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Singlet oxygen (1O2), an excited state of the oxygen molecule, is a crucial intermediate in many biological processes. In the clinical domain, it is generated in most applications of photodynamic therapy (PDT) via photoactivation of a photosensitizing drug. Direct detection of the 1O2 luminescence at 1270 nm wavelength is extremely challenging, due to the high reactivity of 1O2 that results in very...
Current frontier of cellular biology is the manipulation, analysis and sorting of single cells. Populations of cells in culture and in organisms, although considered nominally identical, often present some heterogeneity whose analysis may unravel the complexity of many biological phenomena [1]. Optical stretching is a powerful technique to study the mechanical properties of single suspended cells...
The monitoring of the heart beat and other parameters related to the cardiovascular system is required in the clinical context to perform the diagnosis of many dysfunctions and pathologies, such as arteriosclerosis or diabetes. By analyzing the shape of the heart pulse wave and how it changes during the propagation in the arterial tree, a comprehensive diagnosis of the arterial hardening and thickening...
Recently, polarimetric imaging of biological tissues has been shown to be a very promising technique for early detection of diseases such as lung, skin or colon cancer [1][2]. In order to apply polarization imaging to deep organs in situ, this technique must be associated to endoscopic ones. In this case, light reflected by the targeted area ("sample") is analyzed after its propagation along...
Grating stabilized diode lasers exist in many different configurations, typically using bulk and fiber Bragg gratings. In the last couple of years grating stabilized lasers based on a semiconductor gain chips coupled to integrated or planar lightwave circuits containing Bragg gratings have been demonstrated and developed. These devices not only exhibit excellent optical properties such as ultra-low...
Nanostructured materials consisting of metal nanoparticles (NPs) embedded in transparent dielectrics have attracted much attention as promising candidates for optical applications compatible with integrated devices. Their optical properties can be modified on an ultrafast time scale by a series of energy conversion and exchange processes following light pulse absorption at wavelengths close to their...
Arrays of semiconductor nanowires have been grown with exceptionally small optical mean free paths. These random arrays demonstrate significant fluctuations in transmission, allowing the investigation of mesoscopic light transport in a three dimensional medium.
Given the ever-growing demand of green energy, many efforts of the industrialized societies are spent in the development of new technologies for renewable energy. In particular, the nanophotonic community has been producing a great deal of alternative strategies to improve the performance of various photovoltaic technologies. Thin-film solar cells are the current state-of-the-art in solar energy technologies,...
Lasing from random media continues to generate significant interest[1]. A particular random system of interest is the periodic-on-average random system (PARS, in short), which comprises a random structure that has an underlying periodicity[2]. In this case, the passband and stopband characteristics of the underlying structure influence the modes of the random system. Despite the interesting transport...
Photothermal laser processing of ceramics and glass usually results in the appearance of microcracks and in the consequent severe devaluation of their mechanical properties. The former is due to extreme thermo-mechanical stress.
Modification of silver nanoparticles embedded in a glass substrate with femtosecond pulsed laser sources has recently been of great interest. These studies were fuelled by the observation of unique optical properties in terms of femtosecond pulsed laser-induced optical dichroism in these materials, leading to modification of the surface plasmon resonance (SPR) band of the embedded nanoparticles [1,...
The development of nanoscale sources of coherent light is a key element in the route towards nanoscale optical circuits. Because of their reduced size, nanoscale lasers sustain a very small number of optical modes and can contain only a few emitting dipoles as gain material. This has a strong impact on the laser characteristics. For instance, the laser can be subject to Cavity Quantum ElectroDynamics...
The nanostructured micro-optics technology [1], which has been used successfully to fabricate a wide range of micro-optical devices, gives unparalleled design freedom in the development of high frequency structures. Using successive stack-and-draw processes (Figure 1) features significantly below the wavelength of incident light can be achieved, allowing the development of micro-optical structures...
Hydrogen gas is used widely in scientific research and industry. Nanosized H2 sensors that can quickly and sensitively respond to hydrogen gas are vital for the safe use of all hydrogen-based applications[1,2]. Hydrogen sensors based on Pd nanostructures show promising results in speed, sensitivity, and ultralow power consumption[1-3]. A variety of hydrogen gas sensors based on palladium (Pd) nanowires...
Optofluidics refers to a class of devices and techniques that combine optics and fluidics. Biophotonics has been a major application of optofluidics partially because in biology we normally use light to make measurements of entities suspended in liquids. Therefore biophotonics naturally combines fluids and optics. The same is true in the field of solar fuels where chemicals in liquid form are exposed...
Direct integration of single photon emitters into easy-to-fabricate functional microstructures is a major step towards a future quantum optical technology. Because of its photostability and versatile spin properties the nitrogen vacancy center (NV center) in diamond is one of the most promising candidates as source of single photons [1]. One of its drawbacks lies in the properties of its host crystal...
Hybrid optical materials combining metallic plasmonic and dielectric photonic crystals in one hetero-structure possess several resonance mechanisms which critically influence light transport [1]. In particular, a hybrid consisting of a monolayer of dielectric spheres assembled on a metal film-coated substrate simultaneously supports dielectric and surface plasmon polaritons (SPPs), Fabry-Perot resonances...
We will demonstrate plasmonic and metamaterial based integrated nano-biosensors and ultrasensitive infrared absorption spectroscopy. These systems by enabling monitoring of molecular-protein interactions in real-time within aqueous solutions can be important for biomedical sciences and pharmacology.
Femtosecond laser structuring is applied to produce linear ion traps of AlN ceramics. Such ion trap can serve as an optical clock with exceptionally high long term stability [1]. The selection of techniques, applicable to the high precision micro structuring of AlN ceramics, is limited due to high hardness and fragility of the material. Laser structuring is very attractive for this application. However,...
It has been found that both in gases [1] and transparent materials plasma [2], produced by the leading part of tightly focused and intense femtosecond laser pulse, results in strong beam delocalization. It means that essential part of the ultra-short laser pulse energy (actually up to 99%) can be scattered outside the beam caustic. Correspondingly, this effect limits the intensity of light one can...
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