Simona Mosca - Academia.edu (original) (raw)

Papers by Simona Mosca

Frontiers in Optics 2017, 2017

We experimentally demonstrate that optical frequency combs can be generated in a cw-pumped, nearl... more We experimentally demonstrate that optical frequency combs can be generated in a cw-pumped, nearly degenerate, doubly resonant optical parametric oscillator (OPO). Moreover, we present a time-domain theoretical model of the OPO and derive a non-instantaneous mean field dynamic equation for the parametric field. Numerical simulations of the mean field equation are in good agreement with the observed comb patterns.

Applied Sciences

Optical frequency comb synthesizers with a wide spectral range are an essential tool for many res... more Optical frequency comb synthesizers with a wide spectral range are an essential tool for many research areas such as spectroscopy, precision metrology, optical communication, and sensing. Recent studies have demonstrated the direct generation of frequency combs, via second-order processes, that are centered on two different spectral regions separated by an octave. Here, we present the capability of optical quadratic frequency combs for broad-bandwidth spectral emission in unexplored regimes. We consider comb formation under phase-matched conditions in a continuous-wave pumped singly resonant second-harmonic cavity, with large intracavity power and control of the detuning over several cavity linewidths. The spectral analysis reveals quite distinctive sidebands that arise far away from the pump, singularly or in a mixed regime together with narrowband frequency combs. Notably, by increasing the input power, the optical frequency lines evolve into widely spaced frequency clusters, and ...

Micromachines

Optical frequency combs are one of the most remarkable inventions in recent decades. Originally c... more Optical frequency combs are one of the most remarkable inventions in recent decades. Originally conceived as the spectral counterpart of the train of short pulses emitted by mode-locked lasers, frequency combs have also been subsequently generated in continuously pumped microresonators, through third-order parametric processes. Quite recently, direct generation of optical frequency combs has been demonstrated in continuous-wave laser-pumped optical resonators with a second-order nonlinear medium inside. Here, we present a concise introduction to such quadratic combs and the physical mechanism that underlies their formation. We mainly review our recent experimental and theoretical work on formation and dynamics of quadratic frequency combs. We experimentally demonstrated comb generation in two configurations: a cavity for second harmonic generation, where combs are generated both around the pump frequency and its second harmonic and a degenerate optical parametric oscillator, where c...

Quantum Sensing and Nano Electronics and Photonics XIV

Optical frequency combs currently represent enabling components in a wide number of fast-growing ... more Optical frequency combs currently represent enabling components in a wide number of fast-growing research fields, from frequency metrology to precision spectroscopy, from synchronization of telecommunication systems to environmental and biomedical spectrometry. As recently demonstrated, quadratic nonlinear media are a promising platform for optical frequency combs generation, through the onset of an internally pumped optical parametric oscillator in cavity enhanced second-harmonic generation systems. We present here a proposal for quadratic frequency comb generation in AlGaAs waveguide resonators. Based on the crystal symmetry properties of the AlGaAs material, quasi-phase matching can be realized in curved geometries (directional quasi-phase matching), thus ensuring efficient optical frequency conversion. We propose a novel design of AlGaAs waveguide resonators with strongly reduced total losses, compatible with long-path, high-quality resonators. By means of a numerical study, we predict efficient frequency comb generation with threshold powers in the microwatt range, paving the way for the full integration of frequency comb synthesizers in photonic circuits.

Journal of the Optical Society of America B

Quantum Information and Measurement (QIM) 2017, 2017

Phys. Chem. Chem. Phys., 2016

We demonstrate continuous-wave cavity ring-down spectroscopy of a partially hydrodynamic molecula... more We demonstrate continuous-wave cavity ring-down spectroscopy of a partially hydrodynamic molecular beam emerging from a buffer-gas-cooling source.

Nanophotonics, 2016

Quadratic nonlinear processes are currently exploited for frequency comb transfer and extension f... more Quadratic nonlinear processes are currently exploited for frequency comb transfer and extension from the visible and near infrared regions to other spectral ranges where direct comb generation cannot be accomplished. However, frequency comb generation has been directly observed in continuously pumped quadratic nonlinear crystals placed inside an optical cavity. At the same time, an introductory theoretical description of the phenomenon has been provided, showing a remarkable analogy with the dynamics of third-order Kerr microresonators. Here, we give an overview of our recent work on χ

