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A direct laser writing 3D nanolithography is a popular technique for fabrication of microstructures for a wide spectrum of scientific and industrial applications [1]. However, a systematic study of polarization control in light-assisted additive manufacturing of polymers is still limited. In glass patterning by nano-gratings, the polarisation control is essential for defining local form birefringence...
We report on the fabrication of highly ordered, multi-directional, complex surface structures that mimic the unique morphological features of certain species found in nature. In particular femtosecond laser pulses with various polarizations states, such as circular and vectorial, were utilized for structuring metal and dielectric surfaces. Experimental results showed that the direction of LIPSS in...
We report the new method for the measurement of the phase-relaxation time T2 of a medium with femtosecond time resolution. The method is based on the effect of quantum interference of entangled photons and does not require the actual use of a femtosecond light source. The method provides the practical and cost-efficient alternative to existing methods of ultrafast time-resolved spectroscopy [1].
In aperiodically poled quasi-phase-matching (QPM) crystals, parametric down-conversion (PDC) can generate very broadband pulsed squeezed light. This is because each part of the crystal will generate squeezed light at a different frequency [1]. But the emission will be thus inhomogeneously broadened, and one requires special measures to eliminate the chirp accompanying the pulses. This can be done...
The nonlinear light-matter interaction lies at the heart of controlling the electronic systems for the purpose of developing ultrafast optical switching and modulation devices [1], and attosecond laser technology [2]. In general, the interaction causes the formation of photon dressed state that is a quantum superposition state with energetically spaced sidebands and enables to generate the phase-locked...
Nonlinear Polarization Evolution (NPE) — a passive mode-locking technique — is successfully used in many all-fiber ultrafast oscillators. It is based on a temporal filtration of the pulse polarization state affected by a self-action due to the instantaneous Kerr nonlinearity. To work properly, most of NPE based architectures of fiber lasers contain pieces of standard optical fibers or bulk optical...
Intense, ultra-broadband terahertz (THz) pulses can drive major advances in ultrafast dynamics, nonlinear THz optics, and bio-material imaging [1,2]. Single and two-color filamentation of ultrashort laser pulses in gases have been extensively used for the generation of such pulses [3,4]. However, filament formation in gases is hindered by the need of high laser pulse energies, motivating the exploration...
Two-dimensional transition metal dichalcogenide (MX2) are receiving lot of attention in recent years due to their excellent electronic and optical properties which make them feasible for advanced photonics applications [1]. In particular Molybdenum-Disulfide (MoS2) has shown large exciton binding energy, strong spin-orbit interaction, and high carrier mobilities.
The need for microoptical elements in various emerging fields such as astrophotonics, nonlinear optics and biomedicine create a demand for a new generation optics that would be lightweight/compact, resilient to harsh environment and easily integrable in other devices. Ultrafast pulses based direct laser writing 3D nanolithography produced microlenses seem as one of the candidates for such applications...
For memory applications and optical control of qubits ultrafast manipulation and high coupling efficiencies are desirable. Ultrafast coherent control can be achieved by the off-resonant Raman scheme [1]. There exist several colour centres with an optically accessible lambda-type energy structure which offer a level splitting large enough for broadband laser pulses.
Lithium niobate whispering-gallery resonators (WGRs) show high intensity enhancement due to small mode volumes and high Q-factors. With bulk WGRs, shaped by diamond-blade-cutting tools followed by surface polishing, Q-factors in the range of 1011 have been demonstrated, which make them of significant interest for e.g. nonlinear-optical frequency conversion [1]. However, WGRs are still rare in commercial...
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...
The Optical Frequency Comb (OFC) represents a cornerstone of precision metrology, because it provides a clockwork to down-convert hundreds of THz of optical frequency standards to the countable and traceable radio frequency (RF) domain. In particular, for a future redefinition of the Coordinated Universal Time by an optical atomic transition [1], it will be an essential ingredient. Nowadays, narrowband...
The continued remarkable advances in optical clocks and oscillators has led to a parallel strong development of optical clock networks [1]. Such networks have the potential to support a wide range of applications from basic time/frequency dissemination, to clock-based geodesy, to tests of general relativity [1]. To support optical clocks/oscillators at their highest accuracy and precision, these networks...
Diamond is an exceptional material due to its hardness, high thermal conductivity and transparency from the UV to far IR. Recently it has caught the attention of the scientific community because it is the host of different color centers that can be used for magnetic sensing applications and quantum computing [1]. One of the most promising of these defects is the nitrogen-vacancy (NV) center. The electrons...
Exposure of silica glass to focused femtosecond laser radiation produces a variety of structural modifications [1] that are accompanied by a localized change in volume [2, 3]. This volume change can be used to apply displacements in a controlled manner, allowing the generation of intense, localized stress fields [4] whose magnitude, orientation, and shape are easily manipulated through tuning of the...
Fibers are considered as extraordinary tabletop laboratories to investigate optical turbulence and optical rogue waves (ORW). However ultrafast measurement of random optical power fluctuations is a challenging experimental task and the typical sub-picosecond timescale prevented-up to now-time-resolved observations of the awaited dynamics. We report the first single-shot recordings of ORW emerging...
Monolayers of transition metal dichalcogenides (TMDs) are promising new materials for future 2D nanoelectronic systems.1 With their tunable direct gap in the visible range of the optical spectrum and high surface-to-volume ratio, these 2D semiconducting systems are ideal for field-effect transistors, photovoltaics, light-emitting diodes (LEDs), single-atom storage, molecule sensing, quantum-state...
Although shaping of fields around nanostructures is widely studied in plasmonics, the influence of the field inside the nanostructures is often overlooked. The linear field distribution inside the structure taken to the third power causes third-harmonic generation, a nonlinear optical response of matter. We demonstrate how this simple fact can be used to shape complex fields around a single particle...
Ultrafast transmission electron microscopy is a promising laser-pump electron-probe technique, which allows for studying ultrafast dynamics with both high spatial and temporal resolution [1]. Besides, the high spatial and temporal coherence of the pulsed electron beam enables a coherent manipulation of the free-electron quantum state [2] by inelastic scattering in optical near-fields [3-5]. Upon traversal...
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