Ondrej Kitzler

Ondrej Kitzler
Macquarie University · Department of Physics and Astronomy

Doctor of Philosophy

About

77
Publications
12,122
Reads
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792
Citations
Additional affiliations
August 2014 - present
Macquarie University
Position
  • PostDoc Position
Description
  • Development of UV Cerium doped fluoride lasers in continuous wave and pulsed regime.
February 2013 - November 2013
Macquarie University
Position
  • Laboratory demonstrator manager
Description
  • Participating in demonstrating of experiments and managing other demonstrators. Marking labbooks.
February 2013 - November 2013
Macquarie University
Position
  • Tutorial assisting teacher
Description
  • Helping students solve tutorial problems. Marking tests.
Education
October 2010 - October 2014
Macquarie University
Field of study
  • Raman lasers
October 2008 - September 2010
Czech Technical University in Prague
Field of study
  • Laser Technology
September 2003 - September 2007
Czech Technical University in Prague
Field of study
  • Optoelectronics

Publications

Publications (77)
Article
We demonstrate a new, to the best of our knlowledge, cavity design for terahertz (THz) lasers based on stimulated polariton scattering (SPS). The design simplifies the angle tuning of these lasers, which require non-collinear cavity fields at fundamental and Stokes wavelengths to cross in an SPS crystal with adjustable crossing angle. A mirror shar...
Article
We report the direct generation of mode-locked pulses as short as 91 fs from the broad-bandwidth gain medium of LiCaAlF6 (Ce:LiCAF) by combining Kerr-lens mode locking with synchronous pumping. The latter of these schemes, and the broad bandwidth of Ce:LiCAF, resulted in dispersion tuning of wavelength via cavity length in the spectral region of 29...
Article
We present experimental results and modeling of continuous wave resonantly pumped Raman lasers. The first Stokes diamond Raman ring laser generated 0.6 W at 960 nm with an efficiency of 18%; the second Stokes laser generated 1.5 W at 1485 nm at 9% efficiency. The analytical model, extended to arbitrary Stokes orders, shows the importance of modelli...
Article
Intrinsic randomness in quantum systems is a vital resource for cryptography and other quantum information protocols. To date, randomizing macroscopic polarization states requires randomness from an external source, which is then used to modulate the polarization e.g. for quantum key-distribution protocols. Here, we present a Raman-based device for...
Article
We report experimental observations of thermal lens effects in a diamond Raman laser operating up to 1.1 kW output power in a quasi- steady-state regime. Measured changes in the output beam parameters as a function of output power, including beam quality factor and beam divergence after a fixed focusing lens, are compared to modelling enabling us t...
Preprint
We demonstrate the generation of coherent Stokes pulses with randomized linear-polarization in diamond, when the pump wave-vector and linear polarization were oriented along the $[110]$ and $[1\bar{1}0]$ axes respectively. In this configuration the excitation of multiple Raman modes produces isotropic gain, preventing the Stokes pulse from acquirin...
Article
Full-text available
Brillouin lasers providing extremely narrow-linewidth are emerging as a powerful tool for microwave photonics, coherent communications, quantum processors, and spectroscopy. So far, laser performance and applications have been investigated for a handful of select materials and using guided-wave structures such as micro-resonators, optical fibers, a...
Article
Laser guide stars based on the mesospheric sodium layer are becoming increasingly important for applications that require correction of atmospheric scintillation effects. Despite several laser approaches being investigated to date, there remains great interest in developing lasers with the necessary power and spectral characteristics needed for bri...
Conference Paper
We explore a ring cavity continuous-wave diamond Raman laser with a tunable second Stokes output. We will characterize the laser operation at first and second Stokes and discuss the conditions of single longitudinal mode operation.
Conference Paper
We report the generation of Raman laser pulses in diamond with quantum-random polarisation, whereby laser pulses exhibit a coherent, well-defined, linear polarisation with an orientation that is random from pulse to pulse. © 2020 The Author(s)
Conference Paper
We show how pump and Stokes beams propagating within a {111} plane in diamond can always have polarization parallel to the highest gain direction. We propose amplifier and monolithic laser geometries benefiting from such designs.
Conference Paper
For the first time, a 22 W continuous-wave sodium guide star laser is demonstrated in an external standing-wave diamond Raman resonator with intra-cavity second harmonic generation.
Article
Polarisation eigenmode theory is well established for laser cavities in which the principal axes for gain and polarisation elements are parallel. Here we generalise the theory to include the case for gain axes at arbitrary angle to the birefringence, which is the case for Raman lasers based on cubic-class gain crystals that contain stress-induced b...
Article
An external cavity diamond Raman laser with 1.2 kW output power is demonstrated for durations 7 times longer than the thermal lens time constant. An 83% slope efficiency and a 53% optical-to-optical efficiency were obtained for conversion from a 1.06 μm pump to the 1.24 μm first Stokes. The pump had an M2 of 15, demonstrating that efficiency is mai...
Article
Full-text available
