We explore the efficacy of a hyphenated photonic crystal fibre microflow reactor-high-resolution mass spectrometer system as a method for screening the activity of potential new photoactivatable drugs. The use of light to activate drugs is an area of current development as it offers the possibility of reduced side effects due to improved spatial and temporal targeting and novel mechanisms of anticancer activity. The di-nuclear ruthenium complex [{(eta(6)-indan) RuCl}(2)(mu-2,3-dpp)](PF6)(2), previously studied by Magennis et al. (Inorg. Chem., 2007, 46, 5059) is used as a model drug to compare the system to standard irradiation techniques. The photodecomposition pathways using blue light radiation are the same for PCF and conventional cuvette methods. Reactions in the presence of small biomolecules 50-guanosine monophosphate (5'-GMP), 5'-adenosine monophosphate (5'-AMP), L-cysteine (L-Cys) and glutathione (gamma-L-glutamyl-L-cysteinyl-glycine, GSH) were studied. The complex was found to bind to nucleobases in the dark and this binding increased upon irradiation with 488 nm light, forming the adducts [(eta(6)-indan) Ru2(mu-2,3-dpp) + 5'-GMP](2+) and [(eta(6)-indan) Ru + (5'-AMP)]+. These findings are consistent with studies using conventional methods. The dinuclear complex also binds strongly to GSH after irradiation, a possible explanation for its lack of potency in cell line testing. The use of the PCF-MS system dramatically reduced the sample volume required and reduced the irradiation time by four orders of magnitude from 14 hours to 12 seconds. However, the reduced sample volume also results in a reduced MS signal intensity. The dead time of the combined system is 15 min, limited by the intrinsic dead volume of the HR-MS.
All-optical control of unipolar pulse generation in a resonant medium with nonlinear field coupling
A. V. Pakhomov,
R. M. Arkhipov,
I. V. Babushkin,
M. V. Arkhipov,
Yu. A. Tolmachev,
N. N. Rosanov
We study the optical response of a resonant medium possessing nonlinear coupling to an external field driven by a few-cycle pump pulse sequence. We demonstrate the possibility of directly producing unipolar half-cycle pulses from the medium possessing an arbitrary nonlinearity, by choosing the proper pulse-to-pulse distance of the pump pulses in the sequence. We examine various ways of shaping the medium response using different geometrical configurations of nonlinear oscillators and different wavefront shapes for the excitation pulse sequence. Our approach defines a general framework to produce unipolar pulses of controllable form.
Effect of stray fields on Rydberg states in hollow-core PCF probed by
higher-order modes
G. Epple,
N. Y. Joly,
T. G. Euser,
P. St. J. Russell,
R. Loew
The spectroscopy of atomic gases confined in hollow-core photonic crystal fiber (HC-PCF) provides optimal atom-light coupling beyond the diffraction limit, which is desirable for various applications such as sensing, referencing, and nonlinear optics. Recently, coherent spectroscopy was carried out on highly excited Rydberg states at room temperature in a gas-filled HC-PCF. The large polarizability of the Rydberg states made it possible to detect weak electric fields inside the fiber. In this Letter, we show that by combining highly excited Rydberg states with higher-order optical modes, we can gain insight into the distribution and underlying effects of these electric fields. Comparisons between experimental findings and simulations indicate that the fields are caused by the dipole moments of atoms adsorbed on the hollow-core wall. Knowing the origin of the electric fields is an important step towards suppressing them in future HC-PCF experiments. Furthermore, a better understanding of the influence of adatoms will be advantageous for optimizing electric-fieldsensitive experiments carried out in the vicinity of nearby surfaces. (C) 2017 Optical Society of America
On diagnostics of media using extremely short terahertz radiation pulses
N. N. Rosanov,
M. V. Arkhipov,
R. M. Arkhipov,
A. V. Pakhomov,
I. V. Babushkin
OPTICS AND SPECTROSCOPY
123
(1)
100-104
(2017)
| Journal
The possibility of diagnosing the linear and nonlinear electrodynamic susceptibilities of media by examining the time profiles of extremely short terahertz radiation pulses (using pulsed terahertz spectroscopy methods) that are incident on a thin layer of a medium under study, are reflected from the layer, and are transmitted through it is shown theoretically. In the general case, the linear and nonlinear susceptibilities of different orders can be found by solving linear integral equations. Diagnostics is considerably simplified in the case of an isolated resonance of a medium with homogeneous spectral broadening, which is modeled by the response of an anharmonic oscillator.
