-gap at 442 nm wavelength (2.81 eV). Using optical second harmonic generation, the nonlinear optical coefficients were determined to be d_15/d_22 = 0.20 +/- 0.01, d_31/d_22 = 0.35 +/- 0.02, d_33/d_22 = -11.4 +/- 0.20 and |d_22| = 298.4 +/- 6.1 pm/V at a fundamental wavelength of 800 nm.
Comments on the paper: Optical reflectance, optical refractive index and optical conductivity measurements of nonlinear optics for L-aspartic acid nickel chloride single crystal
在纳米尺度上构造光学材料可以导致具有强烈改变的光学行为的人工有效介质或超材料。超材料可以提供广泛的线性光学特性,例如负折射率、双曲色散或在光学频率下的磁性行为。然而,非线性光学性质仅在图案化的金属膜中得到证实,这些金属膜具有高的光学损耗。在这里,我们表明,二阶非线性超材料也可以从非金属中心对称成分具有固有的低光吸收。在我们的原理验证实验中,我们已经迭代了三种不同成分的原子层沉积(ALD),A = Al $_2$ O $_3$,B = TiO $_2$和C = HfO $_2$。由于ABC和反向CBA序列不等价,因此所得到的ABC堆栈的中心对称性被破坏-这是非零二阶非线性的必要条件。据我们所知,这是第一次实现的大块非线性光学超材料。