超高Q值mm级晶体回音壁微腔加工

Fabrication of ultra-high Q factor and millimeter-scale crystal echo wall microcavity

回音壁微腔具有超高Q值和极小的模式体积,在微波光子系统、非线性光学和量子光学等领域中具有广阔的应用前景。通过分析mm级氟化镁(MgF_(2))晶体回音壁微腔的损耗因素,确认了影响回音壁微腔品质因数的主要指标为材料等级和表面粗糙度。设计了mm级MgF_(2)晶体回音壁微腔的结构形式,使用DUV级MgF_(2)晶体,如果回音壁微腔表面粗糙度小于0.7 nm,则MgF_(2)晶体回音壁微腔的极限损耗理论计算值为4.781×10^(-11),对应的极限Q值为2.09×10^(10)。通过对MgF_(2)晶体回音壁微腔进行粗成型、精密车削、精密抛光,实现了高品质因数的微腔制造。测试结果表明,回音壁微腔的表面粗糙度Ra值为0.669 nm、微观形貌PV值为6.767 nm、品质因数为2.054×10^(9)@1550 nm。

The whispering gallery mode(WGM)microcavity has ultra-high Q factor and an extremely small pattern volume,and has a broad application prospect in the fields of microwave photonic systems,nonlinear optics and quantum optics.By analyzing the loss factors of millimeter-scale magnesium fluoride(MgF_(2))crystal WGM microcavity,it was confirmed that the main indexes affecting the quality factor of WGM microcavity were material grade and surface roughness.The structure of WGM microcavity was designed with millimeter-scale MgF_(2)crystal,and the DUV-level MgF_(2)crystal was used.Assuming the surface roughness of WGM microcavity was less than 0.7 nm,the theoretical calculation value of limit loss was 4.781×10^(−11)and the corresponding limit Q value was 2.09×10^(10).Through rough machining,precision turning and precision polishing of WGM microcavity of MgF_(2)crystal,the microcavity manufacturing with high quality factor was realized.The test results show that the surface roughness of WGM microcavity is 0.669 nm(Ra value),the shape error is 6.767 nm(PV value),and the quality factor is 2.054×10^(9)@1550 nm.