We present a simple refractive index sensor based on a step-index fiber with a hollow micro-channel running parallel to its core. This channel becomes waveguiding when filled with a liquid of index greater than silica, causing sharp dips to appear in the transmission spectrum at wavelengths where the glass-core mode phase-matches to a mode of the liquid-core. The sensitivity of the dip-wavelengths to changes in liquid refractive index is quantified and the results used to study the dynamic flow characteristics of fluids in narrow channels. Potential applications of this fiber microstructure include measuring the optical properties of liquids, refractive index sensing, biophotonics and studies of fluid dynamics on the nanoscale. (C) 2011 Optical Society of America
Real-time determination of laser beam quality by modal decomposition
Oliver A. Schmidt,
Christian Schulze,
Daniel Flamm,
Robert Bruening,
Thomas Kaiser,
Siegmund Schroeter,
Michael Duparre
We present a real-time method to determine the beam propagation ratio M-2 of laser beams. The all-optical measurement of modal amplitudes yields M-2 parameters conform to the ISO standard method. The experimental technique is simple and fast, which allows to investigate laser beams under conditions inaccessible to other methods. (C) 2011 Optical Society of America
Asymptotic Analysis of Flow Processes at Drawing of Single Optical
Microfibres
Giovanni Luzi,
Philipp Epple,
Michael Scharrer,
Ken Fujimoto,
Cornelia Rauh,
Antonio Delgado
INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING
9
A65
(2011)
Microstructured optical fibres (i.e. fibres that contain holes) have assumed a high profile in recent years, and given rise to many novel optical devices. The problem of manufacturing such fibres by heating and then drawing a preform is considered for both the cases of annular microfibres and annular capillaries. A fluid-mechanics model suggested in literature that uses asymptotic analysis based on the small aspect ratio of capillaries is analysed and revised. The leading-order equations are examined in some asymptotic limits, many of which give valuable practical information about the control parameters that influence the drawing process. Additionally, the solution obtained for a single capillary provides a suitable basis for describing more complicated fibre structures.
Bandgap guidance in hybrid chalcogenide-silica photonic crystal fibers
Nicolai Granzow,
Patrick Uebel,
Markus A. Schmidt,
Andrey S. Tverjanovich,
Lothar Wondraczek,
Philip St J. Russell
OPTICS LETTERS
36
(13)
2432-2434
(2011)
We report a hybrid chalcogenide-silica photonic crystal fiber made by pressure-assisted melt-filling of molten glass. Photonic bandgap guidance is obtained at a silica core placed centrally in a hexagonal array of continuous centimeters-long chalcogenide strands with diameters of 1.45 mu m. In the passbands of the cladding, when the transmission through the silica core is very weak, the chalcogenide strands light up with distinct modal patterns corresponding to Mie resonances. In the spectral regions between these passbands, strong bandgap guidance is observed, where the silica core transmission loss is 60 dB/cm lower. The pressure-assisted fabrication approach opens up new ways of integrating sophisticated glass-based devices into optical fiber circuitry with potential applications in supercontinuum generation, magneto-optics, wavelength selective devices, and rare-earth-doped amplifiers with high gain per unit length. (C) 2011 Optical Society of America
Interfacial reactions between tellurite melts and silica during the
production of microstructured optical devices
N. Da,
A. A. Enany,
N. Granzow,
M. A. Schmidt,
P. St. J. Russell,
L. Wondraczek
JOURNAL OF NON-CRYSTALLINE SOLIDS
357
(6-7)
1558-1563
(2011)
| Journal
Interfacial reactions between silica glass and tellurite melts were studied under confined conditions in the temperature regime of 400-700 degrees C, applying two different sampling techniques: isothermal heat-treatment of a several micrometer thick tellurite film, confined in a silica/tellurite/silica sandwich, and capillary filling of tellurite melts into silica microcapillaries. The sandwich technique provides detailed ex situ insights on the interface chemistry, microstructure and diffusion after given treatment times and temperatures. Data on dynamic viscosity, surface tension, wetting behaviour and eventual scaling effects was obtained from the capillary filling technique. For temperatures > 500 degrees C, silica is completely wet by the considered tellurite melts. At T > 600 degrees C and for a treatment time of 20 min or longer, cationic diffusion of Na(+) and Te(4+) into the silica substrate occurs to a depth of several micrometers. At the same time, the tellurite melt attacks the silica surface, leading to the formation of a stationary silica-tellurite reaction layer and silica dissolution. Dissolved silica was observed to re-precipitate from the tellurite melt by liquid-liquid phase separation. In the early reaction stages, as a result of alkali diffusion into the silica substrate, beta-quartz crystallizes at the interface (what can be avoided by using alkali-free filling glasses). Obtained data set the boundary conditions for the generation of tellurite-silica all-solid fiber waveguides by melt infiltration of silica photonic crystal fibers or microcapillaries. (C) 2011 Elsevier B.V. All rights reserved.
