Single photons generated by spontaneous parametric down conversion are often utilized in heralded schemes, in which case the heralded photon purity must be maximized to preserve the indistinguishability of the photons that carry out quantum computing. In this work, we present software designed for accurate calculation of such purity, which was optimized to minimize computational resources and time, allowing for maximum purity searches in broad wavelength ranges. Lithium niobate and potassium titanyl phosphate (KTP) were studied in three phase-matching conditions, and an ultra-high purity configuration was found. The configuration was experimentally realized through an ion-exchanged KTP waveguide, exploiting flexibility in pump and phase matching temperature to compensate fabrication deviations, and purities as high as 0.923 were found, with very high generation rate of 40.7 MHz / mW. The experimental purity is significantly degraded by the multimode guiding at the desired wavelengths, which we propose to address by engineering with femtosecond laser writing, of which preliminary results are presented.
Simulation and demonstration of non-degenerate high purity biphoton state generation by SPDC in PPKTP
Barone A.;Bajoni D.;Liscidini M.;Galli M.;Osellame R.
2024-01-01
Abstract
Single photons generated by spontaneous parametric down conversion are often utilized in heralded schemes, in which case the heralded photon purity must be maximized to preserve the indistinguishability of the photons that carry out quantum computing. In this work, we present software designed for accurate calculation of such purity, which was optimized to minimize computational resources and time, allowing for maximum purity searches in broad wavelength ranges. Lithium niobate and potassium titanyl phosphate (KTP) were studied in three phase-matching conditions, and an ultra-high purity configuration was found. The configuration was experimentally realized through an ion-exchanged KTP waveguide, exploiting flexibility in pump and phase matching temperature to compensate fabrication deviations, and purities as high as 0.923 were found, with very high generation rate of 40.7 MHz / mW. The experimental purity is significantly degraded by the multimode guiding at the desired wavelengths, which we propose to address by engineering with femtosecond laser writing, of which preliminary results are presented.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