PHz-Wide Spectral Interference Through Coherent Plasma-Induced Fission of Higher-Order Solitons
F. Koettig,
F. Tani,
J. C. Travers,
P. St. J. Russell
We identify a novel regime of soliton-plasma interactions in which high-intensity ultrashort pulses of intermediate soliton order undergo coherent plasma-induced fission. Experimental results obtained in gas-filled hollow-core photonic crystal fiber are supported by rigorous numerical simulations. In the anomalous dispersion regime, the cumulative blueshift of higher-order input solitons with ionizing intensities results in pulse splitting before the ultimate self-compression point, leading to the generation of robust pulse pairs with PHz bandwidths. The novel dynamics closes the gap between plasma-induced adiabatic soliton compression and modulational instability.
Higher-order mode suppression in twisted single-ring hollow-core photonic crystal fibers
N. N. Edavalath,
M. C. Guenendi,
R. Beravat,
G. K. L. Wong,
M. H. Frosz,
J. -M. Menard,
P. St. J. Russell
A hollow-core single-ring photonic crystal fiber (SR-PCF) consists of a ring of capillaries arranged around a central hollow core. Spinning the preform during drawing introduces a continuous helical twist, offering a novel means of controlling the modal properties of hollow-core SR-PCF. For example, twisting geometrically increases the effective axial propagation constant of the LP01-like modes of the capillaries, providing a means of optimizing the suppression of HOMs, which occurs when the LP11-like core mode phase-matches to the LP01-like modes of the surrounding capillaries. (In a straight fiber, optimum suppression occurs for a capillary-to-core diameter ratio d/D = 0.682.) Twisting also introduces circular birefringence (to be studied in a future Letter) and has a remarkable effect on the transverse intensity profiles of the higher-order core modes, forcing the two-lobed LP11-like mode in the untwisted fiber to become three-fold symmetric in the twisted case. These phenomena are explored by means of extensive numerical modeling, an analytical model, and a series of experiments. Prism-assisted side-coupling is used to measure the losses, refractive indices, and near-field patterns of individual fiber modes in both the straight and twisted cases. (C) 2017 Optical Society of America
Continuously wavelength-tunable high harmonic generation via soliton dynamics
Francesco Tani,
Michael H. Frosz,
John C. Travers,
Philip St. J. Russell
We report the generation of high harmonics in a gas jet pumped by pulses self-compressed in a He-filled hollow-core photonic crystal fiber through the soliton effect. The gas jet is placed directly at the fiber output. As the energy increases, the ionization-induced soliton blueshift is transferred to the high harmonics, leading to emission bands that are continuously tunable from 17 to 45 eV. (C) 2017 Optical Society of America
Characterization and shaping of the time-frequency Schmidt mode spectrum
of bright twin beams generated in gas-filled hollow-core photonic
crystal fibers
M. A. Finger,
N. Y. Joly,
P. St. J. Russell,
M. V. Chekhova
We vary the time-frequency mode structure of ultrafast pulse-pumped modulational instability (MI) twin beams in an argon-filled hollow-core kagome-style photonic crystal fiber by adjusting the pressure, pump pulse chirp, fiber length, and parametric gain. Compared to solid-core systems, the pressure-dependent dispersion landscape brings increased flexibility to the tailoring of frequency correlations, and we demonstrate that the pump pulse chirp can be used to tune the joint spectrum of femtosecond-pumped.(3) sources. We also characterize the resulting mode content, not only by measuring the multimode second-order correlation function g((2)), but also by directly reconstructing the shapes and weights of time-frequency Schmidt (TFS) modes. We show that the number of modes directly influences the shot-to-shot pulse-energy and spectral-shape fluctuations in MI. Using this approach we control and monitor the number of TFS modes within the range from 1.3 to 4 using only a single fiber.
