Simultaneous thickness and group index measurement with a single arm low-coherence interferometer.

Area of Science:

• Optical Physics
• Metrology
• Materials Science

Background:

• Accurate measurement of optical properties is crucial for material characterization.
• Traditional interferometers can be complex and unstable.
• Need for a compact and stable system for measuring transparent materials.

Purpose of the Study:

• To develop and demonstrate a single-arm low-coherence interferometer.
• To directly measure the physical thickness and group refractive index of transparent samples.
• To provide a more compact and stable alternative to dual-arm interferometers.

Main Methods:

• Utilized a single-arm, common-path low-coherence interferometer.
• Employed optical principles for direct measurement of thickness and refractive index.
• Tested on fused silica, crown glass, and borosilicate cover glass samples.

Main Results:

• Achieved uncertainties in the third decimal place for refractive index values.
• Determined sample thicknesses with accuracy within 2 μm.
• Demonstrated the system's stability and compactness compared to dual-arm setups.

Conclusions:

• The single-arm interferometer is effective for precise optical metrology.
• The developed system offers improved stability and compactness.
• Suitable for characterizing optically transparent materials with flat surfaces.