389 research outputs found
Sensing Coherent Phonons with Two-photon Interference
Detecting coherent phonons pose different challenges compared to coherent
photons due to the much stronger interaction between phonons and matter. This
is especially true for high frequency heat carrying phonons, which are
intrinsic lattice vibrations experiencing many decoherence events with the
environment, and are thus generally assumed to be incoherent. Two photon
interference techniques, especially coherent population trapping (CPT) and
electromagnetically induced transparency (EIT), have led to extremely sensitive
detection, spectroscopy and metrology. Here, we propose the use of two photon
interference in a three level system to sense coherent phonons. Unlike prior
works which have treated phonon coupling as damping, we account for coherent
phonon coupling using a full quantum-mechanical treatment. We observe strong
asymmetry in absorption spectrum in CPT and negative dispersion in EIT
susceptibility in the presence of coherent phonon coupling which cannot be
accounted for if only pure phonon damping is considered. Our proposal has
application in sensing heat carrying coherent phonons effects and understanding
coherent bosonic multi-pathway interference effects in three coupled oscillator
systems
Axial plane optical microscopy.
We present axial plane optical microscopy (APOM) that can, in contrast to conventional microscopy, directly image a sample's cross-section parallel to the optical axis of an objective lens without scanning. APOM combined with conventional microscopy simultaneously provides two orthogonal images of a 3D sample. More importantly, APOM uses only a single lens near the sample to achieve selective-plane illumination microscopy, as we demonstrated by three-dimensional (3D) imaging of fluorescent pollens and brain slices. This technique allows fast, high-contrast, and convenient 3D imaging of structures that are hundreds of microns beneath the surfaces of large biological tissues
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