arXiv subjects

Joanna A. Zielinska

Publications and source records attributed to Joanna A. Zielinska.

6 recordsLinked to original sources

arXiv2025

Explaining Optomechanical Libration Spectra: A Stochastic Simulation Approach

We present a practical and computationally effective Ito-Taylor expansion based stochastic simulation framework for modeling rotational optomechanics experiments. By developing a model using this framework, we could capture the nonlinear orientation dynamics of an optically levitated, nearly cylindrically symmetric nanodumbbell. It successfully reproduces and explains shoulder-like features observed in the power spectral density of libration, which we show arising from the interplay between confined libration and thermally driven rotation around the particle symmetry axis.

physics.comp-ph↗

arXiv2024

Feedback cooling a levitated nanoparticle's libration to below 100 phonons

Macroscopic rotors are interesting model systems to test quantum theory and for quantum sensing. A promising approach for bringing these systems to the quantum regime is to combine sensitive detection with feedback cooling to reduce the thermal occupation of the mechanics. Here, we implement a backward-scattering scheme to efficiently detect all three libration modes of an optically levitated nanoparticle. We demonstrate parametric feedback cooling of all three libration degrees of freedom to below 16~mK, with one of the modes reaching the temperature of 1.3~mK, corresponding to a mean phonon number of 84. Finally, we characterize the backward-scattering scheme by determining its measurement efficiency to be 0.5\%.

quant-ph↗

arXiv2018

A self-tuning optical resonator

We demonstrate a nonlinear optical resonator that tunes itself onto resonance with an input beam. In a monolithic Fabry-Perot cavity implemented in rubidium-doped periodically-poled potassium titanyl phosphate, an intensity-dependent refractive index produces line-pulling by multiple free-spectral ranges (FSRs). In this condition, the cavity passively maintains optical resonance in the face of FSR-scale excursions of the drive laser frequency: when one resonant operating-point becomes unstable, the resonator rapidly transitions to another resonant operating point. We demonstrate stable second-harmonic generation with no active feedback to laser or cavity. The self-tuning effect appears to be supported by a very strong, previously unreported optical nonlinearity.

physics.optics↗

arXiv2018

Atom-resonant squeezed light from a tunable monolithic ppRKTP parametric amplifier

We demonstrate vacuum squeezing at the D1 line of atomic rubidium (795 nm) with a tunable, doubly-resonant, monolithic sub-threshold optical parametric oscillator in periodically-poled Rb-doped potassium titanyl phosphate. The squeezing appears to be undiminished by a strong dispersive optical nonlinearity recently observed in this material.

quant-ph↗

arXiv2016

Fully-resonant, tunable, monolithic frequency conversion as a coherent UVA source

We demonstrate a monolithic frequency converter incorporating up to four tuning degrees of freedom, three temperature and one strain, allowing resonance of pump and generated wavelengths simultaneous with optimal phase-matching. With a Rb-doped periodically-poled potassium titanyl phosphate (KTP) implementation, we demonstrate efficient continuous-wave second harmonic generation from 795 nm to 397 nm, with low-power efficiency of 72%/W and high-power slope efficiency of 4.5%. The measured performance shows good agreement with theoretical modeling of the device. We measure optical bistability effects, and show how they can be used to improve the stability of the output against pump frequency and amplitude variations.

physics.optics↗

arXiv2014

A macroscopic quantum state analysed particle by particle

Explaining how microscopic entities collectively produce macroscopic phenomena is a fundamental goal of many-body physics. Theory predicts that large-scale entanglement is responsible for exotic macroscopic phenomena, but observation of entangled particles in naturally occurring systems is extremely challenging. Synthetic quantum systems made of atoms in optical lattices have been con- structed with the goal of observing macroscopic quantum phenomena with single-atom resolution. Serious challenges remain in producing and detecting long-range quantum correlations in these systems, however. Here we exploit the strengths of photonic technology, including high coherence and efficient single-particle detection, to study the predicted large-scale entanglement underlying the macroscopic quantum phenomenon of polarization squeezing. We generate a polarization-squeezed beam, extract photon pairs at random, and make a tomographic reconstruction of their joint quantum state. We present experimental evidence showing that all photons arriving within the squeezing coherence time are entangled, that entanglement monogamy dilutes entanglement with increasing photon density and that, counterintuitively, increased squeezing can reduce bipartite entanglement. The results provide direct evidence for entanglement of macroscopic numbers of particles and introduce micro-analysis to the study of macroscopic quantum phenomena.

quant-ph↗