We report a novel cavity feedback mechanism for stabilizing single-longitudinal-mode (SLM) operation of diamond Raman lasers. Polarization-dependent Raman gain and in-grown stress birefringence in diamond were investigated as sources for Hänsch-Couillaud-type locking signals. The power range of SLM operation increased from 2.1 W to 7.2 W, compared...
Article
Single longitudinal mode (SLM) operation of a 620 nm diamond Raman laser is demonstrated in a standing-wave cavity that includes a second-harmonic generation element. Mode competition provided by the harmonic mixing is shown to greatly increase mode stability, in addition to the benefits of the spatial-hole-burning-free gain medium. Using a multi-l...
Article
We report a second Stokes diamond Raman laser at 1.49 μm capable of high power and large-scale-factor brightness enhancement. Using a quasi-continuous 1.06 μm pump of power 823 W (0.85% duty cycle) and M² up to 6.4, a maximum output power of 302 W was obtained with an M² = 1.1 providing an overall brightness enhancement factor of 6.0. The pulse len...
Preprint
Full-text available
The coherent interaction between optical and acoustic waves via stimulated Brillouin scattering (SBS) is a fundamental tool for manipulating light at GHz frequencies. Its narrowband and noise-suppressing characteristics have recently enabled microwave-photonic functionality in integrated devices based on chalcogenide glasses, silica and silicon. Di...
Article
Full-text available
Laser gain materials possessing high thermal conductivity and robust mechanical properties are key prerequisites for high power lasers. We show that diamond, when configured as a Raman laser, enables access to these and other extreme properties, providing an important new route to high power and high brightness beam generation. Recent achievements...
Article
High average power lasers with high beam quality are critical for emerging applications in industry and research for defense, materials processing, and space applications. However, overcoming thermal effects in the gain medium remains the key challenge for increasing laser brightness at high powers. Here we report a means for increasing the beam br...
Article
We report a high power quasi-continuous-wave (QCW) 620 nm laser from an external cavity diamond Raman laser utilizing intracavity frequency doubling in lithium triborate. Output power of 30 W for durations of 0.25 ms at 15% conversion e ciency was achieved with a beam quality factor M² = 1.1 from a free-running Nd:YAG pump laser of M² = 1.5. The cr...
Article
Stimulated Brillouin scattering (SBS), as one type of third-order nonlinear optics effect, is extensively exploited and rapidly developed in the field of lasers and optoelectronics. A large number of theoretical and experimental studies on SBS have been carried out in the past decades. Especially, the exploration of new SBS materials and new types...
Conference Paper
We report evidence for stimulated Brillouin scattering in diamond using an intense Raman-generated intracavity pump. Configurations are described for producing a single Stokes line and a Brillouin frequency comb containing up to the 22 orders spaced over 1.55 THz.
Conference Paper
Continuous-wave lasing in a free-space crystal Brillouin laser is demonstrated using CVD diamond. For a <111> polarized pump a threshold of 125 W is obtained, which corresponds to a gain coefficient of 60 cm/GW.
Conference Paper
We report a novel platform for Brillouin lasers in bulk, based on diamond. Continuous- wave lasing at 532.16-nm is demonstrated in a doubly-resonant ring cavity, from which we deduce a gain coefficient go = 60 cm/GW.
Conference Paper
We report a cavity stabilization scheme to enable single longitudinal mode operation from a diamond Raman laser at increased power. An output power of 7.2 W is demonstrated using a simple standing-wave laser cavity without the addition of frequency-selection elements.
Conference Paper
Full-text available
We report single-longitudinal-mode diamond Raman lasers at powers up to 7 W. Frequency conversion of an Yb-fiber-amplified DFB laser to the first- and second-order Stokes component generates tunable, frequency-stable output around 1.24 and 1.48 µm.
Article
We demonstrate a single-longitudinal-mode ring diamond Raman laser, pumped by a tunable single-mode Ti:sapphire laser. Two methods to achieving unidirectional operation have been demonstrated: increasing gain for one direction using a reinjecting mirror and increasing loss for one direction using sum frequency mixing in BBO. Both methods result in...
Conference Paper
We present our recent advances in the field of Raman frequency conversion using high-optical quality CVD-diamond. Different diamond Raman lasers were developed for efficiently generating multi-Watt output at specific wavelengths from the visible to the eye-safe spectral range, while single-frequency operation was accomplished by exploiting an intri...
Article
We report a quasi-continuous-wave external cavity Raman laser based on potassium yttrium tungstate (KYW). Laser output efficiency and spectrum are severely affected by the presence of high gain Raman modes of low frequency (< 250 cm−1) that are characteristic of this crystal class. Output spectra contained frequency combs spaced by the low frequenc...
Article
Full-text available
A fundamental advantage of lasers is their ability to produce a large number of photons in a single optical mode, yet this is achieved in only a minor fraction of devices due to the instability mechanism called spatial hole burning. Here, we exploit the spatial hole burning free nature of a stimulated scattering gain medium to demonstrate single lo...
Conference Paper
We report the spectral characteristics of an external cavity diamond Raman laser which is pumped by a narrow-linewidth cw laser near 1063 nm. A maximum output power of 14 W with diffraction limited beam quality was obtained with 38% conversion efficiency. Analysis of the spectral properties of the Stokes radiation showed single-longitudinal operati...