Generation of broadband mid-IR and UV light in gas-filled single-ring hollow-core PCF
Marco Cassataro,
David Novoa,
Mehmet C. Guenendi,
Nitin N. Edavalath,
Michael H. Frosz,
John C. Travers,
Philip St. J. Russell
We report generation of an ultrafast supercontinuum extending into the mid-infrared in gas-filled single-ring hollow-core photonic crystal fiber (SR-PCF) pumped by 1.7 mu m light from an optical parametric amplifier. The simple fiber structure offers shallow dispersion and flat transmission in the near and mid-infrared, enabling the generation of broadband spectra extending from 270 nm to 3.1 mu m, with a total energy of a few mu J. In addition, we demonstrate the emission of ultraviolet dispersive waves whose frequency can be tuned simply by adjusting the pump wavelength. SR-PCF thus constitutes an effective means of compressing and delivering tunable ultrafast pulses in the near and mid-infrared spectral regions. (C) 2017 Optical Society of America
Polarization-Selective Out-Coupling of Whispering-Gallery Modes
Florian Sedlmeir,
Matthew R. Foreman,
Ulrich Vogl,
Richard Zeltner,
Gerhard Schunk,
Dmitry V. Strekalov,
Christoph Marquardt,
Gerd Leuchs,
Harald G. L. Schwefel
Whispering-gallery mode (WGM) resonators are an important platform for linear, nonlinear, and quantum optical experiments. In such experiments, independent control of in-coupling and out-coupling rates to different modes can lead to higher conversion efficiencies and greater flexibility in the generation of nonclassical states based on parametric down-conversion. In this work, we introduce a scheme that enables selective out-coupling of WGMs belonging to a specific polarization family, while the orthogonally polarized modes remain largely unperturbed. Our technique utilizes material birefringence in both the resonator and the coupler such that a negative (positive) birefringence allows for polarization-selective coupling to TE (TM) WGMs. We formulate a refined coupling condition suitable for describing the case where the refractive indices of the resonator and the coupler are almost the same, from which we derive a criterion for polarization-selective coupling. Finally, we experimentally demonstrate our proposed method using a lithium niobate disk resonator coupled to a lithium niobate prism, where we show a 22-dB suppression of coupling to TM modes relative to TE modes.
Coherent control of flexural vibrations in dual-nanoweb fibers using phase-modulated two-frequency light
J. R. Koehler,
R. E. Noskov,
A. A. Sukhorukov,
D. Novoa,
P. St. J. Russell
Coherent control of the resonant response in spatially extended optomechanical structures is complicated by the fact that the optical drive is affected by the backaction from the generated phonons. Here we report an approach to coherent control based on stimulated Raman-like scattering, in which the optical pressure can remain unaffected by the induced vibrations even in the regime of strong optomechanical interactions. We demonstrate experimentally coherent control of flexural vibrations simultaneously along the whole length of a dual-nanoweb fiber, by imprinting steps in the relative phase between the components of a two-frequency pump signal, the beat frequency being chosen to match a flexural resonance. Furthermore, sequential switching of the relative phase at time intervals shorter than the lifetime of the vibrations reduces their amplitude to a constant value that is fully adjustable by tuning the phase modulation depth and switching rate. The results may trigger new developments in silicon photonics, since such coherent control uniquely decouples the amplitude of optomechanical oscillations from power-dependent thermal effects and nonlinear optical loss.
Population density gratings induced by few-cycle optical pulses in a resonant medium
R. M. Arkhipov,
A. V. Pakhomov,
M. V. Arkhipov,
I. Babushkin,
A. Demircan,
U. Morgner,
N. N. Rosanov
Creation, erasing and ultrafast control of population density gratings using few-cycle optical pulses coherently interacting with resonant medium is discussed. In contrast to the commonly used schemes, here the pulses do not need to overlap in the medium, interaction between the pulses is mediated by excitation of polarization waves. We investigate the details of the dynamics arising in such ultrashort pulse scheme and develop an analytical theory demonstrating the importance of the phase memory effects in the dynamics.
Numerical and experimental analysis of polarization dependent gain
vector in Brillouin amplification system
Shan Cao,
Shangran Xie,
Fei Liu,
Xiaoping Zheng,
Min Zhang
The polarization dependent gain (PDG) of Brillouin amplification systems is numerically investigated in detail by solving a new model describing the evolution of PDG vector along the fiber with random birefringence. In this model both the modulus and orientation of the PDG vector are considered. By including the temporal distribution of fiber birefringence, the statistical properties of the PDG vector, including its mean value and standard deviation, are presented as function of fiber beat length, input pump power and fiber length, which can be directly applied in practice to estimate the performance of Brillouin amplification systems in term of its polarization dependence. Experimental results on a Brillouin amplification system are also reported to support the validity of our model. The analysis presented here helps to gain insight for the properties of PDG vector in any SBS systems.
