Optical Imaging of Blu-ray Disc Nanostructures

Blu-ray discs contain one of the most challenging nanostructures routinely manufactured at scale:~100 nm wide lines with ~200 nm pitch.

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These dimensions are below the classical resolution limit of conventional optical microscopes, which is why Blu-ray tracks are traditionally visualised using:

• Scanning Electron Microscopy (SEM)

• Near-field or contact-based super-resolution techniques

• Microsphere imaging, which requires the optical element to be almost in physical contact with the sample

Until now, purely optical far-field imaging of Blu-ray tracks has not been possible with a standard microscope objective.

What Makes This Application Unique

The Mounted LEDs diffraction-limited objective lens enables direct optical visualisation of Blu-ray tracks using a standard optical microscope: no electrons, no probes, no near-contact optics.

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This is achieved with:

• True diffraction-limited performance

• Oil immersion

• A working distance of 230 µm

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Unlike microsphere-based super-resolution methods which rely on near-field coupling and operate at near-zero working distance — this lens maintains a macroscopic, usable working distance, while still resolving structures traditionally considered “optically invisible”.

Why Conventional Optical Objectives Fail

In classical optical microscopy, lateral resolution is limited by diffraction to approximately ~200 nm in the visible spectrum, even with high numerical aperture objectives.

As a result:

• 100 nm lines blur together

• Track edges cannot be distinguished

• Contrast collapses into a uniform grey pattern

This is why Blu-ray structures are commonly shown only in SEM images in textbooks and datasheets.