Spectral Response Pixels in Lithium Niobate for Spectroscopic Applications

Area of Science:

• Materials Science
• Optical Engineering
• Spectroscopy

Background:

• Miniaturized spectroscopic systems are crucial for field-deployable and wearable applications.
• Current spectral encoding units face challenges in manufacturability, stability, and bandwidth during miniaturization.
• There is a need for robust, compact, and high-performance spectral encoding solutions.

Purpose of the Study:

• To present a novel, single-step fabrication method for microscale spectral response pixels.
• To demonstrate the broad bandwidth, stability, and compact nature of these pixels.
• To explore their application potential in precise spectral detection and liveness recognition.

Main Methods:

• Utilized ultrafast laser-induced amorphous phase transition in lithium niobate crystals.
• Created pixelated structures enabling localized, frequency-dependent optical modulation.
• Characterized pixel performance across a broad spectral range (400-1550 nm) and viewing angles.

Main Results:

• Successfully inscribed ultra-compact (5 × 5 µm²) spectral response pixels.
• Achieved viewing angle independent operation with broad spectral bandwidth and high stability.
• Demonstrated potential for precise spectral detection and liveness recognition.

Conclusions:

• The single-step laser inscription method offers a versatile approach to fabricating robust micro-spectroscopic devices.
• These pixels overcome limitations of traditional spectral encoding units, enabling affordable and field-deployable solutions.
• The technology paves the way for advanced sensing, measuring, and imaging applications.