High-power, ultrafast µ-PL spectrometer

超快光谱是理解发光材料和发光器件光物理的重要工具。本提案中描述的高功率、超快µ-PL光谱仪在纳米生物光子学中心的战略计划中发挥着重要作用，该计划旨在开发用于广泛生物医学应用的下一代生物集成纳米和微激光。它将进一步加强对有机和生物极化激光基本性质的研究活动。此外，该仪器非常适合于指导高荧光和磷光材料的优化，这些材料目前是为超亮有机发光二极管(OLED)及其在光遗传学和电驱动有机激光研究中的应用而开发的。该光谱仪将能够激发活细胞内的纳米激光，并确定它们在单光子和多光子泵浦下的发射动力学。纳米激光器的时间特性对几何、物理和化学变化高度敏感，这将使该仪器成为开发基于生物集成激光器的新型传感机制的有力工具。此外，它还将为纳米激光和其他发光材料的光物理和退化机制提供新的见解，以指导它们未来的优化。为了能够在如此广泛的材料和设备上工作，时间分辨光谱仪包括一个条纹-相机系统，该系统旨在研究从1ps到1ms的9个数量级的时间现象。为了分析这些时间尺度上的过程，样品的光激发必须发生在更快的亚皮秒时间尺度上。此外，为了在散射生物组织的深处应用时间分辨光谱，将需要多光子激发。将这些特性结合在一起，同时提供足够的脉冲能量来激发高于其激光阈值的生物集成激光器，需要一个远远超过用于非线性显微镜的标准激光器的泵浦源。因此，该仪器基于波长可调(325-2500 nm)的飞秒激光系统，具有极大的脉冲能量(&gt；200 nJ/脉冲)、短脉冲持续时间(&lt；200 fs)、MHz重复频率和群速度色散校正。这种高功率激光器(泵浦阶段的功率为80W)直到最近才投入商业使用，首次允许利用有效的非线性激发所需的超短脉冲来光学泵浦广泛的有机和无机半导体纳米激光器。总体而言，新仪器在研究纳米和生物光子设备的时间现象方面将是独一无二的，并将极大地提高测量能力。

Ultrafast spectroscopy is an essential tool to understand the photophysics of luminescent materials and light emitting devices. The high-power, ultrafast µ-PL spectrometer described in this proposal plays a major role in the strategic plan of the Centre of NanoBioPhotonics to develop the next generation of biointegrated nano and microlasers for a wide range of biomedical applications. It will further critically enhance the research activities on fundamental properties of organic and biological polariton lasers. In addition, the instrument is ideally suited to guide the optimisation of highly fluorescent and phosphorescent materials, currently developed for ultra-bright organic light emitting diodes (OLEDs) and their application in optogenetics as well as for research on electrically driven organic lasers. The spectrometer will be able to excite nanolasers within live cells and determine their emission dynamics under single and multiphoton pumping. The high sensitivity of the temporal characteristics of nanolasers to geometric, physical and chemical changes will make this instrument a powerful tool for the development of novel sensing mechanisms based on biointegrated lasers. In addition, it will provide new insights into the photophysics and degradation mechanisms of nanolasers and other luminescent materials to guide their future optimisation.To be able to work on such a wide range of materials and devices, the time-resolved spectrometer comprises a streak-camera system that is designed to investigate temporal phenomena that stretch over 9 orders of magnitude in time, from 1 ps to 1 ms. To analyse processes on these timescales, the optical excitation of the sample must occur on an even faster, sub-picosecond time scale. In addition, to apply time-resolved spectroscopy deep within scattering biological tissue, multiphoton excitation will be required. Combining these properties while also providing enough pulse energy to excite biointegrated lasers above their lasing threshold requires a pump source that by far exceeds the power level of standard lasers used in non-linear microscopy. The proposed instrument is therefore based around a wavelength-tuneable (325 – 2500 nm) femtosecond laser system with exceptionally large pulse energy (>200 nJ/pulse), short pulses duration (<200 fs), MHz repetition rate, and group-velocity dispersion correction. Such high-power lasers (>80 W at the pump stage) have only recently become commercially available, allowing for the first time to optically pump a broad range of organic and inorganic semiconductor-based nanolasers with the ultra-short pulses required for efficient nonlinear excitation. Overall, the new instrument will be unique in its ability to study temporal phenomena of nano and biophotonic devices and will greatly improve the measurement capability.