Stabilization of class-B broad-area laser emission by external optical
injection
A. V. Pakhomov,
R. M. Arkhipov,
N. E. Molevich
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
34
(4)
756-763
(2017)
| Journal
We theoretically examine the effect of external optical injection on the spatiotemporal dynamics of class-B broad-area lasers. We demonstrate that optical injection can efficiently stabilize the intrinsic transverse instabilities in such lasers associated with both the boundaries of the pumping area and with the bulk nonlinearities of the active medium. Stabilizing action of optical injection is shown to be closely related to the suppression of inherent relaxation oscillations behavior. (C) 2017 Optical Society of America
Helically twisted photonic crystal fibres
P. St. J. Russell,
Ramin Beravat,
G. K. L. Wong
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL
AND ENGINEERING SCIENCES
375
(2087)
20150440
(2017)
| Journal
Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left-and rightspinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic 'space', cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of 'numerical experiments' based on finite-element solutions of Maxwell's equations in a helicoidal frame.
This article is part of the themed issue 'Optical orbital angular momentum'.
Broadband, Lensless, and Optomechanically Stabilized Coupling into Microfluidic Hollow-Core Photonic Crystal Fiber Using Glass Nanospike
Richard Zeltner,
Shangran Xie,
Riccardo Pennetta,
Philip St J. Russell
We report a novel technique for launching broadband laser light into liquid-filled hollow-core photonic crystal fiber (HC-PCF). It uniquely offers self alignment and self-stabilization via optomechanical trapping of a,fused silica nanospike, fabricated by thermally tapering and chemically etching a single mode fiber into a tip diameter of 350 nm. We show that a trapping laser, deliirering similar to 300 mW at 1064 nm, can be used to optically align and stably maintain the iianospike at the core center. Once this is done, a weak broadband supercontinuum signal (similar to 575-1064 nm) can be efficiently and close to achromatically launched in the HC-PCF. The system is robust against liquid-flow in either direction inside the HC-PCF, and the Fresnel back-reflections are reduced to negligible levels compared to free-space launching or butt-coupling. The results are of potential relevance for any application where the efficient delivery of broadband light into liquid-core waveguides is desired.
Generation of spectral clusters in a mixture of noble and Raman-active
gases (vol 41, pg 5543, 2016)
Pooria Hosseini,
Amir Abdolvand,
Philip St. J. Russell
Christos Markos,
John C. Travers,
Amir Abdolvand,
Benjamin J. Eggleton,
Ole Bang
REVIEWS OF MODERN PHYSICS
89
(4)
045003
(2017)
| Journal
This article offers an extensive survey of results obtained using hybrid photonic-crystal fibers (PCFs) which constitute one of the most active research fields in contemporary fiber optics. The ability to integrate novel and functional materials in solid-and hollow-core PCFs through various postprocessing methods has enabled new directions toward understanding fundamental linear and nonlinear phenomena as well as novel application aspects, within the fields of optoelectronics, material and laser science, remote sensing, and spectroscopy. Here the recent progress in the field of hybrid PCFs is reviewed from scientific and technological perspectives, focusing on how different fluids, solids, and gases can significantly extend the functionality of PCFs. The first part of this review discusses the efforts to develop tunable linear and nonlinear fiber-optic devices using PCFs infiltrated with various liquids, glasses, semiconductors, and metals. The second part concentrates on recent and state-of-the-art advances in the field of gas-filled hollow-core PCFs. Extreme ultrafast gas-based nonlinear optics toward light generation in the extreme wavelength regions of vacuum ultraviolet, pulse propagation, and compression dynamics in both atomic and molecular gases, and novel soliton-plasma interactions are reviewed. A discussion of future prospects and directions is also included.
