Second-harmonic generation in lithium niobate nanowires for local fluorescence excitation.
Second-harmonic generation in lithium niobate nanowires for local fluorescence excitation.
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DOI：
10.1364/oe.21.019012
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发表时间：
2013-08
期刊：
影响因子：
3.8
通讯作者：
A. Sergeyev;R. Geiss;A. Solntsev;A. Steinbrück;F. Schrempel;E. Kley;T. Pertsch;R. Grange
中科院分区：
文献类型：
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作者：
A. Sergeyev;R. Geiss;A. Solntsev;A. Steinbrück;F. Schrempel;E. Kley;T. Pertsch;R. Grange
研究了自顶向下离子束增强刻蚀法制备的铌酸锂（LiNbO（3））纳米线的非线性光学性质。首先，我们演示了二次谐波（SH）光在LiNbO（3）纳米线中的产生和传播，LiNbO（3）纳米线的典型矩形横截面为400 x 600 nm（2），长度从10到50 μm。然后，我们显示了4 '，6-二脒基-2-苯基吲哚（DAPI）染料的局部荧光激发与传播的SH信号在标准浓度的生物应用。通过测量检测到的平均功率的传播的基波（FH）和SH信号在输出的NW，我们直接证明了主导作用的SH信号可能的双光子激发过程中的FH在DAPI染料。我们估计，63 ± 6 pW的传播SH平均功率所需的可检测的染料激发。最后，我们对SH光的波导进行建模，以确定最小的NW横截面（约40 × 60 nm（2）），其可能能够激发具有低于细胞损伤阈值的FH强度的荧光。
We study the nonlinear optical properties of lithium niobate (LiNbO(3)) nanowires (NWs) fabricated by a top-down ion beam enhanced etching method. First, we demonstrate generation and propagation of the second-harmonic (SH) light in LiNbO(3) NWs of typical rectangular cross-sections of 400 x 600 nm(2) and length from 10 to 50 μm. Then, we show local fluorescent excitation of 4',6-diamidino-2-phenylindole (DAPI) dye with the propagated SH signal in standard concentrations as for biological applications. By measuring the detected average power of the propagated fundamental harmonic (FH) and the SH signal at the output of the NWs, we directly prove the dominating role of the SH signal over possible two-photon excitation processes with the FH in the DAPI dye. We estimate that 63 ± 6 pW of the propagated SH average power is required for detectable dye excitation. Finally, we model the waveguiding of the SH light to determine the smallest NW cross-section (around 40x60 nm(2)) which is potentially able to excite fluorescence with a FH intensity below the cell damage threshold.