Inspection of commercial optical devices for data storage using a three Gaussian beam microscope interferometer

Area of Science:

• Optical metrology
• Surface characterization
• Data storage technology

Background:

• Interferometric profilometry is crucial for characterizing optical surfaces.
• Existing methods may lack the required resolution or sensitivity for advanced data storage media.
• Microscope interferometers offer high precision but require specific adaptations for diverse surfaces.

Purpose of the Study:

• To evaluate a three Gaussian beam interferometer for profiling optical data storage surfaces.
• To assess the interferometer's capability in measuring compact disk (CD-R) and digital versatile disk (DVD-R) profiles.
• To demonstrate the suitability of this technique for quality control in optical data storage manufacturing.

Main Methods:

• Utilized a heterodyning three Gaussian beam interferometer for surface profiling.
• Performed one-dimensional radial scans on CD-R and DVD-R surfaces without data marks.
• Employed narrowband detection and signal filtering for enhanced measurement sensitivity and accuracy.

Main Results:

• Successfully measured the surface profiles of CD-R and DVD-R media.
• Obtained high vertical and lateral resolution (near lambda) measurements.
• Demonstrated that the output voltage signal amplitude is proportional to the surface's local vertical height.

Conclusions:

• The three Gaussian beam interferometer provides valuable information on track profiles of optical storage devices.
• Its high sensitivity and resolution make it an effective tool for quality control.
• This technique is well-suited for characterizing polycarbonate layers in data storage media.