Buried Dielectric PCSEL: A Leap Forward in Eye-Safe Laser Technology

Imagine a laser that is powerful, compact, and safe for the eyes—now picture it operating at room temperature using cutting-edge buried-dielectric photonic-crystal technology. That is precisely what researchers from the University of Illinois Urbana-Champaign have achieved, marking a breakthrough in semiconductor laser design with wide-ranging applications in sensing, defense, and beyond.

What Are PCSELs?

Photonic-crystal surface-emitting lasers (PCSELs) are a class of semiconductor lasers that combine high brightness with exceptionally precise, narrow, and round beam profiles. Their key differentiator is a photonic crystal layer integrated into the laser cavity, which enables precise control of light emission and beam shape.

PCSELs offer superior beam quality over traditional semiconductor lasers, making them especially valuable in applications such as LiDAR, free-space optical communications, and industrial material processing.

The Breakthrough

A team led by Professor Kent Choquette demonstrated the first-ever photopumped lasing from a buried dielectric PCSEL at room temperature, operating at eye-safe wavelengths (~1.5 µm). This scientific research, published at IEEE Photonics Journal, directly addresses key challenges in PCSEL fabrication, potentially setting the stage for industrial adoption.

Three-dimensional sketch of a buried dielectric photonic-crystal surface-emitting laser (PCSEL) with cutaway revealing the buried dielectric photonic crystal layer, not to scale. The red circle represents photopumping with a 980-nm beam, and the arrow represents the measured 1.5-um vertical emission (Photopumped Buried Dielectric Photonic-Crystal Surface-Emitting Lasers, 2025).

Key Innovation: Buried Dielectric PCSEL

Traditional PCSELs use air holes etched into the photonic crystal layer during fabrication. However, these air voids can deform or fill during semiconductor regrowth, distorting the photonic structure and compromising performance.

The Illinois team replaced the air holes with amorphous silicon dioxide (SiO₂) features, deposited using a chemical vapor deposition (CVD) process. This SiO₂ was embedded within the photonic crystal layer—a buried dielectric—during molecular beam epitaxy (MBE) regrowth on an indium phosphide (InP) substrate. The process required precise lateral overgrowth to seamlessly integrate the amorphous dielectric into the crystalline semiconductor without introducing defects.

Graduate student Erin Raftery, lead author of the study, explained: “We were actually able to grow laterally around the dielectric material and coalesce on top.”

Why This Matters

• Improved structural stability: SiO₂ features are more robust than air voids, maintaining photonic structure integrity during and after regrowth.

• Eye-safe operation: The ~1.5 µm wavelength is suitable for applications where human eye safety is critical.

• Path toward industrialization: Stable photonic structures at room temperature open the door for scalable, electrically driven devices.

Potential Applications

• Defense and military sensing: Secure, eye-safe LiDAR for battlefield mapping, surveillance, and target acquisition.

• Autonomous navigation: High-precision LiDAR for vehicles, drones, and robotics.

• Industrial and medical: Laser machining, metrology, and specialized diagnostic imaging.

What’s Next

The research team plans to integrate electrical contacts into the buried dielectric PCSELs, enabling electrically pumped operation—an important step toward commercial devices. Collaborative work between the Choquette group, Minjoo Larry Lee’s lab, and the Air Force Research Laboratory will continue driving the technology toward practical use.

This buried dielectric PCSEL is a major step toward robust, high-performance, eye-safe lasers that can operate at room temperature. With its potential impact on defense, autonomous systems, and precision manufacturing, it stands as a powerful example of how fundamental research can shape future technology.

As a trusted partner to scientific research and technology developers, MSE Supplies supports innovations like this by providing high-quality InP and other semiconductor substrates, CVD coating systems, and a full range of optical materials, fabrication and characterization tools. These capabilities help ensure that groundbreaking concepts—like the buried dielectric PCSEL—can move from lab-scale demonstrations to industrial reality.

If you’re advancing research in materials science, photonics, semiconductor production, or laser technology, MSE Supplies can help equip your lab with the materials and tools needed to push boundaries. Explore our substrate offerings, coating equipments, and advanced fabrication equipment, or contact us directly to discuss your specific project requirements. Let’s work together to turn innovative ideas into tomorrow’s industry-changing solutions.

Sources:

1. Photopumped buried dielectric Photonic-Crystal Surface-Emitting lasers. (2025, June 1). IEEE Journals & Magazine | IEEE Xplore. Retrieved August 15, 2025, from https://ieeexplore.ieee.org/document/10965337

2. Grainger Engineering Office of Marketing and Communications. (n.d.-b). New research expands laser technology. Holonyak Micro & Nanotechnology Lab | Illinois. Retrieved August 15, 2025, from https://hmntl.illinois.edu/news/new-research-expands-laser-technology