Generation of microjoule pulses in the deep ultraviolet at megahertz repetition rates
Felix Koettig,
Francesco Tani,
Christian Martens-Biersach,
John C. Travers,
Philip St J. Russell
Although ultraviolet (UV) light is important in many areas of science and technology, there are very few if any lasers capable of delivering wavelength-tunable ultrashort UV pulses at high repetition rates. Here we report the generation of deep UV laser pulses at megahertz repetition rates and microjoule energies by means of dispersive wave (DW) emission from self-compressed solitons in gas-filled single-ring hollow-core photonic crystal fiber (SR-PCF). Pulses from an ytterbium fiber laser (similar to 300 fs) are first compressed to <25 fs in a SR-PCF-based nonlinear compression stage and subsequently used to pump a second SR-PCF stage for broadband DW generation in the deep UV. The UV wavelength is tunable by selecting the gas species and the pressure. Through rigorous optimization of the system, in particular employing a large-core fiber filled with light noble gases, we achieve 1 mu J pulse energies in the deep UV, which is more than 10 times higher, at average powers more than four orders of magnitude greater (reaching 1 W) than previously demonstrated, with only 20 mu J pulses from the pump laser. (C) 2017 Optical Society of America
Radiation of a resonant medium excited by few-cycle optical pulses at
superluminal velocity
R. M. Arkhipov,
A. V. Pakhomov,
M. V. Arkhipov,
I. Babushkin,
Yu A. Tolmachev,
N. N. Rosanov
Recent progress in generation of optical pulses of durations comparable to one optical cycle has presented great opportunities for studies of the fundamental processes in matter as well as time-resolved spectroscopy of ultrafast processes in nonlinear media. It opened up a new area of research in modern ultrafast nonlinear optics and led to appearance of the attosecond science. In parallel, a new research area related to emission from resonant media excited by superluminally propagating ultrashort bursts of electromagnetic radiation has been actively developed over the last few years. In this paper, we review our recent results on theoretical analysis of the Cherenkov-type radiation of a resonant medium excited by few-cycle optical pulses propagating at superluminal velocity. This situation can be realized when an electromagnetic pulse with a plane wavefront incidents on a straight string of resonant atoms or a spot of light rotates at very large angular frequency and excites a distant circular string of resonant dipoles. Theoretical analysis revealed some unusual and remarkable features of the Cherenkov radiation generated in this case. This radiation arises in a transient regime which leads to the occurrence of new frequencies in the radiation spectrum. Analysis of the characteristics of this radiation can be used for the study of the resonant structure properties. In addition, a nonlinear resonant medium excited at superluminal velocity can emit unipolar optical pulses, which can be important in ultrafast control of wave-packet dynamics of matter. Specifics of the few-cycle pulse-driven optical response of a resonant medium composed of linear and nonlinear oscillators is discussed.
Universality of Coherent Raman Gain Suppression in Gas-Filled Broadband-Guiding Photonic Crystal Fibers
Pooria Hosseini,
M. K. Mridha,
D. Novoa,
A. Abdolvand,
P. St. J. Russell
As shown in the early 1960s, the gain in stimulated Raman scattering (SRS) is drastically suppressed when the rate of creation of phonons (via a pump-to-Stokes conversion) is exactly balanced by the rate of phonon annihilation (via a pump-to-anti-Stokes conversion). This occurs when the phonon coherence waves-synchronized vibrations of a large population of molecules-have identical propagation constants for both processes; i. e., they are phase-velocity matched. As recently demonstrated, hydrogen-filled photonic crystal fiber pumped in the vicinity of its zero-dispersion wavelength provides an ideal system for observing this effect. Here we report that Raman gain suppression is actually a universal feature of SRS in gas-filled hollow-core fibers and that it can strongly impair SRS even when the phase mismatch is high, particularly at high pump powers when it is normally assumed that nonlinear processes become more (not less) efficient. This counterintuitive result means that intermodal stimulated Raman scattering (for example, between LP01 and LP11 core modes) begins to dominate at high power levels. The results reported have important implications for fiber-based Raman shifters, amplifiers, or frequency combs, especially for operation in the ultraviolet, where the Raman gain is much higher.
