超快高相干性可调光脉冲系统与量子调控应用

Based on the unique polarization effects of quantum well semiconductor optical amplifier (QWSOA), this project will be focused on the development of ultrafast high-coherence optical pulse generation and measurement system for quantum coherent control, and its application to quantum dots control, exploring new phenomena and obtaining high quality single-photon source. The main contents include: (1) Reveal the microscopic mechanism of ultrafast polarization rotation in QWSOA, establish the pulse transmission model including polarization effects in QWSOA, and clarify the mechanism of all-optical differentiation and pulse mode-locking based on QWSOA polarization; (2) Study the pulse differential process and the feedback compensation for electro-optic modulator by experiment, establish a set of ultrafast tunable coherent optical pulse generator, and obtain high frequency, high-coherence, and large tunable subpicosecond pulses (twin pulses); (3) Study pulse mode-locking method of the ring cavity based on polarization effects in QWSOA, and achieve stable fs optical sampling pulses; Establish the mathematical model of multi-photon absorption in GaAsP material, and study optical sampling pulse measurement based on two-photon absorption to realize measurement and monitoring of low-power subpicosecond pulses; (4) Apply the ultrafast coherent optical pulses to control the semiconductor quantum dots, observe the new features of the Rabi oscillation, Ramsey interference, and other quantum phenomena, and obtain high-frequency, high-coherence, and controllable single-photon source.The completion of this project will promote the field of quantum coherence control in China to the first class in the world.

基于量子阱半导体光放大器（QWSOA）独特的偏振效应，致力于发展面向量子相干调控的超快高相干性光脉冲系统，并应用于量子点调控，探索新现象，获得高质量单光子源。主要研究：(1)揭示QWSOA超快偏振旋转的微观机理，建立QWSOA包含偏振效应的脉冲传输模型，阐明基于QWSOA偏振效应的全光微分与脉冲锁模机制；(2)研究光脉冲的微分过程及电光调制器的反馈补偿，获得高重频、高相干性、大可调的亚皮秒双脉冲（孪生脉冲）；(3)探索QWSOA偏振效应的脉冲锁模机制，产生稳定的飞秒光采样脉冲；建立GaAsP材料多光子吸收数学模型，研究基于双光子吸收的光采样脉冲波形测量方法，实现对低功率亚皮秒脉冲波形的测量与监控；(4)应用超快相干光脉冲系统对量子点进行调控，探索Rabi振荡、Ramsey干涉等量子现象的新特征，制备高频、高相干性、可控单光子源。本项目的完成将使我国在量子相干调控领域率先进入国际先进行列。

本项目应用量子阱半导体光放大器（QW-SOA）独特的偏振效应，借助光学与全光信号处理方法，研制成功一种面向量子相干调控的高重频、可调节、高相干性光脉冲系统，并用于半导体量子点调控，获得了高频高相干单光子源。具体成果包括：.一、理论方面.应用密度矩阵方法研究QW-SOA微观量子效应与相干非线性过程，发现载流子的相干布居振荡是QW-SOA产生超快非线性偏振旋转效应的重要因素。应用Muller矩阵法，得到QW-SOA非线性偏振正交损失的解析式；在矩阵模型基础上，首次引入QW-SOA中增益与载流子浓度的对数关系，成功获得QW-SOA的量子模型，揭示了QW-SOA超快偏振效应的微观机理。.发现GaAsP的多光子吸收过程在外加电场或偏压作用下，可通过光子辅助隧穿非线性Franz-Keldysh效应得以加强，观察到多光子吸收系数在~5V偏压下近似增加一倍。揭示了多光子吸收的偏振依赖特性，其系数随1/4波片旋转角按正弦规律变化。.提出基于全光微分的脉冲压缩与整形方法，为高质量超短脉冲的产生提供了新的思路，使精密量子调控成为可能。首次发现调控激光与量子点荧光具有极为相似的光谱特性，指出相干散射是获得高相干单光子源的一种重要途径。.二、技术方面.研制成功一种高重频可调相干光脉冲系统。该系统由自主研发的基于PID控制工作点锁定的电光调制器产生高稳定光脉冲，再通过QW-SOA的超快偏振旋转实现全光微分，获得了高重频（20GHz）、高相干性（>1m）、双脉冲间隔30ps~3ns可调的亚皮秒（~1.6ps）脉冲序列。.首次应用QW-SOA的超快偏振效应，结合主动锁模以及偏振滤波技术，获得了高阶锁模飞秒脉冲系列，脉冲重频达10Ghz、峰值功率超过125mW。.实验成功一种基于多光子吸收的光采样脉冲波形测量方法，可直接测量低功率亚皮秒脉冲波形，测量精度的理论值约1fs，高于其他自相关法。.通过对自组装InAs/GaAs 量子点的相干调控，成功获得重复频率200MHz，相干长度25cm的可控单光子源。.此外，项目组还开发了以下实验系统：.1）高速QW-SOA驱动与控制系统；.2）高速低噪声单光子探测系统；.3）偏振相关损耗测试系统；.4）偏振模色散测试系统。