Development of Snapshot Imaging Spectrometer Using High-Density 3D-Printed Waveguide Arrays

Snapshot imaging spectrometers simultaneously capture spatial and spectral information, enabling applications in fields such as biomedical imaging and environmental monitoring. However, traditional designs often struggle to balance spatial-spectral sampling density with compactness, and their fabrication is typically complex, time-consuming, and reliant on bulky optical components. This thesis presents the development of two generations of miniaturized, waveguide-based imaging spectrometers fabricated using two-photon polymerization (2PP), a high-precision additive manufacturing technique. The first-generation system demonstrates the feasibility of 3D-printed optical fiber arrays for spectral imaging, featuring a 40×80 array of air-cladded fibers with engineered void spaces for dispersion. This structure achieves efficient spectral sampling through a prism-based system and is validated using resolution targets and spectral imaging of multi-color samples. Building on this foundation, the second generation which is a cladded structure utilizing complete straight waveguides with the angled end-face, achieves groundbreaking miniaturization and sampling of 3D-printed waveguide structure with a 26,000-waveguide array featuring a 4 µm pitch, 2.5 µm core size, and vertical layer height variations of 32 µm to distribute spectral sampling across 40 pixels. The compact structure (852 µm × 552 µm × 4093 µm) offers new opportunities for integrating snapshot spectroscopy into portable devices while maintaining high performance, as evidenced by spectral and spatial resolution, crosstalk, as well as throughput measurements. Validation with the biological microscopic samples underscores its utility in real-world applications. These advancements demonstrate the scalability and versatility of 2PP-based fabrication in addressing the limitations of conventional spectrometers, paving the way for more compact and integrated spectroscopy solutions.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Engineering

Grantor

Rice University

Year dc:date.issued

2025

Author dc:creator

• Cao, Haimu

Committee members dc:contributor.committeemember

• Tkaczyk, Tomasz
• Veeraraghavan, Ashok
• Lou, Jun

• Waveguide
• Snapshot Imaging Spectrometer

Statement dc:rights

• Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1911/118513

OAI identifier oai:identifier

oai:repository.rice.edu:1911/118513