  A search for laser light from Proxima Centauri was performed, including 107
high-resolution, optical spectra obtained between 2004 and 2019. Among them, 57
spectra contain multiple, confined spectral combs, each consisting of 10
closely-spaced frequencies of light. The spectral combs, as entities, are
themselves equally spaced with a frequency separation of 5800 GHz, rendering
them unambiguously technological in origin. However, the combs do not originate
at Proxima Centauri. Otherwise, the 107 spectra of Proxima Centauri show no
evidence of technological signals, including 29 observations between March and
July 2019 when the candidate technological radio signal, BLC1, was captured by
Breakthrough Listen. This search would have revealed lasers pointed toward
Earth having a power of 20 to 120 kilowatts and located within the 1.3au field
of view centered on Proxima Centauri, assuming a benchmark laser launcher
having a 10-meter aperture.
