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Bessel beams exploit conical energy flow to yield near-uniform intensity along a line focus which has been shown to be extremely attractive for laser processing in dielectrics. At high power, however, the nonlinear Kerr effect is known to induce significant oscillations of the on-axis intensity which is deleterious for machining applications. Here, we show through theory and numerical modelling how...
Recent advances in cavity quantum optomechanics have enabled breakthroughs such as ground state cooling of mechanical motion, observation of quantum backaction, standard quantum limit of position measurement and entanglement between optical and mechanical degrees of freedom [1]. Simultaneously, the upgraded version of current gravitational-wave interferometers is expected to suffer from optomechanical...
Fibre lasers display complex dynamical regimes which involve nonlinear interactions of millions of cavity modes. Recently, the transition to “optical turbulence” [1] (in analogy with the laminar-turbulence transition in hydrodynamic) was experimentally studied and was shown to be a phase transition which is accompanied by the occurrence of temporal correlations in the laser intensity with specific...
Special laser applications ranging from laser material processing, especially micromachining, to medical applications, metrology and spectroscopy demand transform limited ps pulses, often synchronized with a fs source [1]. Here, we present spectral compression of fs pulses inside a regenerative Yb:YAG laser amplifier [2] generated by a mode-locked Yb:KGW oscillator (see Fig. 1a). For spectral shaping...
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...
Semiconductor microcavities can be engineered to produce strong coupling between photons and quantum well excitons leading to the formation of new eigenstates called polaritons. Due to their peculiar dispersion, enabling non-equilibrium Bose-Einstein condensation [1], and their straightforward experimental accessibility, microcavity polaritons have gained considerable interest in recent years. Polariton...
Mid-infrared coherent sources at 3–4 μm have a wide variety of applications that include, but are not limited to gas sensing, material processing and production control. The MgO-doped periodically poled lithium niobate (MgO:PPLN) crystal is a well-known nonlinear element for quasi-phase-matched optical parametric oscillators (OPOs) typically pumped by 1-μm laser radiation [1]. However, strong multi-phonon...
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...
Pulse burst generation has important applications in material processing [1], seeding of free electron lasers [2] and coherent pulse stacking [3]. In particular, coherent pulse stacking technique allows further scaling of fiber and solid-state amplifiers by splitting the seed pulse into multiple replicas and stacking them into a single dominant pulse after the amplification. For this task, a pulse...
Satellite-based laser-based remote sensing (lidar) of the atmosphere can be used for meteorology, atmospheric chemistry and climate change but requires high energy (100mJ-class) lasers with precision wavelength control. A high energy Alexandrite laser source is an interesting alternative to Nd:YAG in future Earth Observation missions with its added scientific benefit of broad wavelength tunability...
Modulation instability (MI) refers to a process where a weak periodic perturbation of an intense continuous wave (CW) grows exponentially as a result of the interplay between dispersion and nonlinearity. In its most basic manifestation, it can be observed in homogeneous optical fibers in the anomalous dispersion regime. Another kind of MI, named parametric instability (PI), is induced by the periodic...
Femtosecond (fs) laser pulse sources have become increasingly popular in the last decade as a result of their practical features, such as insensitivity to environmental variations, versatile designs, high power outputs. However, much of the progress is with non-integrated specialty fibers, which involve some compromise on these practical features. Monolithic fiber chirped pulse amplification (CPA)...
High brightness semiconductor laser sources with modulation capacity are emerging candidates for an increasing number of applications. We have recently presented an integrated three section Master Oscillator Power Amplifier (MOPA) [1] to be used in space-borne Random Modulated Continuous Wave (RM-CW) Integrated Path Differential Absorption (IPDA) lidar systems for atmospheric CO2 detection [2]. The...
Mid-infrared (MIR) frequency comb sources enable high-speed and accurate detection of various species, since many molecules possess their fingerprints in this wavelength range. Usually, broadband radiation in this spectral region is obtained from optical parametric oscillators (OPOs), which provide high output power and broad tuning capabilities [1]. However, OpO sources require locking of the cavity...
Femtosecond 1 μm lasers are widely used in numerous scientific and industrial applications [1, 2]. Such oscillators are intensively developed and ultrafast sub-100 fs operation has been already demonstrated in several ytterbium-doped active media. One of the most interesting among them and relatively shortly investigated is Yb:CaF2. This is a simple cubic crystal, with very broadband emission spectrum...
Harmonic mode-locking of a solid-state bulk laser combines the benefits of long resonators with large pulse energy and high repetition rates. With this technique it is possible to operate a system at different repetition rates without changing the optical setup. The signal to noise ratio of a fundamentally mode-locked oscillator is typically much better than in harmonic operation [1]. In this contribution...
Recent advances on Ytterbium ultrafast lasers have led to compact and versatile systems with high average output power, potentially high pulse energy and easily tunable repetition rate. Such lasers are well suited for time-resolved pump-probe experiments, a field which involves a wide range of techniques spanning from X-rays diffraction imaging and spectroscopy to asynchronous optical sampling (ASOPS)...
High repetition rate femtosecond VIS radiation is normally generated in optical parametric oscillators (OPOs) either by generating VIS light via intra-cavity SHG or SFG [1, 2] or in VIS OPOs employing Ti:sa as a pump laser [3, 4]. Recently we demonstrated an efficient intra-cavity SFG in a non-collinear OPO (NOPO) pumped by thin disk oscillator [5]. Here, we present a NOPO system, pumped by the high...
An optical vortex, e.g., Laguerre-Gaussian mode, has been widely applied to a variety of research activities, such as super resolution microscopes, spatial division multiplexing telecommunications, and microfabrications, because it carries an annular spatial form and orbital angular momentum characterized by h per photon (where / is an integer defined as the topological charge) associated with its...
Midinfrared frequency combs are a promising tool for new applications in chemical imaging and sensing, as they can directly access molecular vibrations in the molecular fingerprint wavelength region [1]. Practical laser sources are moving steadily from few micrometer wavelengths further into the fingerprint region to the 10 μm region. For practical applications of midinfrared light, difference frequency...
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