An all-fiber alternative for measuring luminescence

Conventional systems for measuring luminescence lifetime and spectra of glowing materials, like phosphorescent powders or fluorescent probes, are typically bulky and expensive. They also rely on free-space optics — wireless communication via lasers — that can be difficult to align and maintain.

Deng et al. developed a simple, low-cost, all-fiber system that uses off-the-shelf fiber-optic components to transmit both emitted luminescence and excitation light.

“It works much like how data travels through internet cables,” said author Xuewen Shu. “As far as we know, this is the first fully fiber-based, time-gated luminescence system that works without free-space optics or expensive high-speed detectors like intensified [charge-coupled device] cameras or single-photon counters.”

The setup uses a 450 nm laser diode as the excitation source and a fiber-optic switch as a fast shutter to control when the detector collects light. Two synchronized electrical signals with adjustable delay control the laser and the shutter. By varying the delay between excitation and detection, system users can time gate the measurement, effectively capturing luminescence snapshots at different moments after excitation. The snapshots can then be used to reconstruct the decay curve and extract the luminescence lifetime.

Since measuring many materials with millisecond-scale lifetimes does not require picosecond or nanosecond resolution, the system represents a practical and much more affordable alternative to those commonly used in traditional lab settings.

“This could help bring time-resolved luminescence measurements to real-world applications such as portable medical diagnostics, environmental oxygen monitoring, or even point-of-care testing,” said Shu. “Also, it is inherently flexible and can be easily integrated with other fiber-optic components or imaging systems. It’s a step toward making sophisticated optical measurements more accessible and user-friendly.”

Source: “All-fiber time-resolved detection system for measuring luminescence lifetime and spectra,” by Qisheng Deng, Lei Kong, Yulei Liu, Jintao Cai, Yi Zhou, Ming Shen, and Xuewen Shu, APL Photonics (2026). The article can be accessed at https://doi.org/10.1063/5.0344230 .