Optica

Journal: Optica

Publisher

OSA Publishing

ISSN

2334-2536

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Publications 1 - 10 of 35

Evidence of linear chirp in mid-infrared quantum cascade lasers
Singleton, Matthew; Jouy, Pierre; Beck, Mattias; et al. (2018)
Optica
Towards on-chip photonic-assisted radio-frequency spectral measurement and monitoring
Romero Cortés, Luis; Onori, Daniel; de Chatellus, Hugues Guillet; et al. (2020)
Optica
Precise detection and monitoring of the frequency spectrum of microwave signals are essential to myriad scientific and technological disciplines, including both civil and defense areas, such as telecommunications, radar, biomedical instrumentation, radio astronomy, etc. Historically, microwave engineering has provided solutions for these tasks. However, current radio-frequency (RF) technologies suffer from inherent shortcomings that limit their capability to provide agile (e.g., real-time) measurements over a large operation bandwidth in energy-efficient and compact (e.g., integrated) formats. Overcoming these limitations is key to fulfilling pressing performance requirements in the above-mentioned application fields, as well as for compatibility with platforms that require chip-scale integration and/or low weight and dimensions, such as satellites and drones. Integrated microwave photonics is an emerging field that leverages the advantages of optical technologies for realization of microwave operations with high bandwidth, low power consumption, and increased agility and flexibility in on-chip platforms, offering an alternative path for integration of advanced RF processing and analysis methods in mature semiconductor technologies. This mini review surveys some of the latest advances in microwave spectral measurement and monitoring techniques realized through photonic approaches, with a special focus on methods suitable for on-chip integration.
High-power picosecond deep-UV source via group velocity matched frequency conversion
Willenberg, Benjamin; Brunner, Fabian; Phillips, Christopher R.; et al. (2020)
Optica
High-power 100 fs semiconductor disk lasers
Waldburger, Dominik; Link, Sandro M.; Mangold, Mario; et al. (2016)
Optica
Electro-optic interface for ultrasensitive intracavity electric field measurements at microwave and terahertz frequencies
Benea-Chelmus, Ileana-Cristina; Salamin, Yannick; Settembrini, Francesca Fabiana; et al. (2020)
Optica
Ultra-high-resolution software-defined photonic terahertz spectroscopy
Hermans, Rodolfo I.; Seddon, James; Shams, Haymen; et al. (2020)
Optica
A novel technique for high-resolution 1.5 µm photonics-enabled terahertz (THz) spectroscopy using software control of the illumination spectral line shape (SLS) is presented. The technique enhances the performance of a continuous-wave THz spectrometer to reveal previously inaccessible details of closely spaced spectral peaks. We demonstrate the technique by performing spectroscopy on LiYF4:Ho3+, a material of interest for quantum science and technology, where we discriminate between inhomogeneous Gaussian and homogeneous Lorentzian contributions to absorption lines near 0.2 THz. Ultra-high-resolution (<100 Hz full-width at half maximum) frequency-domain spectroscopy with quality factor Q > 2 × 109 is achieved using an exact frequency spacing comb source in the optical communications band, with a custom uni-traveling-carrier photodiode mixer and coherent down-conversion detection. Software-defined time-domain modulation of one of the comb lines is demonstrated and used to resolve the sample SLS and to obtain a magnetic field-free readout of the electronuclear spectrum for the Ho3+ ions in LiYF4:Ho3+. In particular, homogeneous and inhomogeneous contributions to the spectrum are readily separated. The experiment reveals previously unmeasured information regarding the hyperfine structure of the first excited state in the 5 I8 manifold complementing the results reported in Phys. Rev. B 94, 205132 (2016).
Energy-dependent photoemission delays from noble metal surfaces by attosecond interferometry
Locher, Reto; Castiglioni, Luca; Lucchini, Matteo; et al. (2015)
Optica
How quanta of energy and charge are transported on both atomic spatial and ultrafast timescales is at the heart of modern technology. Recent progress in ultrafast spectroscopy has allowed us to directly study the dynamical response of an electronic system to interaction with an electromagnetic field. Here, we present energy-dependent photoemission delays from the noble metal surfaces Ag(111) and Au(111). An interferometric technique based on attosecond pulse trains is applied simultaneously in a gas phase and a solid-state target to derive surface-specific photoemission delays. Experimental delays on the order of 100 as are in the same time range as those obtained from simulations. The strong variation of measured delays with excitation energy in Ag(111), which cannot be consistently explained invoking solely electron transport or initial state localization as supposed in previous work, indicates that final state effects play a key role in photoemission from solids.
Soft x-ray microscopy with 7 nm resolution
Rössner, Benedikt; Finizio, Simone; Koch, Frieder; et al. (2020)
Optica
The availability of intense soft x-ray beams with tunable energy and polarization has pushed the development of highly sensitive, element-specific, and noninvasive microscopy techniques to investigate condensed matter with high spatial and temporal resolution. The short wavelengths of soft x-rays promise to reach spatial resolutions in the deep single-digit nanometer regime, providing unprecedented access to magnetic phenomena at fundamental length scales. Despite considerable efforts in soft x-ray microscopy techniques, a two-dimensional resolution of 10 nm has not yet been surpassed in direct imaging. Here, we report on a significant step beyond this long-standing limit by combining newly developed soft x-ray Fresnel zone plate lenses with advanced precision in scanning control and careful optical design. With this approach, we achieve an image resolution of 7 nm. By combining this highly precise microscopy technique with the x-ray magnetic circular dichroism effect,we reveal dimensionality effects in an ensemble of interacting magnetic nanoparticles. Such effects are topical in current nanomagnetism research and highlight the opportunities of highresolution soft x-ray microscopy in magnetism research and beyond.
Hard x-ray multi-projection imaging for single-shot approaches
Villanueva-Perez, Pablo; Pedrini, Bill; Mokso, Rajmund; et al. (2018)
Optica
Quantitative interior x-ray nanotomography by a hybrid imaging technique
Guizar-Sicairos, Manuel; Boon, Jaap J.; Mader, Kevin; et al. (2015)
Optica
Hierarchical structures appear often in life and materials sciences, and their characterization profits greatly from imaging methods that allow seamless probing of various length scales without sacrificing image quality. X-ray tomography is particularly adept at probing 3D structures; however, zooming in on a region of interest results in a loss of quantitativeness of image contrast and suffers from artifacts unless a priori knowledge or assumptions about the sample are used. Here, we demonstrate a hybrid technique that exploits a micrometer-resolution overview to realize ab initio nanoscale interior tomography with quantitative contrast. In a study of avian eggshell, a model for bionanoporous materials, our approach reveals a complex arrangement of vesicles with sizes ranging from hundred nanometers to a few micrometers. We anticipate that such an approach can be widely adopted and benefited from at synchrotron and laboratory sources, for instance, where such zooming capabilities are already present or can be readily realized.

Publications 1 - 10 of 35

Journal: Optica

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