Experimental study of crystal anisotropy based on ultra-precision cylindrical turning of single-crystal calcium fluoride

Shunya Azami, Hiroshi Kudo, Yuta Mizumoto, Takasumi Tanabe, Jiwang Yan, Yasuhiro Kakinuma

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


To realize ultimately efficient signal processing, it is necessary to replace electrical signal processing circuits with optical ones. The optical micro-resonator, which localizes light at a certain spot, is an essential component in optical signal processing. Single-crystal calcium fluoride (CaF2) is the most suitable material for a highly efficient optical micro-resonator. The CaF2 resonator can only be manufactured by ultra-precision machining processes, because its crystal anisotropy does not allow the application of chemical etching. However, the optical micro-resonator's performance depends definitely on the surface integrity. This study investigated the relationship between surface quality after ultra-precision machining and crystal anisotropy. Firstly, crack initiation was investigated on the (1 0 0), (1 1 0), and (1 1 1) planes using the micro-Vickers hardness test. Secondly, brittle-ductile transition was investigated by orthogonal cutting tests. Finally, cutting performance of cylindrical turning was evaluated, which could be a suitable method for manufacturing the CaF2 resonator. The most difficult point in cylindrical turning of CaF2 is that the crystalline plane and cutting direction vary continuously. In order to manufacture the CaF2 optical micro-resonator more efficiently, analysis was conducted on crack initiation and surface quality of all crystallographic orientations from the perspective of slip system and cleavage.

Original languageEnglish
Pages (from-to)172-181
Number of pages10
JournalPrecision Engineering
Publication statusPublished - 2015 Apr 1


  • Crystal anisotropy
  • Micro-Vickers
  • Orthogonal cutting
  • Single-crystal calcium fluoride
  • Surface quality
  • Ultra-precision cylindrical turning

ASJC Scopus subject areas

  • Engineering(all)


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