Papers by Ivan Divliansky
Applied Physics Letters, 2003
Journal of Optics
A new technology that includes a flexible holographic recording system using photo-thermo-refract... more A new technology that includes a flexible holographic recording system using photo-thermo-refractive (PTR) glass is demonstrated for creating so-called ‘holographic phase masks’ or HPMs. These diffractive optical elements are permanently recorded in the PTR glass, can be multiplexed as with normal holograms, do not require electric power to operate, and can perform near arbitrary beam phase transformations. The holographic setup includes a spatial light modulator that enables recording transmitting volume Bragg gratings (VBGs) with arbitrary phase patterns encoded into them. As a result, the desirable phase pattern is introduced in a beam that is diffracted by the VBG. These HPMs are tunable within the visible and near IR spectral regions and can be made achromatic, with spectral widths of up to 50 nm. Furthermore, they tolerate laser power densities on the order of several kW cm−2. Applications of HPMs include high-power, broadband laser beam shaping and modal analysis of complex beams profiles, both of which are demonstrated here.
To date, the realization of chip-scale optical interconnects has been inhibited by the lack of a ... more To date, the realization of chip-scale optical interconnects has been inhibited by the lack of a device technology that can provide optical functionality at a scale commensurate with integrated circuits. To overcome this limitation, I propose the realization of an "optical superhighway" ...
Laser Resonators, Microresonators, and Beam Control XXII
Optics & Laser Technology
Advanced materials (Deerfield Beach, Fla.), Jan 13, 2018
A novel photothermal process to spatially modulate the concentration of sub-wavelength, high-inde... more A novel photothermal process to spatially modulate the concentration of sub-wavelength, high-index nanocrystals in a multicomponent Ge-As-Pb-Se chalcogenide glass thin film resulting in an optically functional infrared grating is demonstrated. The process results in the formation of an optical nanocomposite possessing ultralow dispersion over unprecedented bandwidth. The spatially tailored index and dispersion modification enables creation of arbitrary refractive index gradients. Sub-bandgap laser exposure generates a Pb-rich amorphous phase transforming on heat treatment to high-index crystal phases. Spatially varying nanocrystal density is controlled by laser dose and is correlated to index change, yielding local index modification to ≈+0.1 in the mid-infrared.
Solid State Lasers XXVI: Technology and Devices
Components and Packaging for Laser Systems III, 2017
Cleo Qels 2010 Laser Science to Photonic Applications, 2010
We demonstrate a non-invasive diagnostic method of quantitative infrared (IR) imaging, applied he... more We demonstrate a non-invasive diagnostic method of quantitative infrared (IR) imaging, applied here to a series cascade of microring resonators fabricated in silicon-on-insulator. The IR images contain information on the otherwise inaccessible individual through-ports and the resonators themselves, providing coupling, loss and intensity-enhancement parameters for the individual rings.
Proceedings of Spie the International Society For Optical Engineering, Sep 1, 2010
This paper is a survey of recent achievements at the College of Optics and Photonics/CREOL at the... more This paper is a survey of recent achievements at the College of Optics and Photonics/CREOL at the University of Central Florida in the use of newly developed diffractive optical elements which are volume Bragg gratings recorded in a photo-thermo-refractive (PTR) glass. Three levels of semiconductor laser design are proposed to achieve high-power low-divergence output. The first level is coherent coupling of emitters by means of PTR Bragg gratings which provide excitation of only one common mode in a multichannel resonator. This type of phase locking automatically leads to a narrow spectral width of emission usually not exceeding a few tens of picometers. The second level is a change of the mechanism of transverse mode selection from spatial selection by apertures to angular selection by PTR Bragg gratings. This approach allows increasing of the aperture size without increasing the length and selecting of arbitrary mode but not necessarily a fundamental one. The third level is spectral beam combining by PTR Bragg gratings which redirect radiation from several high-power fiber lasers to co-propagate in the same direction with diffraction limited divergence. This approach allows simplification of the thermal management because only passive devices with low absorption (a PTR volume Bragg gratings) are placed in the path of high power laser beam.