We introduce a novel design of anti-resonant fibers with negative-curvature square cores to be employed in 1.55 and 2.94 mu m transmission bands. The fibers have low losses and single-mode operation via optimizing the negative curvature of the guiding walls. The first proposed fiber shows a broadband transmission window spanning 0.9-1.7 mu m, with losses of 0.025 and 0.056 dB/m at 1.064 and 1.55 mu m, respectively. The second proposed fiber has approximately a 0.023 dB/m guiding loss at 2.94 mu m with a small cross-sectional area, useful for laser micromachining applications. (C) 2017 Optical Society of America
Enhanced Control of Transient Raman Scattering Using Buffered Hydrogen in Hollow-Core Photonic Crystal Fibers
P. Hosseini,
D. Novoa,
A. Abdolvand,
P. St. J. Russell
Many reports on stimulated Raman scattering in mixtures of Raman-active and noble gases indicate that the addition of a dispersive buffer gas increases the phase mismatch to higher-order Stokes and anti-Stokes sidebands, resulting in a preferential conversion to the first few Stokes lines, accompanied by a significant reduction in the Raman gain due to collisions with gas molecules. Here we report that, provided the dispersion can be precisely controlled, the effective Raman gain in a gas-filled hollow-core photonic crystal fiber can actually be significantly enhanced when a buffer gas is added. This counterintuitive behavior occurs when the nonlinear coupling between the interacting fields is strong and can result in a performance similar to that of a pure Raman-active gas, but at a much lower total gas pressure, allowing competing effects such as Raman backscattering to be suppressed. We report high modal purity in all the emitted sidebands, along with anti-Stokes conversion efficiencies as high as 5% in the visible and 2% in the ultraviolet. This new class of gas-based waveguide device, which allows the nonlinear optical response to be beneficially pressure-tuned by the addition of buffer gases, may find important applications in laser science and spectroscopy.
Mid-infrared dispersive wave generation in gas-filled photonic crystal fibre by transient ionization-driven changes in dispersion
F. Koettig,
D. Novoa,
F. Tani,
M. C. Guenendi,
M. Cassataro,
J. C. Travers,
P. St. J. Russell
Gas-filled hollow-core photonic crystal fibre is being used to generate ever wider super-continuum spectra, in particular via dispersive wave emission in the deep and vacuum ultraviolet, with a multitude of applications. Dispersive waves are the result of nonlinear transfer of energy from a self-compressed soliton, a process that relies crucially on phase-matching. It was recently predicted that, in the strong-field regime, the additional transient anomalous dispersion introduced by gas ionization would allow phase-matched dispersive wave generation in the mid-infrared-something that is forbidden in the absence of free electrons. Here we report the experimental observation of such mid-infrared dispersive waves, embedded in a 4.7-octave-wide supercontinuum that uniquely reaches simultaneously to the vacuum ultraviolet, with up to 1.7W of total average power.
High average power and single-cycle pulses from a mid-IR optical parametric chirped pulse amplifier
Ugaitz Elu,
Matthias Baudisch,
Hugo Pires,
Francesco Tani,
Michael H. Frosz,
Felix Koettig,
Alexey Ermolov,
Philip St J. Russell,
Jens Biegert
In attosecond and strong-field physics, the acquisition of data in an acceptable time demands the combination of high peak power with high average power. We report a 21 W mid-IR optical parametric chirped pulse amplifier (OPCPA) that generates 131 mu J and 97 fs (sub-9-cycle) pulses at a 160 kHz repetition rate and at a center wavelength of 3.25 mu m. Pulse-to-pulse stability of the carrier envelope phase (CEP)-stable output is excellent with a 0.33% rms over 288 million pulses (30 min) and compression close to a single optical cycle was achieved through soliton self-compression inside a gas-filled mid-IR antiresonant-guiding photonic crystal fiber. Without any additional compression device, stable generation of 14.5 fs (1.35-optical-cycle) pulses was achieved at an average power of 9.6 W. The resulting peak power of 3.9 GW in combination with the near-single-cycle duration and intrinsic CEP stability makes our OPCPA a key-enabling technology for the next generation of extreme photonics, strong-field attosecond research, and coherent x-ray science. (C) 2017 Optical Society of America
Fresnel-Reflection-Free Self-Aligning Nanospike Interface between a Step-Index Fiber and a Hollow-Core Photonic-Crystal-Fiber Gas Cell
Riccardo Pennetta,
Shangran Xie,
Frances Lenahan,
Manoj Mridha,
David Novoa,
Philip St. J. Russell
We report a fully integrated interface delivering efficient, reflection-free, single-mode, and self-aligned coupling between a step-index fiber and a gas-filled hollow-core photonic crystal fiber. The device offers a universal solution for interfacing solid and hollow cores and can be sealed to allow operation either evacuated or at high pressure. Stimulated Raman scattering and molecular modulation of light are demonstrated in a H-2-filled hollow-core photonic crystal fiber using the device.
