High-power, ultrafast µ-PL spectrometer

超快光谱学是了解发光材料和发光器件的光物理特性的重要工具。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重要作用，以开发下一代生物集成纳米和微激光器，用于广泛的生物医学应用。这将进一步加强对有机和生物极化激子激光器基本特性的研究。此外，该仪器非常适合指导高荧光和磷光材料的优化，目前开发用于超亮有机发光二极管（oled）及其在光遗传学中的应用以及电驱动有机激光器的研究。该光谱仪将能够激发活细胞内的纳米激光器，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、物理和化学变化的高灵敏度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，它将为纳米激光器和其他发光材料的光物理和降解机制提供新的见解，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，该系统被设计用于研究时间上超过9个数量级的时间现象，从1ps到1ms。为了在这些时间尺度上分析过程，样品的光激发必须在更快的亚皮秒时间尺度上发生。此外，要应用时间分辨光谱深入散射生物组织，将需要多光子激发。结合这些特性，同时提供足够的脉冲能量来激发超过其激光阈值的生物集成激光器，需要一个远远超过非线性显微镜中使用的标准激光器功率水平的泵浦源。因此，所提出的仪器基于波长可调谐（325 - 2500 nm）飞秒激光系统，具有特别大的脉冲能量（>200 nJ/脉冲），短脉冲持续时间（<200 fs）， MHz重复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）直到最近才开始商业化，首次允许光泵浦各种有机和无机半导体纳米激光器，其超短脉冲需要有效的非线性激发。总的来说，新仪器将在研究纳米和生物光子器件的时间现象方面具有独特的能力，并将大大提高测量能力。

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.