Complex Faraday Rotation in Microstructured Magneto-optical Fiber
Waveguides
Markus A. Schmidt,
Lothar Wondraczek,
Ho W. Lee,
Nicolai Granzow,
Ning Da,
Philip St. J. Russell
Magneto-optical glasses are of considerable current interest, primarily for applications in fiber circuitry, optical isolation, all-optical diodes, optical switching and modulation. While the benchmark materials are still crystalline, glasses offer a variety of unique advantages, such as very high rare-earth and heavy-metal solubility and, in principle, the possibility of being produced in fiber form. In comparison to conventional fiber-drawing processes, pressure-assisted melt-filling of microcapillaries or photonic crystal fibers with magneto-optical glasses offers an alternative route to creating complex waveguide architectures from unusual combinations of glasses. For instance, strongly diamagnetic tellurite or chalcogenide glasses with high refractive index can be combined with silica in an all-solid, microstructured waveguide. This promises the implementation of as-yet-unsuitable but strongly active glass candidates as fiber waveguides, for example in photonic crystal fibers.
Structural analysis of photonic crystal fibers by side scattering of
laser light
L. Y. Zang,
T. G. Euser,
M. S. Kang,
M. Scharrer,
P. St. J. Russell
OPTICS LETTERS
36
(9)
1668-1670
(2011)
A side-scattering technique for investigating the inner microstructure of photonic crystal fibers (PCFs) is reported. Multiple scattering is reduced by filling the hollow PCF channels with index-matching fluid. The scattered signal is measured for fixed angles of incidence and detection while the fiber is rotated. A pattern of peaks, unique to each PCF, whether solid or hollow core, correlates closely with the symmetry planes of the PCF structure. As an example of the technique, the twist profile of a structural rocking filter is directly measured. (C) 2011 Optical Society of America
Femtosecond Nonlinear Fiber Optics in the Ionization Regime
P. Hoelzer,
W. Chang,
J. C. Travers,
A. Nazarkin,
J. Nold,
N. Y. Joly,
M. F. Saleh,
F. Biancalana,
P. St. J. Russell
By using a gas-filled kagome-style photonic crystal fiber, nonlinear fiber optics is studied in the regime of optically induced ionization. The fiber offers low anomalous dispersion over a broad bandwidth and low loss. Sequences of blueshifted pulses are emitted when 65 fs, few-microjoule pulses, corresponding to high-order solitons, are launched into the fiber and undergo self-compression. The experimental results are confirmed by numerical simulations which suggest that free-electron densities of similar to 10(17) cm(-3) are achieved at peak intensities of 10(14) W/cm(2) over length scales of several centimeters.
Influence of ionization on ultrafast gas-based nonlinear fiber optics
W. Chang,
A. Nazarkin,
J. C. Travers,
J. Nold,
P. Hoelzer,
N. Y. Joly,
P. St. J. Russell
We numerically investigate the effect of ionization on ultrashort high-energy pulses propagating in gas-filled kagome-lattice hollow-core photonic crystal fibers by solving an established uni-directional field equation. We consider the dynamics of two distinct regimes: ionization induced blue-shift and resonant dispersive wave emission in the deep-UV. We illustrate how the system evolves between these regimes and the changing influence of ionization. Finally, we consider the effect of higher ionization stages. (C) 2011 Optical Society of America
Bubble formation in basalt-like melts
Martin Jensen,
Yuanzheng Yue,
Ralf Keding
GLASS TECHNOLOGY-EUROPEAN JOURNAL OF GLASS SCIENCE AND TECHNOLOGY PART A
52
(4)
127-135
(2011)
The effect of the melting temperature on bubble size and bubble formation in an iron bearing calcium aluminosilicate melt is studied by means of in-depth images acquired by optical microscopy. The bubble size distribution and the total bubble volume are determined by counting the number of bubbles and their diameter. The variation in melting temperature has little influence on the overall bubble volume. However, the size distribution of the bubbles varies with the melting temperature. When the melt is slowly cooled, the bubble volume increases, implying decreased solubility of the gaseous species. Mass spectroscopy analysis of gases liberated during heating of the glass reveals that small bubbles contain predominantly CH4, CO and CO2, whereas large bubbles contain N-2, SO2 and H2S. The methodology utilised in this work can, besides mapping the bubbles in a glass, be applied to shed light on the sources of bubble formation.
