Hleb E Y, Lapotko D O
A V Lykov Heat and Mass Transfer Institute, 15 Brovka Street, Minsk 220072, Belarus.
Nanotechnology. 2008 Sep 3;19(35):355702. doi: 10.1088/0957-4484/19/35/355702. Epub 2008 Jul 18.
Photothermal (PT) efficacy and damage thresholds of gold nanoparticles (NP)-spheres, rods and silica-gold shells-were experimentally studied during their excitation with nanosecond laser pulses at the fluence levels at and above the NP damage threshold. The maxima of PT efficacy of gold NPs with near-infrared (NIR) plasmon resonances (gold rods and shells) and the minima of their damage thresholds were found to be shifted from their plasmon resonance NIR wavelengths into non-resonant visible wavelengths. This suppression of PT efficacy of NIR plasmon resonances (bleaching) was found to be up to 18 times for the rods and up to 22 times for the shells. During laser-induced deterioration the NPs maintained their PT properties at least within 40-150 ns after exposure to laser pulses. PT properties of the gold NPs can be enhanced with the pulse train mode within the above time. The PT bubbles generated around superheated NPs were used as their optical markers and allowed us to quantify PT efficacy of plasmon resonance through the bubble parameters under the conditions when other methods of NP detection are not applicable.
在纳秒激光脉冲以等于或高于金纳米颗粒（NP）损伤阈值的能量密度激发金纳米颗粒球体、棒体以及二氧化硅-金壳的过程中，对其光热（PT）效应和损伤阈值进行了实验研究。发现具有近红外（NIR）等离子体共振的金纳米颗粒（金棒和金壳）的光热效应最大值及其损伤阈值最小值从其等离子体共振近红外波长移至非共振可见光波长。对于金棒，这种近红外等离子体共振光热效应的抑制（漂白）高达18倍，对于金壳则高达22倍。在激光诱导劣化过程中，纳米颗粒在暴露于激光脉冲后至少在40 - 150纳秒内保持其光热特性。在上述时间内，金纳米颗粒的光热特性可通过脉冲序列模式得到增强。在过热纳米颗粒周围产生的光热气泡用作其光学标记，并且在其他纳米颗粒检测方法不适用的条件下，使我们能够通过气泡参数量化等离子体共振的光热效应。
