A self-mixing interferometer is proposed to detect the change of refractive index of a sample. As light source, the developed measurement system uses a blue emitting GaN laser diode. An external mirror, driven by a piezo nanopositioner, is used to reflect the light and produce an interference signal which is detected with the monitor photodiode of the laser. The change of the refractive index is demonstrated by changing the optical path length of the external cavity by changing the offset-voltage of the piezo positioner. This introduces a phase difference to the interference signal. The results show that by considering the measured sensitivity of the setup, about 1,9x10-7 changes in the refractive index can be detected in 1 cm optical path length.
|Title of host publication||Proceedings of ODIMAP V|
|Subtitle of host publication||5th Topical Meeting on Optoelectronic Distance/Displacement Measurements and Applications|
|Place of Publication||Spain|
|Publisher||IEEE Institute of Electrical and Electronic Engineers|
|Publication status||Published - 2006|
|MoE publication type||A4 Article in a conference publication|
|Event||5th Topical Meeting on Optoelectronic Distance/Displacement Measurement and Applications - Madrid, Spain|
Duration: 2 Oct 2006 → 4 Oct 2006
|Conference||5th Topical Meeting on Optoelectronic Distance/Displacement Measurement and Applications|
|Abbreviated title||ODIMAP V|
|Period||2/10/06 → 4/10/06|
- fringe pattern analysis
- time domain methods
Määttälä, M., Hast, J., & Myllylä, R. (2006). Refractive index devetion using a self-mixing interferometer. In Proceedings of ODIMAP V: 5th Topical Meeting on Optoelectronic Distance/Displacement Measurements and Applications (pp. 315-320). IEEE Institute of Electrical and Electronic Engineers .