Optical fiber speckle spectrometer based on reversed-lens smartphone microscope

Area of Science:

• Optical Physics
• Spectroscopy
• Mobile Technology

Background:

• Smartphones offer a versatile platform for developing portable scientific instruments.
• Traditional spectroscopy methods often rely on bulky and expensive components like diffraction gratings.

Purpose of the Study:

• To demonstrate the feasibility of speckle spectroscopy using smartphone hardware.
• To develop a mobile application for rapid spectral analysis.
• To achieve performance exceeding traditional diffraction gratings.

Main Methods:

• Light was coupled into an optical fiber.
• Emergent speckle patterns were imaged using a smartphone camera with a reversed lens.
• A mobile computing app processed speckle patterns to reconstruct spectra.
• A tunable source generated visible-wavelength spectra (470-670 nm) for testing.

Main Results:

• Speckle spectroscopy was successfully demonstrated using smartphone components.
• The system accurately reconstructed single and multi-peaked spectra.
• The technique determined spectra in under one second.
• Metameric spectral pairs were distinguished, showcasing high resolution.

Conclusions:

• Smartphone-based speckle spectroscopy is a viable and high-performance technique.
• This approach provides a portable, rapid, and cost-effective alternative to conventional spectroscopy.
• The developed mobile application enables on-the-spot spectral analysis.