论文标题
去除由于具有较厚底物的多层结构传播的超短脉冲的回声引起的光谱失真
Removal of spectral distortion due to echo for ultrashort pulses propagating through multilayer structures with thick substrate
论文作者
论文摘要
考虑到时间域光谱法，尤其是THZ时域光谱的广泛应用，通常需要通过多层结构进行传播的探针脉冲建模。由于多层通常在底物上生长的厚度要比其他层厚得多，因此探针脉冲的传输包括一系列由底物接口处的多个反射引起的回声脉冲。实验通常测量时间曲线并仅从第一个传输脉冲构造传输频谱。由于典型的底物导致与光谱带宽相当的跨度的时间，因此第一个传输的脉冲光谱和完整的透射光谱可能会有所不同。因此，理论上重要的是在没有回声的情况下对传输进行建模，以便能够直接与实验结果进行比较。在这里，我们提出了一种方法，可以优雅，易于理论上从传输频谱中删除回声，而无需傅立叶转换信号两次。没有ECHO的传输脉冲的光谱将在没有其他数值步骤的情况下进行分析产生，从而在处理较大规模的计算时降低了计算时间和程序复杂性。
Given the wide range of applications of time-domain spectroscopy, and particularly THz time-domain spectroscopy, the modelling of a probe pulse propagating through a multilayered structure is often required. Due to the fact that the multilayers are usually grown on a substrate much thicker than the other layers, the transmission of a probe pulse includes a series of echo pulses caused by the multiple reflections at the substrate interfaces. Experiments often measure the time profile and construct the transmitted spectrum only from the first transmitted pulse. Due to the fact that typical substrates lead to times of crossing comparable to the spectral bandwidth, the first transmitted pulse's spectrum and the full transmitted spectrum can be importantly different. It is therefore important to theoretically model the transmission without the echo, to be able to directly compare with experimental results. Here we propose a method to elegantly and easily theoretically remove the echo from the transmission spectrum, without Fourier transforming the signal twice. The spectrum of the transmitted pulse without echo will be produced analytically without additional numerical steps, reducing computational time and program complexity when dealing with larger scale computing.
