4 research outputs found
Acousto-optic and opto-acoustic modulation in piezo-optomechanical circuits
Acoustic wave devices provide a promising chip-scale platform for efficiently
coupling radio frequency (RF) and optical fields. Here, we use an integrated
piezo-optomechanical circuit platform that exploits both the piezoelectric and
photoelastic coupling mechanisms to link 2.4 GHz RF waves to 194 THz (1550 nm)
optical waves, through coupling to propagating and localized 2.4 GHz acoustic
waves. We demonstrate acousto-optic modulation, resonant in both the optical
and mechanical domains, in which waveforms encoded on the RF carrier are mapped
to the optical field. We also show opto-acoustic modulation, in which the
application of optical pulses gates the transmission of propagating acoustic
waves. The time-domain characteristics of this system under both pulsed RF and
pulsed optical excitation are considered in the context of the different
physical pathways involved in driving the acoustic waves, and modeled through
the coupled mode equations of cavity optomechanics.Comment: 8 pages, 6 figure
Efficient spectroscopy of single embedded emitters using optical fiber taper waveguides
A technique based on using optical fiber taper waveguides for probing single
emitters embedded in thin dielectric membranes is assessed through numerical
simulations. For an appropriate membrane geometry, photoluminescence collection
efficiencies in excess of 10 % are predicted, exceeding the efficiency of
standard free-space collection by an order of magnitude. Our results indicate
that these fiber taper waveguides offer excellent prospects for performing
efficient spectroscopy of single emitters embedded in thin films, such as a
single self-assembled quantum dot in a semiconductor membrane.Comment: Final published version Optics Express Vol. 17, p. 10542 (2009
Multifocus microscopy with precise color multi-phase diffractive optics applied in functional neuronal imaging
International audienceMultifocus microscopy (MFM) allows high-resolution instantaneous three-dimensional (3D) imaging and has been applied to study biological specimens ranging from single molecules inside cells nuclei to entire embryos. We here describe pattern designs and nanofabrication methods for diffractive optics that optimize the light-efficiency of the central optical component of MFM: the diffractive multifocus grating (MFG). We also implement a " precise color " MFM layout with MFGs tailored to individual fluorophores in separate optical arms. The reported advancements enable faster and brighter volumetric time-lapse imaging of biological samples. In live microscopy applications, photon budget is a critical parameter and light-efficiency must be optimized to obtain the fastest possible frame rate while minimizing photodamage. We provide comprehensive descriptions and code for designing diffractive optical devices, and a detailed methods description for nanofabrication of devices. Theoretical efficiencies of reported designs is ≈90% and we have obtained efficiencies of > 80% in MFGs of our own manufacture. We demonstrate the performance of a multi-phase MFG in 3D functional neuronal imaging in living C. elegans