High-resolution compact spectrometer based on a custom-printed varied-line-spacing concave blazed grating

Area of Science:

• Optics and Photonics
• Spectroscopy
• Nanotechnology

Background:

• Compact spectrometers are crucial for portable spectroscopic analysis.
• Existing designs often face trade-offs between resolution, size, and efficiency.
• Varied-line-space (VLS) gratings offer potential for improved optical performance.

Purpose of the Study:

• To design, model, and characterize a highly compact spectrometer with superior resolution.
• To leverage a custom-designed VLS concave blazed grating for enhanced performance.
• To minimize the overall footprint of the spectrometer system.

Main Methods:

• Parametric modeling to link VLS grating design parameters with system performance and footprint.
• ZEMAX simulations to predict and confirm spectrometer resolution and performance enhancements.
• Vacuum nanoimprinting fabrication of the VLS grating using a non-uniformly expanded PDMS stamp.

Main Results:

• Achieved spectral resolution better than 1.5 nm (1.46 nm) across the 360-825 nm visible spectrum.
• Demonstrated a 15% resolution enhancement compared to constant line-space (CLS) gratings via simulation.
• Fabricated VLS grating exhibits 43% absolute diffraction efficiency, exceeding typical holographic gratings.

Conclusions:

• The developed compact spectrometer, featuring a single VLS concave blazed grating, offers unprecedented resolution and miniaturization.
• The VLS grating design and nanoimprinting fabrication method are effective for creating high-performance compact optical systems.
• This technology enables highly portable and powerful spectroscopic solutions.