Finite-difference time-domain simulation of thermal noise in open cavities

Jonathan Andreasen*, Hui Cao, Allen Taflove, Prem Kumar, Chang Qi Cao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


A numerical model based on the finite-difference time-domain (FDTD) method is developed to simulate thermal noise in open cavities owing to output coupling. The absorbing boundary of the FDTD grid is treated as a blackbody, whose thermal radiation penetrates the cavity in the grid. The calculated amount of thermal noise in a one-dimensional dielectric cavity recovers the standard result of the quantum Langevin equation in the Markovian regime. Our FDTD simulation also demonstrates that in the non-Markovian regime the buildup of the intracavity noise field depends on the ratio of the cavity photon lifetime to the coherence time of thermal radiation. The advantage of our numerical method is that the thermal noise is introduced in the time domain without prior knowledge of cavity modes.

Original languageEnglish (US)
Article number023810
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Issue number2
StatePublished - Feb 8 2008

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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