基于zigzag板条多通放大窄线宽脉冲固体超荧光光源研究

Superfluorescence (SF) has continuous spectra, no relaxation oscillation, no mode jitter and high temporal stability, thus playing a significant role in many applications, such as optical coherence tomography, spectroscopy and materials processing. Here, based on the angular multiplexing nature of the zigzag slab, we propose a new approach to achieve an ultra-high gain while avoiding unwanted self-lasing caused by the residual optical-feedback for generating narrow-linewidth, pulsed SF sources in a multiple-pass amplifier system. In this project, the output property of the SF will be studied for both Nd:YAG and Nd:YVO4 slab gain mediums, including the output power, pulse shape, pulse duration, peak power, spectral center-wavelength and linewidth under the quasi-continuous-wave pumping and passive Q-switching mechanism. Through this project, we can not only deepen the acknowledgement to the characteristics of solid-state SF, but also promote the design concepts of narrow-linewidth, pulsed SF sources.

超荧光（SF）具有光谱连续、无弛豫振荡、无模跳、输出稳定等优点，因此在光学层析、光谱检测、材料加工等众多领域有着广泛的应用前景。基于ziazag板条角度选通特性，本课题提出经不同选通角多次通过单一板条增益模块实现超高的增益放大、同时有效地避免了残余回光自激，旨在对该新方法产生窄线宽脉冲SF光源进行探索性研究。针对Nd:YAG和Nd:YVO4两种板条增益介质，研究分析准连续泵浦和被动调Q下SF输出功率、脉冲形状、脉宽、峰值功率、光谱中心及线宽等特性规律。通过本课题研究，不但可以深化对固体SF特征的认识，也对窄线宽脉冲SF光源产生研究具有重要意义。

超荧光（SF）具有光谱连续、无弛豫振荡、无模跳、输出稳定等优点，因此在光学层析、光谱检测、材料加工等众多领域有着广泛的应用前景。本项目完成了板条多通放大超荧光产生动力学模型建立，分析掌握了放大通次、泵浦强度及泵浦脉宽等对输出特性的影响规律，通过合理选择这些要素可实现不同脉宽和峰值功率的光滑（无弛豫振荡尖峰）矩形脉冲；完成了一套多通放大超荧光光源实验系统设计搭建，准连续泵浦下首次实现了光滑脉冲和窄线宽连续光谱，获得脉宽百μs、峰值功率数kW和脉宽ns、峰值功率数MW短脉冲输出，中心波长实现23pm温升红移调谐、光谱线宽20pm（~5.3GHz），板条厚度和宽度方向光束质量分别为3.5/17；理论上，通过放大或者多个增益模块串接可以实现超荧光输出功率提升，由于输出光谱线宽很窄，可通过常规的非线性频率变换（倍频、和频、OPO等）方式实现波长拓展。通过本项目研究，深化了对固体超荧光特征的认识，也对窄线宽脉冲超荧光光源产生研究具有重要意义。