Rotational frequency shiftof a light beam

D. Courtial, D. A. Robertson, K. Dholakia, L. Allen, M. J. Padgett

Research output: Contribution to journalArticle

221 Citations (Scopus)


We explain the rotational frequency shift of a light beam in classical terms and measure it using a mm-wave source. The shift is equal to the total angular momentum per photon multiplied by the angular velocity between the source and observer. This is analogous to the translational Doppler shift, which is equal to the momentum per photon multiplied by the translational velocity. We show that the shifts due to the spin and orbital angular momentum components of the light beam act in an additive way.

Original languageEnglish
Pages (from-to)4828-4830
Number of pages3
JournalPhysical Review Letters
Issue number22
Publication statusPublished - 1998 Nov 30


All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Courtial, D., Robertson, D. A., Dholakia, K., Allen, L., & Padgett, M. J. (1998). Rotational frequency shiftof a light beam. Physical Review Letters, 81(22), 4828-4830.