Development and application of the pulsed-laser super optical cavity

本研究的目的如下：(1)建立脉冲激光法布里-珀罗光腔技术。(2)改进激光线监测器，更好地了解KEK-ATF光束动力学。特别是利用高斯光束的高次模来提高激光线的空间分辨率。(3)对小巧、明亮的X射线源进行中试实验。在研究期间，我们取得了以下成果。对于第(1)点，我们将锁模脉冲激光注入到我们的法布里-珀罗光学腔中，获得了630的功率增益。通过反馈系统稳定地维持了共振状态。腔内平均功率为2.4kW，对应的峰值功率约为1 mW。到目前为止，束腰达到了178微米。虽然还有进一步提高的空间，但我们对这些结果感到满意。在目标(2)上，我们建立了稳定产生高斯模光束的方法。我们研究了它们的特征，证实它们都很好地符合理论预期。在TEM01模式下，测量了ATF阻尼环(KEK)的电子束尺寸。在第(3)点上，我们已经开始开发X射线源，将我们的腔体放入由射频枪直线加速器产生的电子束中。该腔体现已安装在束流直线加速器X射线探测器中，对X射线源的详细研究目前正在进行中。

The aims of this research are as follows : (1) To establish techniques of Fabry-Perot optical cavity using pulsed laser. (2) To improve laser wire monitors and to understand better KEK-ATF beam dynamics with it. In particular, to improve the laser wire spatial resolution using higher-modes of Gauss beam. (3) To perform pilot experiment toward a compact, bright X-ray source. During the research period, we have obtained the following results. Concerning to the point (1), we injected a mode-locked pulse laser into our Fabry-Perot optical cavity, and achieved a power gain of 630. The resonance condition was stably maintained by a feedback system. The averaged power in the cavity was 2. 4KW, corresponding to a peak power of about 1 MW. The beam waist achieved so far was 178 micro-meter. Although there is still room to improve further, we are satisfied with these results. On the goal (2), we established the way to stably produce higher-mode gauss beams. We studied their characteristics and confirmed that all agree well with the theoretical expectations. With the laser wire operating in the TEM01 mode, we measured the electron beam sizes of the ATF damping ring (KEK). On the point (3), we have begun developing an X-ray source by putting our cavity in an electron beam produced by a RF-gun linac. The cavity is now installed in the beam linac X-ray detection and detailed studies of the X-ray source are now under way.