Pressure-assisted melt-filling and optical characterization of Au
nano-wires in microstructured fibers
H. W. Lee,
M. A. Schmidt,
R. F. Russell,
N. Y. Joly,
H. K. Tyagi,
P. Uebel,
P. St. J. Russell
We report a novel splicing-based pressure-assisted melt-filling technique for creating metallic nanowires in hollow channels in microstructured silica fibers. Wires with diameters as small as 120 nm (typical aspect ration 50:1) could be realized at a filling pressure of 300 bar. As an example we investigate a conventional single-mode step-index fiber with a parallel gold nanowire (wire diameter 510 nm) running next to the core. Optical transmission spectra show dips at wavelengths where guided surface plasmon modes on the nanowire phase match to the glass core mode. By monitoring the side-scattered light at narrow breaks in the nanowire, the loss could be estimated. Values as low as 0.7 dB/mm were measured at resonance, corresponding to those of an ultra-long-range eigenmode of the glass-core/nanowire system. By thermal treatment the hollow channel could be collapsed controllably, permitting creation of a conical gold nanowire, the optical properties of which could be monitored by side-scattering. The reproducibility of the technique and the high optical quality of the wires suggest applications in fields such as nonlinear plasmonics, near-field scanning optical microscope tips, cylindrical polarizers, optical sensing and telecommunications. (C) 2011 Optical Society of America
Ultrafast nonlinear optics in gas-filled hollow-core photonic crystal
fibers [Invited]
John C. Travers,
Wonkeun Chang,
Johannes Nold,
Nicolas Y. Joly,
Philip St. J. Russell
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
28
(12)
A11-A26
(2011)
We review the use of hollow-core photonic crystal fibers (PCFs) in the field of ultrafast gas-based nonlinear optics, including recent experiments, numerical modeling, and a discussion of future prospects. Concentrating on broadband guiding kagome-style hollow-core PCF, we describe its potential for moving conventional nonlinear fiber optics both into extreme regimes-such as few-cycle pulse compression and efficient deep ultraviolet wavelength generation-and into regimes hitherto inaccessible, such as single-mode guidance in a photoionized plasma and high-harmonic generation in fiber. (C) 2011 Optical Society of America
Optofluidic immobility of particles trapped in liquid-filled hollow-core
photonic crystal fiber
We study the conditions under which a particle, laser-guided in a vertically-oriented hollow-core photonic crystal fiber filled with liquid, can be kept stationary against a microfluidic counter-flow. An immobility parameter-the fluid flow rate required to immobilize a particle against the radiation force produced by unit guided optical power-is introduced to quantify the conditions under which this occurs, including radiation, viscous and gravity forces. Measurements show that this parameter depends strongly on the ratio of particle radius a to core radius R, peaking at an intermediate value of a/R. The results follow fairly well the theoretical estimates of the optical (calculated approximately using a ray optics approach) and numerically simulated drag forces. We suggest that the system has potential applications in, e.g., measurement of the diameter, refractive index and density of particles, synthesis and biomedical research. (C) 2011 Optical Society of America
Reconfigurable light-driven opto-acoustic isolators in photonic crystal
fibre
Dynamic optical isolation with all-optical switching capability is in great demand in advanced optical communications and all-optical signal processing systems. Most conventional optical isolators rely on Faraday rotation and are realized using micro/nanofabrication techniques, but it is not always straightforward to incorporate magneto-optical crystals into these compact systems. Here, we report the experimental demonstration of a reconfigurable all-optical isolator based on optical excitation of a gigahertz guided acoustic mode in a micrometre-sized photonic crystal fibre core. This device has remarkable advantages over its passive counterparts, including a large dynamic range of isolation, fast switching capability and reversibility, which provide new functionality that is useful in various types of all-optical systems. Devices based on similar physical principles could also be realized in CMOS-compatible silicon on-chip platforms.
