Pulsed Laser as a Continuous Particle Stream

TL;DR

This paper reinterprets pulsed laser operation using a particle-based view of light, showing that mode-locked lasers produce a continuous photon stream with bright and dark states, aligning theory with experimental pulse timing.

Contribution

It introduces a particle-based quantum mechanical framework for understanding pulsed lasers, eliminating the need for wave superposition in pulse shaping explanations.

Findings

Dark states dominate multimode interference in pulsed lasers.

Mode-locked lasers produce a continuous photon beam with bright and dark states.

Theoretical bright-to-dark state ratio matches experimental pulse-to-interval ratio.

Abstract

With the recently introduced particle interpretation of the double-slit experiment for light fields [Phys. Rev. Lett. 134, 13360 (2025)], all related interference phenomena can be reinterpreted in terms of light particle states that either couple (bright) or do not couple (dark) with detectors. Here, we apply this approach to multimode pulsed lasers, unifying the description of their generation inside optical cavities and propagation outside them, now relying solely on quantum mechanics, i.e., without invoking wave superposition to explain pulse shaping. Specifically, we demonstrate that multimode interference presents a dominance of particle dark states over the bright ones and mode-locked pulsed lasers consist of a continuous photon beam, with photons forming bright states during pulses and dark states in between. Additionally, we analyze mode-locked pulsed lasers, showing that the theoretical bright-to-dark state ratio matches the experimental pulse-to-interval duration ratio.