Microlaser assisted diamond turning of precision silicon optics

Abstract

The application of microlaser assisted machining of precision optical components made of optical grade single-crystal Si is reviewed. An optical raytracing model is developed and used for predicting the laser interaction with the workpiece. Optical characterization of the system is shown to be in good agreement with that predicted by the model. Using the information from the simulation and experimental validation, the laser-assisted diamond turning of single-crystal Si samples is shown to have exhibited little to no brittle fracture on the surface and the potential of extending the diamond tooling life by 150%.

Cutting performance of laser assisted diamond turning of calcium fluoride with different crystal orientations

“…It is speculated that absorbed laser power thermally softens the material and facilitates ductile material removal, see Figure 1(a). The localized heating due to laser is limited to an area of < 300 µm ⇥ 300 µm, most of the heat absorbed by the material is dissipated through the chips [19].…”

“…The assembly holding the LDOS comprises of micrometers that allow the alignment of laser beam with respect to the tool edge. The µ-LAM process has proved to enhance the cutting performance of IR materials like Silicon, Ge and ZnS [19][20][21]. Machining of single-crystal Si samples using the µ-LAM process exhibited little to no brittle fracture on the surface and the potential of extending the diamond tooling life by 150% [19].…”

“…The µ-LAM process has proved to enhance the cutting performance of IR materials like Silicon, Ge and ZnS [19][20][21]. Machining of single-crystal Si samples using the µ-LAM process exhibited little to no brittle fracture on the surface and the potential of extending the diamond tooling life by 150% [19]. Machining germanium using the µ-LAM process produced lower post machining residual stresses on the surface relative to conventional diamond turning.…”

Ultraprecision laser-assisted diamond machining of single crystal Ge

“…Research work published by this group in the past has demonstrated the capabilities of the -LAM process in UPM of single crystalline materials such as silicon [17,18]. The main reason for the application of a laser beam concurrent with the SPDT process, is to lower the material local hardness at the cutting zone.…”

“…2(b) explicitly highlights the di erent zones on the cutting tool. Additional details and information regarding alignment and calibration of the laser beam can be found in [17].…”