Single-mode hollow-core photonic crystal fiber made from soft glass
X. Jiang,
T. G. Euser,
A. Abdolvand,
F. Babic,
F. Tani,
N. Y. Joly,
J. C. Travers,
P. St J. Russell
We demonstrate the first soft-glass hollow core photonic crystal fiber. The fiber is made from a high-index lead-silicate glass (Schott SF6, refractive index 1.82 at 500 nm). Fabricated by the stack-and-draw technique, the fiber incorporates a 7-cell hollow core embedded in a highly uniform 6-layer cladding structure that resembles a kagome-like lattice. Effective single mode guidance of light is observed from 750 to 1050 nm in a large mode area (core diameter similar to 30 mu m) with a low loss of 0.74 dB/m. The underlying guidance mechanism of the fiber is investigated using finite element modeling. The fiber is promising for applications requiring single mode guidance in a large mode area, such as particle guidance, fluid and gas filled devices. (C) 2011 Optical Society of America
Birefringence and dispersion of cylindrically polarized modes in
nanobore photonic crystal fiber
T. G. Euser,
M. A. Schmidt,
N. Y. Joly,
C. Gabriel,
C. Marquardt,
L. Y. Zang,
M. Foertsch,
P. Banzer,
A. Brenn, et al.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
28
(1)
193-198
(2011)
| Journal
We demonstrate experimentally and theoretically that a nanoscale hollow channel placed centrally in the solid-glass core of a photonic crystal fiber strongly enhances the cylindrical birefringence (the modal index difference between radially and azimuthally polarized modes). Furthermore, it causes a large split in group velocity and group velocity dispersion. We show analytically that all three parameters can be varied over a wide range by tuning the diameters of the nanobore and the core. (C) 2010 Optical Society of America
An azimuthally polarizing photonic crystal fibre with a central gold
nanowire
Patrick Uebel,
Markus A. Schmidt,
Michael Scharrer,
Philip St J. Russell
An air-silica photonic crystal fibre with a gold nanowire at core centre is shown to support a low-loss azimuthally polarized mode. Since all the other modes have very high attenuation, the fibre effectively supports only this mode, acting as a single-polarization fibre with an extinction ratio >20 dB cm(-1) over a broad range of wavelengths (550-1650 nm in the device reported). It can be used as an effective azimuthal mode filter.
Multi-mJ carrier envelope phase stabilized few-cycle pulses generated by
a tabletop laser system
A. Anderson,
F. Luecking,
T. Prikoszovits,
M. Hofer,
Z. Cheng,
C. C. Neacsu,
M. Scharrer,
S. Rammler,
P. St J. Russell, et al.
A compact system for the generation of few-cycle multi-mJ Carrier Envelope Phase (CEP) stabilized pulses is presented. At the output 1.9 mJ, 5.7 fs pulses were achieved after hollow fiber compression (HFC) of 5 mJ, 25 fs circularly-polarized pulses from a Ti:sapphire multipass chirped pulse amplifier (CPA). Polarization control of the generated pulses was done using all reflective phase retarders which can be nearly arbitrarily scaled for increasing energies. The CEP noise from the amplifier system is shown to be 190 mrad rms over a period of more than 7 hours. The full system, i.e., oscillator, amplifier, CEP stabilization, and HFC is compact enough to fit on a standard optical table.
Fiber Transport of Spatially Entangled Photons
W. Loeffler,
T. G. Euser,
E. R. Eliel,
M. Scharrer,
P. St J. Russell,
J. P. Woerdman
Entanglement in the spatial degrees of freedom of photons is an interesting resource for quantum information. For practical distribution of such entangled photons, it is desirable to use an optical fiber, which in this case has to support multiple transverse modes. Here we report the use of a hollow-core photonic crystal fiber to transport spatially entangled qubits.
