Basic research for realization of an unidirectional optical amplifier

迄今为止，还没有任何一种有源器件能够实现信号的单向放大和传输。本研究的课题是利用真空环境中发射的电子束实现单向光放大器，由于光波导具有折射率，光在介质波导中的传播速度比在自由空间中慢。通过介质波导传播的光学光部分地穿透到环境空间中。当电子束沿着波导的表面沿着辐射并且其速度与可见光的传播速度一致时，电子束的能量可以转移到可见光。也就是说，光学光被电子束放大。相反方向传播的光学光的其他分量由于传播速度非常快而永远不会被放大。放大可见光的另一个条件是光应该具有 关于我们 在所辐射的电子束的方向上的电子部件。然后光的TM分量可以被放大。以上是我们所提出的单向光放大器的原理，在获得资助之前，我们已经为此课题建立了一个基于真空系统的实验装置。我们在2000年购买了一个电子透镜的财政支持，使更强的电子束聚焦。我们还改进了介质波导的结构，通过在波导表面附加电极来释放带电电子，直到输出光的测量变得如此不稳定。结果表明，在芯层为蒸发非晶硅膜的波导中，导光强度得到了增强。我们预期这种增强应该是我们提出的放大现象，因为TM分量改变电子束加速电压的特性与我们的理论计算很好地吻合。然而，我们仍在调查的特性的细节，因为TE组件也在实验中增强。这一意外现象可能是由于介质材料本身的光吸收和光发射引起的。我们也开始了实验，采用SOI衬底作为波导，并制作了放大器输入端口的波导。然而，我们还没有得到这些先进实验的合适数据。少

Any active device which can amplify and transfer the signal in single direction has not been invented yet. Subject of this research was to realize a unidirectional optical amplifier by utilizing an electron beam which is emitted in vacuum environment.The propagation speed of the optical light in an dielectric wave-guide is slower than that in the free space, because the optical wave-guide has the refractive index. The optical light propagating by the dielectric wave-guide partly penetrates into the environmental space. When an electron beam is radiated along surface of the wave-guide and whose velocity coincides with the propagating speed of the optical light, energy of the electron beam can transfer to the optical light. That is, the optical light is amplified by the electron beam. Other component of the optical light which propagates counter direction is never amplified because the propagation speed is extremely. Another condition to amplify the optical light is the light should has … More an electric component in the direction of the radiated electron beam. Then the TM components of the light can be amplified. Mentioned above is the mechanism of our proposed unidirectional optical amplifier.We had already being constructed an experimental set basing on a vacuum system toward this subject before this financial support was supported. We purchased an electron lens in 2000 by this financial support to make stronger focusing of the electron beam. We also improved structure of the dielectric wave-guide by attaching electrodes to release charged electron on surface of the wave-guide, until when measuring of the output light had been so much unstable. As the result, we observed enhancing of the guided optical light in wave-guide whose core layer wa made with evaporated a-Si film. We are expecting this enhancing should be the phenomenon which we has proposing as the amplification because characteristics of TM components for varying the acceleration voltage of the electron beam is well coincide with our theoretical calculation. However, we are still investigating details of the characteristics, because TE components were also enhanced in experiment. This unexpected phenomena may be caused by optical absorption and emission by the dielectric material itself.We also started the experiment by applying the SOI substrate as the wave-guide and fabrication of a wave-guide for the input port in the amplifier. However, we have not got suitable data on these advanced experiments. Less