2 research outputs found
Giant photoelasticity of polaritons for detection of coherent phonons in a superlattice with quantum sensitivity
The functionality of phonon-based quantum devices largely depends on the
efficiency of interaction of phonons with other excitations. For phonon
frequencies above 20 GHz, generation and detection of the phonon quanta can be
monitored through photons. The photon-phonon interaction can be enormously
strengthened by involving an intermediate resonant quasiparticle, e.g. an
exciton, with which a photon forms a polariton. In this work, we discover a
giant photoelasticity of exciton-polaritons in a short-period superlattice and
exploit it for detecting propagating acoustic phonons. We demonstrate that 42
GHz coherent phonons can be detected with extremely high sensitivity in the
time domain Brillouin oscillations by probing with photons in the spectral
vicinity of the polariton resonance.Comment: 6 pages, 3 figures, Supplemental Material
Resonant thermal energy transfer to magnons in a ferromagnetic nanolayer
Energy harvesting is a concept which makes dissipated heat useful by transferring thermal energy to other excitations. Most of the existing principles are realized in systems which are heated continuously. We present the concept of high-frequency energy harvesting where the dissipated heat in a sample excites resonant magnons in a thin ferromagnetic metal layer. The sample is excited by femtosecond laser pulses with a repetition rate of 10 GHz which results in temperature modulation at the same frequency with amplitude ~0.1 K. The alternating temperature excites magnons in the ferromagnetic nanolayer which are detected by measuring the net magnetization precession. When the magnon frequency is brought onto resonance with the optical excitation, a 12-fold increase of the amplitude of precession indicates efficient resonant heat transfer from the lattice to coherent magnons. The demonstrated principle may be used for energy harvesting in various nanodevices operating at GHz and sub-THz frequency ranges