35 research outputs found
Fabrication of optical planar waveguides in by He-ion implantation
In this paper, planar waveguides produced by He-ion implantation have been demonstrated in undoped and Yb-doped KY(WO/sub 4/)/sub 2/ crystals. The effective refractive indices of guided modes in surface planar waveguides were measured by dark m-line spectroscopy and the refractive index profiles were reconstructed by calculations based on the inverse WKB method. The end-faces of implanted crystals were polished and the waveguiding properties of the obtained planar structures were investigated using a laser diode at 980 nm and a CCD camera
Fabrication of optical planar and channel waveguides in Yb<sup>3+</sup> doped KY(WO<sub>4</sub>)<sub>2</sub> by He-ion implantation
Light ion implantation can be regarded as a universal tool for fabricating low-loss waveguide structures in optically active oxide materials. We have fabricated planar optical waveguides in :(2%) crystals by implanting He+ ions at 1.5 MeV, with doses ranging from 1 to 3x10^16 ions/cm2. An optical barrier with a decreased effective refractive index was created at the end of the ions' tracks, situated approximately 3.5 ÎĽm below the surface. The change in refractive index with respect to the bulk value and its stability to thermal treatment were investigated by dark m-line spectroscopy. Surface channel waveguides were obtained by writing sidewalls into the planar guiding layer by implantation through a slit. The sidewalls were produced by keeping the ion energy fixed and varying the incident angle of implantation. Channel waveguides of 5-ÎĽm width and 4-ÎĽm depth were obtained in the regions between the implanted sidewalls. Beam-propagation parameters were measured by investigating the output profile of end-coupled, fundamental-mode laser light at 980 nm. The results of loss measurements will be presented at the conference
Amplitude and phase modulation of time-energy entangled two-photon states
We experimentally demonstrate amplitude and phase modulation of a time-energy
entangled two-photon wave function. The entangled photons are produced by
spontaneous parametric down-conversion, spectrally dispersed in an prism
compressor, modulated in amplitude and/or phase, and detected in coincidence by
sum-frequency generation. First, we present a Fourier optical analysis of the
optical setup yielding an analytic expression for the resulting field
distribution at the exit plane of the shaping apparatus. We then introduce
amplitude and/or phase shaping and present results which can only be obtained
through a combination of the two. Specifically, we use a shaper-based
interferometer to measure the two-photon interference of an almost
bandwidth-limited two-photon wave function.Comment: 7 pages, 4 figure