A Love Letter to Single Photons
Major
Physics
Submission Type
Oral Presentation
Area of Study or Work
Physics
Faculty Advisor
Gabe Spalding
Location
CNS E104
Start Date
4-11-2026 11:15 AM
End Date
4-11-2026 12:15 PM
Abstract
This work is motivated by the broader context of our innovative Quantum curriculum, which allows beginning, early on, with inexpensive student-built detectors. Photon counting experiments are rapidly becoming a staple of upper-level undergraduate quantum physics laboratories, enabling students to explore Poisson statistics, photon bunching, and single-photon avalanche diode (SPAD) breakdown as a measurement technique. Many such experiments require physics departments to invest in expensive commercial SPAD modules that are highly sensitive. These devices offer excellent performance, but they are fragile as well as costly, and so their use can be intimidating to earlier-stage undergraduates. At IWU we extend the curriculum to offer scaffold related concepts and technical competencies to earlier-stage undergraduates: makeshift SPADs, constructed from less efficient reverse biased LEDs and basic breadboard components, offer a simple and inexpensive way to introduce key concepts to first- and second-year students. The construction and troubleshooting of a breadboard SPAD circuit is also a valuable exercise in building competence with electronics, including high-speed signal measurement, amplification, digitization, and microcontroller processing. However, not just any LED will work; most models fail catastrophically if reverse biased near breakdown, and the specific LED models initially used in our curriculum are no longer manufactured. To address this issue, we investigate whether specific modern surface-mount device (SMD) versions can serve as effective replacements. Our goals are to maintain or improve the performance of the original detectors, preserve the hands-on electronics experience central to the lab, and ensure that such experiments remain affordably accessible.
A Love Letter to Single Photons
CNS E104
This work is motivated by the broader context of our innovative Quantum curriculum, which allows beginning, early on, with inexpensive student-built detectors. Photon counting experiments are rapidly becoming a staple of upper-level undergraduate quantum physics laboratories, enabling students to explore Poisson statistics, photon bunching, and single-photon avalanche diode (SPAD) breakdown as a measurement technique. Many such experiments require physics departments to invest in expensive commercial SPAD modules that are highly sensitive. These devices offer excellent performance, but they are fragile as well as costly, and so their use can be intimidating to earlier-stage undergraduates. At IWU we extend the curriculum to offer scaffold related concepts and technical competencies to earlier-stage undergraduates: makeshift SPADs, constructed from less efficient reverse biased LEDs and basic breadboard components, offer a simple and inexpensive way to introduce key concepts to first- and second-year students. The construction and troubleshooting of a breadboard SPAD circuit is also a valuable exercise in building competence with electronics, including high-speed signal measurement, amplification, digitization, and microcontroller processing. However, not just any LED will work; most models fail catastrophically if reverse biased near breakdown, and the specific LED models initially used in our curriculum are no longer manufactured. To address this issue, we investigate whether specific modern surface-mount device (SMD) versions can serve as effective replacements. Our goals are to maintain or improve the performance of the original detectors, preserve the hands-on electronics experience central to the lab, and ensure that such experiments remain affordably accessible.