Extremely broadband single-shot cross-correlation frequency-resolved optical gating using a transient grating as gate and dispersive element
H. Valtna-Lukner,
F. Belli,
A. Ermolov,
F. Koettig,
K. F. Mak,
F. Tani,
J. C. Travers,
P. St. J. Russell
REVIEW OF SCIENTIFIC INSTRUMENTS
88
(7)
073106
(2017)
| Journal
Across-correlation frequency-resolved optical gating (FROG) concept, potentially suitable for characterizing few or sub-cycle pulses in a single shot, is described in which a counter-propagating transient grating is used as both the gate and the dispersive element in a FROG spectrometer. An all-reflective setup, which can operate over the whole transmission range of the nonlinear medium, within the sensitivity range of the matrix sensor, is also proposed, and proof-of-principle experiments for the ultraviolet and visible-to-near-infrared spectral ranges are reported. Published by AIP Publishing.
Free space excitation of coupled Anderson-localized modes in photonic
crystal waveguides with polarization tailored beam
Ali Mahdavi,
Paul Roth,
Jolly Xavier,
Taofiq K. Paraiso,
Peter Banzer,
Frank Vollmer
We experimentally demonstrate free space excitation of coupled Anderson-localized modes in photonic crystal (PhC) line-defect waveguides (W1) with polarization tailored beams. The corresponding light beam is tightly focused on a pristine W1, and out-of-plane scattering is imaged. By integrating the scattering spectra along the guide, at the W1 modal cut-off, Anderson-localized cavities are observed due to residual W1 fabrication-disorder. Their spectral lines exhibit high quality Q factors up to 2 x 10(5). The incident beam polarization and scattering intensities of the localized modes characterize the efficiency of free-space coupling. The coupling is studied for linearly and radially polarized input beams and for different input coupling locations along the W1 guide. The proposed coupling scheme is particularly attractive for excitation of PhC waveguide modes and Anderson-localized cavities by beam steering and scanning microscopy for sensing applications. Published by AIP Publishing.
Nonlinear-Photonics Devices on the Basis of the Coherent Interaction of Optical Radiation with Resonant Media (a Review)
R. M. Arkhipov,
M. V. Arkhipov,
A. V. Pakhomov,
I. Babushkin,
N. N. Rosanov
OPTICS AND SPECTROSCOPY
122
(6)
949-954
(2017)
| Journal
We have examined examples of nonlinear-photonics devices that are based on the coherent interaction of light with matter. Such interaction takes place if the duration of a light pulse is shorter than the relaxation times T-1 and T-2 in a resonant medium and if the strength of the light field is so high that Rabi oscillations arise. Theoretical analysis shows that these systems have a number of advantages compared to similar devices that operate under incoherent interaction conditions of light with matter.
Generation of unipolar pulses in nonlinear media
R. M. Arkhipov,
A. V. Pakhomov,
M. V. Arkhipov,
I. Babushkin,
Yu. A. Tolmachev,
N. N. Rosanov
Methods recently proposed for generating unipolar pulses in nonlinear media in terahertz and optical electromagnetic ranges are reviewed. Such pulses have nonzero "electric area" (time integral of the field strength over the entire duration of a pulse) and, correspondingly, a significant component of the field with zero frequency, thus exhibiting quasistatic properties. Effective generation of unipolar pulses would allow, e.g., transferring mechanical momentum to charged particles and, thereby, controlling the motion of wave packets of matter, which can be useful for compact accelerators of charged particles and for other applications.
