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It is commonly understood that, to cast light into a state with sub-Poissonian statistics, a strong optical nonlinearity is needed. The most common examples are resonance fluorescence of a two-level system, or a Kerr medium where the Kerr energy per photon U is much larger than the optical linewidth κ. In both cases, a single-photon nonlinearity is realized, whereby the presence of a single photon...
One of the cornerstones of quantum mechanics is that matter can possess both particle- and wave-like properties. Since the inception of quantum mechanics, such wavelike behaviour has been observed in ever more massive systems — ranging from electrons, neutrons, ultracold atoms, and even large molecules comprising many hundreds of atoms. An exciting route to further extend the exploration of quantum...
Stable and spectrally narrow laser sources referenced to ultrastable passive Fabry-Pérot cavities are invaluable for optical atomic clocks and they find important applications, e.g. in precision tests of relativity or novel radar applications. Ultimately the fractional frequency instability of the laser is limited by Brownian thermal noise of the cavity constituents.
The rising demand in ultrafast radiation sources has boosted the search for high power and high stability mode-locked fiber lasers, particularly at telecom wavelengths. In this work, we demonstrate the first ultrafast mode-locked fiber laser relying on InN as saturable absorber, centered at 1.5μm. The saturable absorber consists of a 1-μm-thick InN grown on a GaN-on-sapphire template deposited by...
We have realized a hybrid opto-electro-mechanical system [1], consisting of a radiofrequency (rf) resonato: capacitively coupled to a nanomechanical membrane, and read-out at the shot noise level by an optica interferometer. The oscillation of the mechanical resonator can alter the capacitance of the radiofrequency resonator leading to the modulation of transmitted signal. In our setup the rf resonator...
The development of all-optical, acousto-optical or electro-optical (EO) waveguides represents a stimulating challenge for the production of advanced functionalities in compact optical devices. In particular, high aspect ratio LiNbO3 ridge waveguides have attracted much interest over the past decade, due to their ability to enhance electro-optic effects while ensuring insertion losses lower than 3...
Yb:YAG thin-disk (TD) oscillators are able to deliver energetic femtosecond pulses without external amplification at hundreds of watts average power and MHz repetition rates [1, 2]. Such compact, high-power, low-noise sources are beneficial for scientific experiments and industrial micromachining. They also serve as a great starting point for spectral broadening, which allows transferring their power...
Fiber and bulk lasers form two distinct classes of solid-state laser, both of which have achieved tremendous success in various arenas, but they are not without their limitations. The long, thin geometry of a fiber allows excellent heat dissipation, which combined with a waveguiding structure provides stronger resilience to thermally-induced mode distortions than in bulk lasers, allowing diffraction-limited...
Terahertz (THz) and sub-THz frequency emitter-detector technology is receiving increasing attention because of key apphcations in several fields. In particular, ultrafast THz receivers are desired for compact, ultrafast spectroscopy and communication systems. While most of the available THz detectors (thermal, FET …) are currently limited in response time by slow thermal processes and/or by the read-out...
The emerging field of topological photonics aims to realize photonic structures which are resilient to fabrication imperfections by utilizing ideas developed in topology[1]. In photonics, the topological phases are defined on the reciprocal space and usually are associated with the formation of topologically protected (TP) defect states within photonic band-gaps. In this endeavor the manipulation...
Controlling the interaction of light and matter is the basis for diverse applications ranging from light technology to quantum information processing. Nowadays, many of these applications are based on nanophotonic structures. It turns out that the confinement of light in such nanostructures imposes an inherent link between its local polarization and its propagation direction, also referred to as spin-momentum...
Optical frequency combs provide an equidistant grid of optical frequency components, enabling a wide array of diverse and new technologies [1]. One such application is photonic microwave generation where optical frequency combs provide unprecedented low-noise performance via optical frequency division [2]. Although providing excellent performance, it comes at the expense of size and complexity. In...
Due to a strong light absorption by metals, it is believed that plasmonic nanostructures cannot be used for generating intensive radiation harmonics in the UV spectral range. We present results of investigation of the nonlinear optical interaction of laser radiation with a single gold nanostructure in the geometry of the Split-Hole Resonator (SHR) [1, 2] under the-state-of-the-art experimental realized...
Quantum cascade lasers (QCLs) are unipolar semiconductor devices emitting in the mid-and far-infrared spectral ranges. Due to their relatively narrow linewidths and short gain recovery times, these lasers have been deemed difficult, if not impossible, to passively mode lock (PML) [1, 2]. However, the successful mode locking of QCLs is of utmost importance as it could allow generation of ultrashort...
Already several years ago [3], it was suggested that a laser with optical injection can respond to external perturbations by emitting spikes if the perturbation overcomes a certain threshold, all the spikes being identical to each other, in complete analogy with the behaviour of the simple theta-model neuron [1]. The underlying explanation of this phenomenon lies in the isomorphism between a model...
We experimentally and theoretically examined the mode structure of half-disk lasers fabricated by cleaving whispering gallery mode (WGM)-disk lasers. The WGM lasers with a radii R of 50–150 μm emitting near 2.2 μm were fabricated using the GaSb-based quantum well structure [1]. The cleavage usually passes not through the centre of the disk with the deviation δ/R up to 20 % (Fig. 1a). Recently we have...
Monolithically integrated light sources on silicon are key for future semiconductor microchips that comprise Si CMOS and on-chip optical interconnects as prerequisite for more energy efficient computers and data centres. Recently, major advances were achieved regarding direct integration of III-V gain material on silicon without introducing threading dislocations, especially via heteroepitaxy of semiconductor...
In order to deliberately control the flow of optically encoded information, optical storage is an indispensable tool, but it must maintain all the advantages of optics, such as i.e. the coherence, the bandwidth and capacity. An elegant approach to this problem is to coherently transfer the information from optical to acoustic waves via an opto-mechanical nonlinearity, such as stimulated Brillouin...
Whispering-gallery resonators gain more and more interest in optical applications. Their combination of small dimensions, strong light confinement, and high quality factors make them ideally suited for optical frequency conversion. Here, their unique features not only allow operation with very small pump powers, they also allow covering the optical spectrum from the UV up to the mid-IR [1, 2, 3]....
All-dielectric and semiconductor nonlinear nanophotonics is an emerging field enabling efficient optical interactions between magnetic and electric resonances at sub-wavelength scales, thereby achieving high directionality and high figures of merit due to very low losses [1, 2]. It was shown that AlGaAs nanodisks with quadratic nonlinear susceptibility can provide second harmonic generation (SHG)...
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