Physical Review A, 2015

We experimentally demonstrate and theoretically explain the onset of optical frequency combs in a... more We experimentally demonstrate and theoretically explain the onset of optical frequency combs in a simple cavity-enhanced second-harmonic-generation system, exploiting second-order nonlinear interactions. Two combs are simultaneously generated around the fundamental pump frequency, with a spectral bandwidth up to about 10 nm, and its second harmonic. We observe different regimes of generation, depending on the phase-matching condition for second-harmonic-generation. Moreover, we develop an elemental model which provides a deep physical insight into the observed dynamics. Despite the different underlying physical mechanism, the proposed model is remarkably similar to the description of third-order effects in microresonators, revealing a potential variety of new effects to be explored and laying the groundwork for a novel class of highly efficient and versatile frequency comb synthesizers based on second-order nonlinear materials.

Nonlinear Optics and Applications VI, 2012

ABSTRACT We present a widely-tunable, singly-resonant optical parametric oscillator, emitting mor... more ABSTRACT We present a widely-tunable, singly-resonant optical parametric oscillator, emitting more than 1 W in the region between 2.7 and 4.2 μm. Two configurations have been studied in order to improve the frequency stability and the linewidth of the OPO emission. First, we stabilized the signal frequency to a high-finesse Fabry-Perot cavity. Then, we locked both pump and signal frequency to the frequency comb generated by a NIR fs mode-locked fibre laser, linked to the caesium primary standard. With this last configuration we carried out saturation spectroscopy of several transitions belonging to the ν1 rovibrational band of CH3I, resolving their electronic quadrupole hyperfine structure, and determining the absolute frequency of the hyperfine components with a 50-kHz-uncertainty. An upper limit for the idler linewidth has been estimated as 200 kHz FWHM.

CLEO: 2014, 2014

ABSTRACT We present a transfer oscillator scheme between the pump and signal modes of a singly re... more ABSTRACT We present a transfer oscillator scheme between the pump and signal modes of a singly resonant optical parametric oscillator, emitting in the reange 2.7-4.2 μ m, demonstrating sub-kHz linewidth of the idler mode.

CLEO: 2013, 2013

ABSTRACT We demonstrate fast idler wave mode-hop-free tuning over ~30cm-1 around 3.3micron using ... more ABSTRACT We demonstrate fast idler wave mode-hop-free tuning over ~30cm-1 around 3.3micron using a cw ppMgCLN-OPO pumped near 1063nm, allowing to capture in a single pump scan at a rate up to 20nm/s the entire Q-branch of CH4 (3000-3025cm-1).

Optics Letters, 2013

We report on a widely (2.25 THz or 75 cm −1) and rapidly (4.5 THz∕s) mode-hop-free (MHF) tunable ... more We report on a widely (2.25 THz or 75 cm −1) and rapidly (4.5 THz∕s) mode-hop-free (MHF) tunable mid-IR laser source at ∼3.3 μm, consisting of a 5%-MgO:LiNbO 3 singly resonant optical parametric oscillator (SRO) pumped by an automated broadly MHF tunable extended-cavity diode laser (ECDL). The broad and rapid MHF tuning capability of the ECDL is readily transferred to the SRO idler wave owing to the quasi-noncritical pump spectral acceptance bandwidth of the quasi-phase-matching. Fast and broadband high-resolution Doppler spectroscopy measurements of the ν 3 band of CH 4 are presented to illustrate the performance of the mid-IR optical parametric oscillator spectrometer.

Optics Express, 2013

We report a thorough analysis of the spectral properties of an ytterbium-doped fibre amplifier, s... more We report a thorough analysis of the spectral properties of an ytterbium-doped fibre amplifier, seeded by a Nd:YAG laser, whose linewidth has been narrowed down to 1 Hz by locking the laser to an ultrastable reference cavity. We measured the phase noise contribution from the amplifier, showing that it does not depend on the amplification gain, nor on the seed laser linewidth. Moreover, the amplifier-induced phase noise does not affect the final linewidth, as verified by heterodyne linewidth measurement within the 0.2 Hz resolution bandwidth of our acquisition set-up. Preservation of spectral purity below Hz-level is promising for more demanding applications, from nonlinear optics to frequency/time-standard transfer over fibre links.

Nuclear Science, …, 2011

Seismic noise limits Earth based gravitational wave interferometric detectors at low frequencies.... more Seismic noise limits Earth based gravitational wave interferometric detectors at low frequencies. The detection threshold can be lowered down to a few Hz using a seismic attenuation system based on Inverted Pendulum (IP) which sustains interferometer optical ...