Future inter-satellite clock comparison on high orbit will require optical time and frequency transmission technology between moving objects.Here,we demonstrate robust optical frequency transmission under the conditio...Future inter-satellite clock comparison on high orbit will require optical time and frequency transmission technology between moving objects.Here,we demonstrate robust optical frequency transmission under the condition of variable link distance.This variable link is accomplished by the relative motion of a single telescope fixed on the experimental platform to a corner-cube reflector(CCR)installed on a sliding guide.Two acousto–optic modulators with different frequencies are used to separate forward signal from backward signal.With active phase noise suppression,when the CCR moves back and forth at a constant velocity of 20 cm/s and an acceleration of 20 cm/s^(2),we achieve the best frequency stability of 1.9×10^(-16) at 1 s and 7.9×10^(-19) at 1000 s indoors.This work paves the way for future studying optical frequency transfer between ultra-high-orbit satellites.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFB0408300)the National Natural Science Foundation of China(Grant No.62175246)+2 种基金the Natural Science Foundation of Shanghai,China(Grant No.22ZR1471100)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.YIPA2021244)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0300701).
文摘Future inter-satellite clock comparison on high orbit will require optical time and frequency transmission technology between moving objects.Here,we demonstrate robust optical frequency transmission under the condition of variable link distance.This variable link is accomplished by the relative motion of a single telescope fixed on the experimental platform to a corner-cube reflector(CCR)installed on a sliding guide.Two acousto–optic modulators with different frequencies are used to separate forward signal from backward signal.With active phase noise suppression,when the CCR moves back and forth at a constant velocity of 20 cm/s and an acceleration of 20 cm/s^(2),we achieve the best frequency stability of 1.9×10^(-16) at 1 s and 7.9×10^(-19) at 1000 s indoors.This work paves the way for future studying optical frequency transfer between ultra-high-orbit satellites.
文摘目的探讨三维斑点追踪成像(3-dimensional speckle tracking imaging,3D-STI)技术评价妊娠高血压综合征(pregnancy-induced hypertension syndrome,PIHS)患者产前和产后左心室收缩功能的临床价值。方法采用3D-STI测量32例待产的PIHS孕妇(PIHS产前组)、30例产后3个月复查的PIHS产妇(PIHS产后组)及40例待产的正常孕妇(正常对照组)的左心室整体纵向收缩期峰值应变(left ventricle global longitudinal strain,LVGLS)、左心室整体径向收缩期峰值应变(left ventricle global radial strain,LVGRS)、左心室整体圆周收缩期峰值应变(left ventricle global circumferential strain,LVGCS)、左心室整体面积收缩期峰值应变(left ventricular global area peak systolic strain,LVGAS)值,并进行比较。结果与正常对照组比较,PIHS产前组LVGLS值降低(P<0.05),LVGRS、LVGCS、LVGAS值无明显变化(P>0.05);PIHS产后组LVGLS、LVGRS、LVGCS、LVGAS值无明显变化(P>0.05)。与PIHS产前组比较,PIHS产后组LVGLS值升高(P<0.05),LVGRS、LVGCS、LVGAS值无明显变化(P>0.05)。结论 3D-STI技术通过评估PIH患者产前及产后3个月左心室的三维整体应变,可反映PIH患者分娩前后左心室整体收缩功能的改变,为临床早期判断及治疗提供参考。
