Detection and visualization of β-galactosidase (β-gal) is essential to reflect its physiological and pathological effects on human health and disease, but it is still challenging to precisely track β-gal in vivo owing to the limitation of current analytical methods. In our work, we reported a photoacoustic (PA) nanoprobe for selective imaging of the endogenous β-gal in vivo. Our nanoprobe Cy7-β-gal-LP was constructed by encapsulation of a near-infra red (NIR) dye Cy7-β-gal within a liposome (LP, DSPE-PEG2000-COOH). The dye Cy7-β-gal was synthesized based on a dye Cy-OH where the hydroxyl group was replaced by a β-D-galactopyranoside residue, which can be recognized by β-gal as an enzyme hydrolytic site. With the addition of β-gal, the absorbance of Cy7-β-gal exhibited a significant red shift with the absorption peak moved from 600 nm to 680 nm, which should generate a switch-on PA signal at 680 nm in the presence of β-gal. In addition, as the fluorescence of the dye was totally quenched due to aggregation within the liposome, Cy7-β-gal-LP exhibited high PA conversion e±ciency. With the nanoprobe, we achieved the selective PA detection and imaging of β-gal in the tumor-bearing mice.

稀土发光材料相比于传统有机荧光染料在生物成像、分子检测和传感等领域具有独特的优势。目前, 稀土发光生物探针主要以可见光发射为主, 此类探针受限于组织穿透深度, 应用范围较窄。具有较大组织穿透能力的近红外(NIR)稀土发光生物探针, 由于其发光效率较低而少有报到。本工作合成了一种新型近红外发光的卟啉镱-铂配合物, TFPYb-Pt, 表征并测试了该配合物的光物理性质。实验证实TFPYb-Pt具有较大的NIR发光效率(980/1 030 nm,Фem=0.37)和较长的NIR发光寿命(τ=49μs), 表明该配合物可望被用于开发新型生物NIR发光探针。

稀土近红外发光材料具有独特的光物理性质, 如发光谱带窄、较大的Stock位移、荧光寿命长可达毫秒级等, 在医学诊断和成像、免疫分析等热门领域具有重大的应用前景。但由于跃迁选择定则, 稀土离子本身的吸收系数较小, 需要用特定的生色团对其进行敏化, 以增强其发光性能。在众多生色团中, 卟啉化合物由于其激发态能级与近红外发光的稀土离子能级较为匹配, 可以较好的敏化稀土离子, 获得较高的近红外发光效率, 因此, 近年来受到了极大的关注。本文总结了近年来近红外发光卟啉稀土配合物在生命科学领域中的应用研究进展, 并对其发展前景进行了展望。

由于光声效应产生光声压分布图像，所以当强散射介质中的模拟吸光组织在受到短脉冲激光照射时，该声压分布会经声透镜成像在像平面上。在像平面上利用线性超声探测器阵列获取光声信号并传递给高速数据采集卡进行数据采集，可由程序重构出光声图像。设计的光声层析成像系统可以采集记录一定深度的数据，成像时只要在所采集到的数据中选取不同列数即可同时获得强散射介质多层样品不同层面的光声图像。实验成功地获得了强散射介质内多层样品不同层面的光声层析图像。该成像方法无需进行复杂的算法重建，且可以同时实现多层样品不同切面的光声成像。

SiO2/TiO2/methylcellulose composite materials processed by the sol-gel technique were studied for optical waveguide applications. With the help of methylcellulose, an organic binder, SiO2/TiO2/methylcellulose hybrid thick films were prepared by a single spin-coating processes. After annealing at 70 Celsius degree for an hour, 2.5-μm crack-free and dense organic--inorganic hybrid optical films with a refractive index of 1.537 were achieved. Optical losses of plane waveguide made up of those films and ordinary slide glass substrate are around 0.3 dB/cm at 650 nm. Scanning electronmicroscopy (SEM) and UV-visible spectroscopy (UV-VIS), have been used to characterize the thick films.

We have proposed and demonstrated a double-pass ytterbium-doped fiber amplifier using an optical circulator and a fiber Bragg grating as reflector. When the signal has passed through the ytterbium-doped fiber once, it reflects off a 0.2-nm passive fiber Bragg grating filter. This reduces amplified spontaneous emission (ASE) noise from the first pass. The input signal light is amplified both forward and backward through ytterbium-doped fiber. With this double-pass configuration, 1053.15-nm unsaturated signal gain of 28 dB, gain coefficient of 1.1 dB/mW, and noise figure of less than 4 dB are achieved at 977-nm pump power of 68 mW. It is also found that this double-pass configure provides enhancing gain coefficient and improving noise figure by comparison with single-pass configuration.

The band-pass characteristic of fiber grating Michelson interferometer is analyzed, which acts as both band-pass filter and Q-switch. An erbium-doped fiber ring laser based on fiber grating Michelson interferometer is implemented for producing single longitudinal mode CW operation with 5 MHz spectral linewidth and up to 6 mW output power. In Q-switched operation, stable fiber laser output pulses with repetition rate of 800 Hz, pulse width of 0.6 μs, average power of 1.8 mW and peak power of 3.4 W are demonstrated. The peak power and average power of the Q-switched pulses are varied with the repetitionrate.