Theory of Photoionization-Induced Blueshift of Ultrashort Solitons in
Gas-Filled Hollow-Core Photonic Crystal Fibers
Mohammed F. Saleh,
Wonkeun Chang,
Philipp Hoelzer,
Alexander Nazarkin,
John C. Travers,
Nicolas Y. Joly,
Philip St. J. Russell,
Fabio Biancalana
We show theoretically that the photoionization process in a hollow-core photonic crystal fiber filled with a Raman-inactive noble gas leads to a constant acceleration of solitons in the time domain with a continuous shift to higher frequencies, limited only by ionization loss. This phenomenon is opposite to the well-known Raman self-frequency redshift of solitons in solid-core glass fibers. We also predict the existence of unconventional long-range nonlocal soliton interactions leading to spectral and temporal soliton clustering. Furthermore, if the core is filled with a Raman-active molecular gas, spectral transformations between redshifted, blueshifted, and stabilized solitons can take place in the same fiber.
Supercontinuum generation in chalcogenide-silica step-index fibers
N. Granzow,
S. P. Stark,
M. A. Schmidt,
A. S. Tverjanovich,
L. Wondraczek,
P. St. J. Russell
We explore the use of a highly nonlinear chalcogenide-silica waveguide for supercontinuum generation in the near infrared. The structure was fabricated by a pressure-assisted melt-filling of a silica capillary fiber (1.6 mu m bore diameter) with Ga4Ge21Sb10S65 glass. It was designed to have zero group velocity dispersion (for HE11 core mode) at 1550 nm. Pumping a 1 cm length with 60 fs pulses from an erbium-doped fiber laser results in the generation of octave-spanning supercontinuum light for pulse energies of only 60 pJ. Good agreement is obtained between the experimental results and theoretical predictions based on numerical solutions of the generalized nonlinear Schrodinger equation. The pressure-assisted melt-filling approach makes it possible to realize highly nonlinear devices with unusual combinations of materials. For example, we show numerically that a 1 cm long As2S3:silica step-index fiber with a core diameter of 1 mu m, pumped by 60 fs pulses at 1550 nm, would generate a broadband supercontinuum out to 4 mu m. (C) 2011 Optical Society of America
Doppler velocimetry on microparticles trapped and propelled by laser
light in liquid-filled photonic crystal fiber
M. K. Garbos,
T. G. Euser,
O. A. Schmidt,
S. Unterkofler,
P. St. J. Russell
OPTICS LETTERS
36
(11)
2020-2022
(2011)
Laser Doppler velocimetry is used to measure very accurately the velocity and position of a microparticle propelled and guided by laser light in liquid-filled photonic crystal fiber. Periodic variations in particle velocity are observed that correlate closely with modal beating between the two lowest order guided fiber modes. (C) 2011 Optical Society of America
14 GHz visible supercontinuum generation: calibration sources for
astronomical spectrographs
S. P. Stark,
T. Steinmetz,
R. A. Probst,
H. Hundertmark,
T. Wilken,
T. W. Haensch,
Th. Udem,
P. St. J. Russell,
R. Holzwarth
We report the use of a specially designed tapered photonic crystal fiber to produce a broadband optical spectrum covering the visible spectral range. The pump source is a frequency doubled Yb fiber laser operating at a repetition rate of 14 GHz and emitting sub-5 pJ pulses. We experimentally determine the optimum core diameter and achieve a 235 nm broad spectrum. Numerical simulations are used to identify the underlying mechanisms and explain spectral features. The high repetition rate makes this system a promising candidate for precision calibration of astronomical spectrographs. (C) 2011 Optical Society of America
Gain Enhancement by Dielectric Horns in the Terahertz Band
Belen Andres-Garcia,
Enrique Garcia-Munoz,
Sebastian Bauerschmidt,
Sascha Preu,
Stefan Malzer,
Gottfried H. Doehler,
Lijun Wang,
Daniel Segovia-Vargas
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
59
(9)
3164-3170
(2011)
| Journal
A new geometry for the design of antennas in the Terahertz band is presented. The structure is based on a horn antenna etched in the substrate and fed with a planar printed antenna used for generation of terahertz radiation, designed for the 200 GHz to 3 THz range. For the proposed antenna, the energy distribution through the substrate is reduced towards an increase in the gain of the system, at least, 8 dB in a 1: 10 bandwidth. The structure has been measured showing the expected behavior in the low band.
