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We investigate the interaction between single quantum emitters and non-transversally polarized photons for which the electric field vector amplitude has a significant component in the direction of propagation. Even though this situation seems to be at odds with the description of light as a transverse wave, it regularly occurs when interfacing or manipulating emitters with non-paraxial, guided, or...
The absorption of a single photon by a single two-level system (TLS) in free space is a fundamental physical process. In this contribution, we present the experimental realization of a model system to simulate the dynamics of such an absorption experiment: Comparing the absorption process of a single photon by a single TLS and the incoupling dynamics of an optical resonator, one finds an analogy between...
Many highly reflective metals have been transformed into black or coloured metal by femtosecond pulsed laser [1]. After femtosecond laser processing, nano- and micro- structures formed on the metal surface can absorb around 85%–95% of incident light in the range from ultraviolet to infrared.
One of today's challenges to realize computing based on quantum mechanics is to reliably and scalably encode information in quantum systems. This is particularly crucial when dealing with promising approaches such as linear optics quantum computing (LOQC) in photonic circuits [1,2]. Although this method is in principle scalable, in practice it is limited by the probabilistic nature of spontaneous...
Unlike traditional methods of micromachining, focused ultrashort laser pulses of sufficiently high fluence makes it possible not only to avoid the majority of side effects, including temperature, but also to create a qualitatively new laser technology for the so-called "hard materials", i.e. glass-carbon.
Quantum theory says that a measurement on a quantum system modifies, in general, its state. An ideal, projective measurement brings the system into one of the observable's eigenstates. Such a "strong" measurement (SM) often consists of a series of "weak" ones (WM), each introducing smaller changes to the state until its complete projection. The speed at which the system is projected...
Making silver ion-doped glass by field-assisted ion exchange had so far two major applications: the production of optical waveguides, which utilises the change of refractive index [1], and the generation of silver nanoparticles due to annealing at higher temperatures [2]. Some groups replaced the annealing step by laser irradiation [3, 4], which resulted in low concentration of silver nanoparticles...
The realization of nonlinear optical effects at the single photon level would be a significant step forward for quantum information processing and communications. In particular, a strong dispersive and non-dissipative nonlinearity could enable the implementation of a two-photon phase gate. One possible strategy to reach such huge nonlinearities is to convert photons into strongly interacting particles,...
Laser technology has been extensively used for dental treatment since the 1990s [1]. In particular hard tissue ablation is performed by Er:YAG lasers due to their affinity with water and hydroxipatite, thus avoiding the formation of micro- and macro-cracks, and thermal damaged areas[2 - 5]. On the other hand Er:YAG lasers are affected by cumbersome instrumentation, and operation durations can be higher...
This paper will present our recent work on the application of pulsed laser processing for the synthesis and functionalization of new types of nanomaterias for organic electronic applications. Rapid and facile methodologies for the photochemical reduction [1], functionalization and doping of graphene oxide (GO) sheets, based on pulsed laser irradiation of GO in liquid or gas media, will be demonstrated...
Surface enhanced Raman spectroscopy (SERS) is a well-known surface-sensitive spectroscopic technique for enhancing Raman signal of molecules adsorbed on rough conducting surfaces. In present study a possible application of excimer laser irradiation in SERS substrate preparation is demonstrated. A polyimide foil on a rotating target holder was irradiated by 240 ArF excimer laser (λ=193 nm, FWHM=20...
Femtosecond laser direct writing techniques are very useful tools for rapid prototyping of integrated optics, since for example 3D- waveguide structures can be easy implemented without much effort in fused silica. Beside of this flexibility the waveguide diameter is preset by the numerical aperture of the objective used for processing the transparent substrate. Typical waveguide diameters processed...
Laser-Induced Forward Transfer (LIFT) is an additive and versatile direct-write technique for a single-step pattern- definition and material transfer [1]. In LIFT, a laser pulse is focused through a transparent substrate (the carrier) onto the rear side of a thin film of the material to be printed (the donor) that transfers a donor pixel to another substrate (the receiver) placed in close proximity...
In cavity optomechanics one can manipulate the dynamics of a nanomechanical resonator with light, and at the same time one can control light by tayloring its interaction with one (or more) mechanical resonances. A notable example of this kind of light beam control is provided by the optomechanical analogue of electromagnetically induced transparency (EIT), the so called optomechanically induced transparency...
We report the first on-chip quantum interference between photons generated in two discrete spontaneous four-wave mixing sources, and the manipulation of this biphotonic state using silicon-on-insulator integrated optics.
We report on a source of narrowband pairs of time-correlated photons generated via four-wave mixing in a laser-cooled atomic ensemble of 87Rb atoms. We employ a cascade decay level scheme in which two copropagating pump beams of 780nm and 776nm excite the atoms to the 5D3/2, F = 3 level and the photon pairs of wavelength 762nm and 795nm from the cascade decay are coupled into single mode fibers and...
To meet the ever-increasing demands of high resolution and versatility of microprocessing technology, diffractive optical elements (DOEs) are used to get the desired focal pattern [1]. The simplest phase DOE is a diffractive lens (DL). The focal length of a DL is given by f=fo λo/λ being fo the focal length for the central wavelength of the laser λo. Within the paraxial approximation, the focal irradiance...
Raman spectroscopy becomes more and more important for various application fields e.g. food safety, detection of hazardous compounds, or medical diagnostics. Especially portable Raman sensor systems e.g. hand-held devices have shown a rapid growth of interest in the last years. Here, diode lasers are attractive excitation light sources. However, weak Raman signals can be obscured by fluorescence of...
Optical coherence tomography (OCT) is a widely used optical imaging technology [1]. Current OCT systems contain a variety of fiber and free-space optical components, which add to the instrument size and cost. By utilizing a suitable mass-fabrication technology and a monolithic design, integrated optics can provide miniaturized OCT systems that offer dramatic cost and size reduction as well as more...
In the field of biological and chemical assays, much research activity has been directed towards the development of miniaturized instrumentations to fabricate highly integrated and automated ‘lab-on-a-chip’ systems based on microfluidics [1]. Such systems offer many advantages such as reduced reagent consumption, faster analysis and increased instrument portability. At present, most microfluidic technologies...
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