Carlota Canalias

Nanoscale imaging of domains and domain walls in periodically poled ferroelectrics using atomic force microscopy

We use the inverse piezoelectric effect for high-resolution imaging of artificially produced ferroelectric domains in periodically poled potassium titanium phosphate, KTiOPO4, and lithium niobate, ...

Bright, single-spatial-mode source of frequency non-degenerate, polarization-entangled photon pairs using periodically poled KTP

We use two perpendicular crystals of periodically-poled KTP to directly generate polarization-entangled photon pairs, the majority of which are emitted into a single Gaussian spatial mode. The signal and idler photons have wavelengths of 810 nm and 1550 nm, respectively, and the photon-pair generation rate is 1.2x107 sec-1 for a pump power of 62 mW. The apparatus is compact, flexible, and easily to use.

Backward quasi-phase-matched second-harmonic generation in submicrometer periodically poled flux-grown KTiOPO4

A 1 turn thick flux-grown KTiOPO4 sample was poled with a 720 nm domain period by employing deep-UV laser lithography, chemical patterning, and electric field poling. An atomic force microscope was ...

5 mm thick periodically poled Rb-doped KTP for high energy optical parametric frequency conversion

A 5 mm thick periodically poled bulk Rb-doped KTiOPO4 (KTP) crystal with a period of 38.86 μm was fabricated by electric field poling. Chemical etching and optical evaluation show a high quality of ...

High-power, continuous-wave, second-harmonic generation at 532 nm in periodically poled KTiOPO 4

We report efficient generation of high-power, cw, single-frequency radiation in the green in a simple, compact configuration based on single-pass, second-harmonic generation of a cw ytterbium fiber laser at 1064 nm in periodically poled KTiOPO(4). Using a crystal containing a 17 mm single grating with period of 9.01 microm, we generate 6.2 W of cw radiation at 532 nm for a fundamental power of 29.75 W at a single-pass conversion efficiency of 20.8%. Over the entire range of pump powers, the generated green output is single frequency with a linewidth of 8.5 MHz and has a TEM(00) spatial profile with M(2)<1.34. The demonstrated green power can be further improved by proper thermal management of crystal heating effects at higher pump powers and also by optimized design of the grating period to include thermal issues.

Submicron periodically poled flux-grown KTiOPO4

A submicron domain grating has been created in a bulk ferroelectric. Electron-beam lithography and electric-field poling were used to fabricate the 800 nm period grating in a 0.5-mm-thick flux-grow ...

Polarization-switching characteristics of flux-grown KTiOPO4 and RbTiOPO4 at room temperature

A study of polarization-switching characteristics under an applied electrical field at room temperature is presented for flux-grown KTiOPO4 and RbTiOPO4. By optimizing the experimental conditions, ...

Highly efficient stimulated Raman scattering of picosecond pulses in KTiOPO4

High-efficiency picosecond stimulated Raman scattering (SRS) by phonon-polaritons has been observed in KTiOPO4 in a single pass through a 10mm long crystal. For pulses longer than 10ps, the SRS waves formed a symmetric pattern consisting of four distinct beams: SRS Stokes and anti-Stokes wavelengths originating both from the near-infrared pump and from the scattering of the second harmonic of the pump. At peak intensities above 10GW∕cm2 and pulse length of 1.5ps, the SRS character changes into what can be called “runaway” Raman scattering with efficiencies exceeding 50% and Raman gain spreading over 60THz.

Ferroelectric Domain Wall Injection

Ferroelectric domain wall injection has been demonstrated by engineering of the local electric field, using focused ion beam milled defects in thin single crystal lamellae of KTiOPO4 (KTP). The electric field distribution (top) displays localized field hot-spots, which correlate with nucleation events (bottom). Designed local field variations can also dictate subsequent domain wall mobility, demonstrating a new paradigm in ferroelectric domain wall control.

Frequency-doubling in femtosecond laser inscribed periodically-poled potassium titanyl phosphate waveguides

Frequency doubling has been achieved in femtosecond-laser-inscribed single-mode waveguides written in two periodically-poled potassium titanyl phosphate crystals. A conversion efficiency of 0.22 %W(1) was obtained for first-order quasi-phase matching at 980 nm and an efficiency of 0.02 %W(-1) for third-order quasi-phase matching at 800 nm.