Comparison Between an Analytical Asymptotic Fiber Drawing Model With
Full Navier-Stokes Solution Taking Into Account the Effects of Inner
Pressure and Surface Tension
Giovanni Luzi,
Philipp Epple,
Michael Scharrer,
Ken Fujimoto,
Cornelia Rauh,
Antonio Delgado
JOURNAL OF LIGHTWAVE TECHNOLOGY
29
(11)
1638-1646
(2011)
| Journal
A fluid-mechanics model that make use of asymptotic analysis based on small aspect ratio of capillaries has been compared with the full 3-D set of the N.-St. equations, for modelling the fabrication of capillary tubes. The final asymptotic equations are solved numerically and then compared with the N.-St. solutions, obtained with a commercial finite elements solver. The present paper focuses on the comparison of the solution of the two methods taking into account the effects of surface tension and internal hole pressure, since those are of essential importance during drawing. It is shown that the analytical asymptotic method delivers reliable results for practical applications, as long as the inner pressure or the temperature does not exceed too high values.
Entangling Different Degrees of Freedom by Quadrature Squeezing
Cylindrically Polarized Modes
C. Gabriel,
A. Aiello,
W. Zhong,
T. G. Euser,
N. Y. Joly,
P. Banzer,
M. Foertsch,
D. Elser,
U. L. Andersen, et al.
Quantum systems such as, for example, photons, atoms, or Bose-Einstein condensates, prepared in complex states where entanglement between distinct degrees of freedom is present, may display several intriguing features. In this Letter we introduce the concept of such complex quantum states for intense beams of light by exploiting the properties of cylindrically polarized modes. We show that already in a classical picture the spatial and polarization field variables of these modes cannot be factorized. Theoretically it is proven that by quadrature squeezing cylindrically polarized modes one generates entanglement between these two different degrees of freedom. Experimentally we demonstrate amplitude squeezing of an azimuthally polarized mode by exploiting the nonlinear Kerr effect in a specially tailored photonic crystal fiber. These results display that such novel continuous-variable entangled systems can, in principle, be realized.
Nonlinear wavelength conversion in photonic crystal fibers with three
zero-dispersion points
S. P. Stark,
F. Biancalana,
A. Podlipensky,
P. St. J. Russell
In this theoretical study, we show that a simple endlessly single-mode photonic crystal fiber can be designed to yield, not just two, but three zero-dispersion wavelengths. The presence of a third dispersion zero creates a rich phase-matching topology, enabling enhanced control over the spectral locations of the four-wave-mixing and resonant-radiation bands emitted by solitons and short pulses. The greatly enhanced flexibility in the positioning of these bands has applications in wavelength conversion, supercontinuum generation, and pair-photon sources for quantum optics.
Soliton Blueshift in Tapered Photonic Crystal Fibers
We show that solitons undergo a strong blueshift in fibers with a dispersion landscape that varies along the direction of propagation. The experiments are based on a small-core photonic crystal fiber, tapered to have a core diameter that varies continuously along its length, resulting in a zero-dispersion wavelength that moves from 731 nm to 640 nm over the transition. The central wavelength of a soliton translates over 400 nm towards a shorter wavelength. This is accompanied by strong emission of radiation into the UV and IR spectral regions. The experimental results are confirmed by numerical simulation.
Bright Spatially Coherent Wavelength-Tunable Deep-UV Laser Source Using
an Ar-Filled Photonic Crystal Fiber
N.Y. Joly,
J. Nold,
W. Chang,
P. Hoelzer,
A. Nazarkin,
G. K. L. Wong,
F. Biancalana,
P. St. J. Russell
We report on the spectral broadening of similar to 1 mu J 30 fs pulses propagating in an Ar-filled hollow-core photonic crystal fiber. In contrast with supercontinuum generation in a solid-core photonic crystal fiber, the absence of Raman and unique pressure-controlled dispersion results in efficient emission of dispersive waves in the deep-UV region. The UV light emerges in the single-lobed fundamental mode and is tunable from 200 to 320 nm by varying the pulse energy and gas pressure. The setup is extremely simple, involving <1 m of a gas-filled photonic crystal fiber, and the UV signal is stable and bright, with experimental IR to deep-UV conversion efficiencies as high as 8 %. The source is of immediate interest in applications demanding high spatial coherence, such as laser lithography or confocal microscopy.
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
