1,721,178 research outputs found
Photonics materials for the next millennium
No full textInformation technology will shape the world in the 21 Century. It has already begun to affect everything from our personal lives to global management. The transformation is a result of being been able to couple computers to high bandwidth optical telecommunication networks. The role of material research has been crucial in the development of three optical technologies of the emerging information revolution: semiconductor lasers, optical fibres and optical amplifiers. The discovery and optimization of new photonic materials is vital in the exploitation of new optical phenomena and the development of optical devices and systems. Recently structured photonic materials have created new opportunities for advanced optical technologies. Continued advances in photonic networks will depend on continued reduction in the cost of photonic components, increased functionality and increased levels of integration. Improved nonlinear optical materials, novel nonlinear fiber devices and a better understanding of light-matter interactions are still needed to cultivate the technology's success and widen its impact. As we move into the New Millennium, breakthrough capabilities will be achieved through engineered semiconductor, dielectric and nonlinear optical materials
Alignment-free dispersion measurement with interfering biphotons
No full textMeasuring the dispersion of photonic devices with small dispersion-length products is challenging due to the phase-sensitive and alignment-intensive nature of conventional methods. In this Letter, we demonstrate a quantum technique to extract the second- and third-order chromatic dispersion of a short single-mode fiber using a fiber-based quantum nonlinear interferometer. The interferometer consists of two cascaded fiber-based biphoton sources, with each source acting as a nonlinear beam splitter. A fiber under test is placed between these two sources and introduces a frequency-dependent phase that is imprinted on the biphoton spectrum (interferogram) at the output of the interferometer. This interferogram contains the dispersion properties of the test fiber. Our technique has three novel features: (1) the broadband nature of the biphoton sources used in our setup allows accurate dispersion measurements on test devices with small dispersion-length products; (2) our all-fiber common-path interferometer requires no beam alignment or phase stabilization; and (3) multiple phase-matching processes supported in our biphoton sources enable dispersion measurements at different wavelengths, which yields the third-order dispersion achieved for the first time, to the best of our knowledge, using a quantum optical technique
Breaking the limits in glass: From quantum interference to fs nanostructuring
No full textOptical glass fibres and waveguides dominate optical communications. The development of linear electrooptic modulators/switches and parametric frequency converters directly integrated into optical glass waveguide structures technologically is very attractive. However such components require a second-order optical nonlinearity - a χ(2) which is normally absent in glass owing to its inversion symmetry. Thus, when self-organized frequency doubling was first discovered wide-ranging studies ensued into the mechanism and properties of this unexpected phenomenon. The mystery of self-organized χ(2) gratings was finally solved on the basis of a new physical phenomenon - the coherent photogalvanic effect, consisting in quantum interference between light fields at two different frequencies, ω and 2ω, which excites a phase dependent current (coherent photocurrent). Coherent photocurrent creates quasi-phase matching χ(2) gratings. Moreover in the experiments on electric-field second harmonic generation in optical fibres the first evidence of phase dependent modulation of a total cross-section of ionization due to quantum interference (coherent photoconductivity) in solid state materials has been obtained [1]. Another interesting field demonstrating unusual light-matter interactions and properties of materials is modification of index of refraction and direct writing of photonic structures by ultrashort light pulses in glass. A critical advantage of using femtosecond pulses relative to longer pulses for optical writing and data storage is that such pulses can rapidly and precisely deposit energy in solids. This is the principle of femtosecond photosensitivity and 3D direct writing of photonic structures ranging from 3D waveguides to embedded Fresnel zone plates. This research has led to demonstration of new phenomena - anomalous anisotropic light scattering and form birefringence in glass [2]. The anisotropic phenomena have been interpreted in terms of self-induced index nano-gratings in glass and self-organized form birefringence, which is a new manifestation of self-organization under intense irradiation. The observed self-organized periodic structures are the smallest (20 nm width) and the strongest (-0.2 index change) ever created by light in transparent materials. Moreover these are the first gratings created by light-matter (electron plasma) interference [3]. In the talk I review properties and potential applications of glass and optical fibres modified by strong fields and related new phenomena
'Magna Carta for Eternity'
No full textMagna Carta encoded on a glass disk as five dimensional (5D) digital data using femtosecond laser writing presented to Salisbury Cathedra
Dataset for Non-Paraxial Polarization Spatio-Temporal Coupling in Ultrafast Laser Material Processing
No full textDataset supporting the article Patel, A., Tikhonchuk, V., Zhang, J., & Kazansky, P. (2017). Non-paraxial polarization spatio-temporal coupling in ultrafast laser material processing. Laser & Photonics Reviews. https://doi.org/10.1002/lpor.201600290
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Dataset for High-performance geometric phase elements in silica glass
No full textDataset to support the publication:
Drevinskas, R & Kazansky, P 2017, 'High-performance geometric phase elements in silica glass' APL Photonics. DOI: 10.1063/1.4984066
High-precision three-dimensional ultrafast laser direct nanostructuring of silica glass resulting in multi-layered space-variant dielectric metasurfaces embedded in volume is demonstrated. Continuous phase profiles of nearly any optical component are achieved solely by the means of geometric phase. Complex designs of half-wave retarders with 90% transmission at 532 nm and >95% transmission at >1 µm, including polarization gratings with efficiency nearing 90% and computer generated holograms with phase gradient of ~0.8pi rad/µm, were fabricated. Vortex half-wave retarder generating single beam optical vortex with tunable orbital angular momentum of up to ±100ℏ is shown. High damage threshold of silica elements enables simultaneous optical manipulation of large number of micro-objects using high-power laser beams. Thus, the continuous control of torque without altering the intensity distribution was implemented in optical trapping demonstration with a total of 5 W average power, which is otherwise impossible with alternate beam shaping devices. In principle, the direct-write technique can be extended to any transparent material that supports laser assisted nanostructuring, and can be effectively exploited for the integration of printed optics into multi-functional optoelectronic systems.</span
New science and art of femtosecond laser writing
No full textCommon beliefs that laser writing does not change when reversing beam scan or propagation direction are challenged. Recently discovered phenomena of quill and non-reciprocal femtosecond laser writing in glasses and crystals are reviewed
Extraordinary stability of femtosecond direct written structures
No full textWe report novel results on the stability of femtosecond direct written structures: a silica sample previously irradiated with ultrashort pulses was annealed at increasing temperatures till 1400° C where it crystallized. Our results show that the birefringent direct written structures are stable till a temperature close to the glass transition of silica. After annealing at a temperature as high as 1100° C the form birefringence of the structures is still present, proving that the nature of the laser induced anisotropy is related to a structural change
Self-assembled sub-wavelength structures and form birefringence created by femtosecond laser writing in glass: properties and applications
No full textProperties and applications of self-assembled sub-wavelength structures and related form birefringence produced by femtosecond laser writing in silica glass are reviewed
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