Transforming a green laser pointer in a self-mixing interferometer capable of submicrometer vibration sensing

Area of Science:

• Optics and Photonics
• Instrumentation and Measurement

Background:

• Interferometry is crucial for precise measurements.
• Commercial laser pointers offer potential for low-cost optical instrumentation.

Purpose of the Study:

• To develop a sensitive self-mixing interferometer using a modified commercial laser pointer.
• To demonstrate its capability for detecting minute vibrations and measuring displacement.

Main Methods:

• A commercial green laser pointer was modified by adding a photodiode and a glass beam splitter.
• The modified device was configured as a self-mixing interferometer.

Main Results:

• The interferometer achieved high sensitivity, detecting vibrations down to submicrometer amplitudes (approximately 13 nm resolution).
• Displacement measurements were possible with increments of half a wavelength (λ/2 = 266 nm).

Conclusions:

• A cost-effective and highly sensitive self-mixing interferometer can be constructed from a modified green laser pointer.
• This setup is suitable for applications requiring precise vibration analysis and displacement metrology.