acoustic sensor, with the ability to detect and retrieve actual temporal waveforms of multiple vibration events that occur simultaneously at different positions along the fiber. The system is realized via a dual-pulse phase-sensitive optical time-domain reflectometry, and the actual waveform is retrieved by heterodyne phase demodulation. Experimental results show that the system has a background noise level as low as 8.91 x 10(-4) rad/root Hz with a demodulation signal-to-noise ratio of 49.17 dB at 1 kHz, and can achieve a dynamic range of similar to 60 dB at 1 kHz (0.1 to 104 rad) for phase demodulation, as well as a detection frequency range from 20 Hz to 25 kHz. (C) 2017 Optical Society of America
Broadband high-resolution multi-species CARS in gas-filled hollow-core photonic crystal fiber
Barbara M. Trabold,
Robert J. R. Hupfer,
Amir Abdolvand,
Philip St. J. Russell
We report the use of coherent anti-Stokes Raman spectros-copy (CARS) in gas-filled hollow-core photonic crystal fiber (HC-PCF) for trace gas detection. The long optical path-lengths yield a 60 dB increase in the signal level compared with free-space arrangements. This enables a relatively weak supercontinuum (SC) to be used as Stokes seed, along with a ns pump pulse, paving the way for broadband (> 4000 cm(-1)) single-shot CARS with an unprecedented resolution of similar to 100 MHz. A kagome-style HC-PCF provides broadband guidance, and, by operating close to the pressure-tunable zero dispersion wavelength, we can ensure simultaneous phase-matching of all gas species. We demonstrate simultaneous measurement of the concentrations of multiple trace gases in a gas sample introduced into the core of the HC-PCF. (C) 2017 Optical Society of America
Generation of unipolar half-cycle pulses via unusual reflection of a single-cycle pulse from an optically thin metallic or dielectric layer
M. V. Arkhipov,
R. M. Arkhipov,
A. V. Pakhomov,
I. V. Babushkin,
A. Demircan,
U. Morgner,
N. N. Rosanov
We propose a strikingly simple method to form approximately unipolar half-cycle optical pulses via reflection of a single-cycle optical pulse from a thin flat metallic or dielectric layer. Unipolar pulses in reflection arise due to specifics of one-dimensional pulse propagation. Namely, we show that the field emitted by the layer is proportional to the velocity of the oscillating charges in the medium, instead of their acceleration. Besides, the oscillation velocity of the charges can be forced to keep a constant sign throughout the pulse duration. That is, reflection of ultrashort pulses from broad-area layers with nanometer-scale thickness can be very different from the common reflection in the case of longer pulses and thicker layers. This suggests a possibility of unusual transformations of few-cycle light pulses in completely linear optical systems. (C) 2017 Optical Society of America
Analytical formulation for the bend loss in single-ring hollow-core photonic crystal fibers
Michael H. Frosz,
Paul Roth,
Mehmet C. Guenendi,
Philip St. J. Russell
Understanding bend loss in single-ring hollow-core photonic crystal fibers (PCFs) is becoming of increasing importance as the fibers enter practical applications. While purely numerical approaches are useful, there is a need for a simpler analytical formalism that provides physical insight and can be directly used in the design of PCFs with low bend loss. We show theoretically and experimentally that a wavelength-dependent critical bend radius exists below which the bend loss reaches a maximum, and that this can be calculated from the structural parameters of a fiber using a simple analytical formula. This allows straightforward design of single-ring PCFs that are bend-insensitive for specified ranges of bend radius and wavelength. It also can be used to derive an expression for the bend radius that yields optimal higher-order mode suppression for a given fiber structure. (C) 2017 Chinese Laser Press
Photochemistry in a soft-glass single-ring hollow-core photonic crystal fibre
Ana M. Cubillas,
Xin Jiang,
Tijmen G. Euser,
Nicola Taccardi,
Bastian J. M. Etzold,
Peter Wasserscheid,
Philip St. J. Russell
A hollow-core photonic crystal fibre (HC-PCF), guided by photonic bandgap effects or anti-resonant reflection, offers strong light confinement and long photochemical interaction lengths in a microscale channel filled with a solvent of refractive index lower than that of glass (usually fused silica). These unique advantages have motivated its recent use as a highly efficient and versatile microreactor for liquid-phase photochemistry and catalysis. In this work, we use a single-ring HC-PCF made from a high-index soft glass, thus enabling photochemical experiments in higher index solvents. The optimized light-matter interaction in the fibre is used to strongly enhance the reaction rate in a proof-of-principle photolysis reaction in toluene.
Kontakt
Bitte richten Sie forschungsbezogene Anfragen an philip.russell@mpl.mpg.de und allgemeine Anfragen an Bettina Schwender:
Max-Planck-Institut für die Physik des Lichts Staudtstr. 2 91058 Erlangen
