1. A snapshot spectral domain optical coherence tomographer comprising: a. a light source providing a plurality of beamlets; b. a beam splitter splitting the plurality of beamlets into a reference arm and a sample arm; c. a first optical system that projects the sample arm onto multiple locations of the sample; d. a second optical system for collection of a plurality of reflected sample beamlets; e. a third optical system projecting the reference arm onto a reflecting surface and receiving a plurality of reflected reference beamlets; f. a parallel interferometer that provides a plurality of interferograms from each of the plurality of sample beamlets with each of the plurality of reference beamlets; g. an optical image mapper configured to spatially separate the beamlets; h. a spectrometer configured to disperse each of the interferograms into its respective spectral components and project the spectral components of each interferogram in parallel; and i. a photodetector configured to receive the spectral components of each interferogram and provide in parallel photon quantification.