Solid State Lasers XXV: Technology and Devices, 2016
Light: Science & Applications, 2016
Optically pumped lasers based on solution-processed thin-film gain media have recently emerged as... more Optically pumped lasers based on solution-processed thin-film gain media have recently emerged as low-cost, broadly tunable, and versatile active photonics components that can fit any substrate and are useful for, e.g., chemo-or biosensing or visible spectroscopy. Although single-mode operation has been demonstrated in various resonator architectures with a large variety of gain media-including dye-doped polymers, organic semiconductors, and, more recently, hybrid perovskites-the reported linewidths are typically on the order of a fraction of a nanometer or broader, i.e., the coherence lengths are no longer than a few millimeters, which does not enable high-resolution spectroscopy or coherent sensing. The linewidth is fundamentally constrained by the short photon cavity lifetime in the standard resonator geometries. We demonstrate here a novel structure for an organic thin-film solid-state laser that is based on a vertical external cavity, wherein a holographic volume Bragg grating ensures both spectral selection and output coupling in an otherwise very compact (,cm 3) design. Under short-pulse (0.4 ns) pumping, Fourier-transform-limited laser pulses are obtained, with a full width at half-maximum linewidth of 900 MHz (1.25 pm). Using 20-ns-long pump pulses, the linewidth can be further reduced to 200 MHz (0.26 pm), which is four times above the Fourier limit and corresponds to an unprecedented coherence length of 1 m. The concept is potentially transferrable to any type of thin-film laser and can be ultimately made tunable; it also represents a very compact alternative to bulky grating systems in dye lasers.
Applied optics, 2015
High-contrast filtering via multiple reflections between matched volume Bragg gratings (VBGs) is ... more High-contrast filtering via multiple reflections between matched volume Bragg gratings (VBGs) is demonstrated. The use of multiple reflections serves to increase the suppression ratio of the out-of-band spectral content such that contributions of grating sidelobes can be mitigated. The result is a device that retains spectral and angular selectivity and diffracts light into a single order with high efficiency but reshapes the spectral/angular response to achieve higher signal-to-noise ratios. We demonstrate that multipass spectral filters can be recorded with extremely high suppression ratios using reflecting Bragg gratings (RBGs) in three different configurations. These filters demonstrate roll-offs of over 150 dB/nm. Similarly, we demonstrate angular filtering by multipass transmitting gratings.
Frontiers in Optics 2015, 2015
Transversely chirped volume Bragg grating (TCVBG) provides tunability of resonant wavelength in d... more Transversely chirped volume Bragg grating (TCVBG) provides tunability of resonant wavelength in different designs of laser cavities. Resonant reflectivity suppression and quality deterioration of Gaussian beam reflected by TCVBG are calculated, together with spectral characteristics.
Components and Packaging for Laser Systems, 2015
Micromachining Technology for Micro-Optics and Nano-Optics V and Microfabrication Process Technology XII, 2007
The broad development of the micro-and nano-technologies in the past few years increased the need... more The broad development of the micro-and nano-technologies in the past few years increased the need of techniques capable of fabricating sub-micron structures with arbitrary surface profiles. Out of the several fabrication approaches (HEBS lithography, laser writing, etc.) the electron beam writing stands out as the one capable of the highest resolution, superior alignment accuracy and very small surface roughness. These characteristics make the technique greatly applicable in the fields of photonics and micro-opto-electro-mechanical-systems (MOEMS). Here we describe the specificity of fabricating 3D diffractive micro-and nano-optical elements using Leica EBPG 5000+ electron beam system. Parameters like speed of writing, dose accumulation, pattern writing specifics, etc. affect greatly the electronbeam resist properties and the desired 3D profile. We present data that can be used to better understand the different dependencies and therefore achieve better profile and surface roughness management. The results can be useful in future developments in the areas of integrated photonic circuits and MOEMS.
Optical Engineering, 2015
We present here a method to create spectrally addressable phase masks by encoding phase profiles ... more We present here a method to create spectrally addressable phase masks by encoding phase profiles into volume Bragg gratings, allowing these holographic elements to be used as phase masks at any wavelength capable of satisfying the Bragg condition of the hologram. Moreover, this approach enables the capability to encode and multiplex several phase masks into a single holographic element without cross-talk while maintaining a high diffraction efficiency. As examples, we demonstrate fiber mode conversion with near-theoretical conversion efficiency as well as simultaneous mode conversion and beam combining at wavelengths far from the original hologram recording wavelength. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.
Laser Beam Shaping XIV, 2013
ABSTRACT We demonstrate the recording of volume phase masks in the bulk of photo-thermo-refractiv... more ABSTRACT We demonstrate the recording of volume phase masks in the bulk of photo-thermo-refractive glass. Recording was produced by exposing the glass to UV radiation through binary amplitude masks. Depending on the profile of the amplitude mask either a binary volume phase mask or a grayscale phase mask may be produced. Volume phase masks have been used to generate Fresnel lenses, convert a Gaussian beam into higher order Hermite-Gauss and Laguerre-Gauss modes, to produce optical vortices, and to create aberration-correcting optical components.
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Papers by Ivan Divliansky