Article
Defect-induced stress has been mapped in optical-grade synthetic diamond (chemical vapor deposition grown, low nitrogen, low birefringence) using Metripol polarimetry, Mueller polarimetry, and Raman microscopy. Large circular retardance was observed in the 8 mm long h110i cut crystal with values up to 28° for some paths along the major axis. Metrip...
Article
Defect-induced stress has been mapped in optical-grade synthetic diamond (chemical vapor deposition grown, low nitrogen, low birefringence) using Metripol polarimetry, Mueller polarimetry, and Raman microscopy. Large circular retardance was observed in the 8 mm long h110i cut crystal with values up to 28° for some paths along the major axis. Metrip...
Conference Paper
Single-longitudinal mode operation of a continuous wave diamond Raman oscillator with power of 3.5 W is demonstrated. Frequency-stable and narrowband output which is tunable from 1238 to 1242 nm is obtained without intra-cavity frequency-selective elements.
Conference Paper
Full-text available
We report a first demonstration and characterization of a 289.9 nm continuous-wave (cw) Ce:LiCAF laser pumped by a cw 266 nm laser. This direct-UV laser has the potential to be tuned from 285–315 nm, and to generate few-fs pulses.
Article
Full-text available
We report birefringent tuning using single and multiple magnesium fluoride (MgF<sub>2</sub>) Brewster tuning plates in a mode-locked pumped continuous-wave Ce:LiCAF laser. Depending on the thickness of the MgF<sub>2</sub> plates used, continuous tuning over a range of up to 13 nm from 284.5 to 297.5 nm with a full width at half-maximum linewidth of...
Article
We report high-power frequency conversion of a Yb-doped fiber laser using a double-pass pumped external-cavity diamond Raman oscillator. Pumping with circular polarization is shown to be efficient while facilitating high-power optical isolation between the pump and Raman laser. We achieved continuous-wave average power of 154 W with a conversion ef...
Article
Full-text available
We report an analytical model describing power and efficiency of a 23 W quasi-continuous-wave diamond Raman laser. The model guides the optimization of the first Stokes output power as a function of resonator and crystal parameters. We show that, in the limit of a weak thermal lens, efficient operation requires strong focussing, low output coupling...
Conference Paper
The power and beam quality behavior of second-Stokes KGW and diamond external cavity Raman lasers at pump powers up to 40 W has been investigated. Severe thermally-induced effects are evident in the KGW Raman laser at high power levels whereas for diamond these are negligible. The diamond Raman laser generated a maximum of 16 W with conversion effi...
Conference Paper
Full-text available
We present an analytical steady-state model of an external cavity Raman laser. We use this model to optimise a quasi-cw pumped diamond Raman laser with 23 W of steady-state Stokes power in 30 ms pulses.
Conference Paper
Advances in synthesis of diamonds have provided a "new" material with properties that may enable massive increases in optical device capability. We review the development of diamond Raman lasers for enhancing laser brightness and extending wavelength range.
Article
Scientists are using high-purity synthetic diamonds to create novel devices that offer increased laser power, brightness and wavelength reach.
Article
Full-text available
Quasi-cw pumping is used to investigate the high-power characteristics of cw beam conversion in diamond Raman lasers (DRLs). We show that thermal gradients establish in DRLs at approximately 50 μs for a 100 μm pump beam diameter, and thus that the steady state for cw operation can be reached within the 100–300 μs pulse duration of conventional quas...
Article
Brightness enhancement in an external cavity diamond Raman laser designed for high power conversion of a neodymium (1064 nm) laser to the eye-safe spectral region is reported. Using a multimode input beam pulsed at 36 kHz pulse repetition frequency, 16.2 W with 40% overall conversion efficiency was obtained at the second Stokes wavelength of 1485 n...
Article
Full-text available
The transient thermal lens in a high-average power double metal tungstate Raman laser has been investigated. An external cavity potassium gadolinium tungstate (KGW) laser designed for second-Stokes output was burst-pumped with up to 46 W of average power at a pulse repetition rate of 38 kHz. At low duty-cycle, the laser generated up to 18 W of on-t...
Article
Full-text available
We report an investigation into a double metal tungstate Raman laser when pumped at elevated average powers. Potassium gadolinium tungstate (KGW) was placed in an external cavity configured for second-Stokes output and pumped at pulse repetition rate of 38 kHz with up to 46 W of average power. For output powers above 3 W, we observe preferential ex...
Conference Paper
Full-text available
We present experiment and modeling of extra-cavity diamond Raman laser performance. We model the Stokes output and threshold as a function of various parameters and discuss the impact of crystal birefringence on Stokes polarization.
Article
Efficient operation of a pulsed diamond Raman laser at output powers up to 14.5 W is reported. An external-cavity Raman resonator 2.5 cm long employing a low-loss CVD diamond 9.5 mm long generated first (1240 nm) and second (1485 nm) Stokes output powers of up to 3 W and 13 W respectively when pumped with a 30 W q-switched Nd:YVO4 laser with approx...
Conference Paper
This paper reports on an external-cavity diamond Raman laser of output power 14.5 W and quantum conversion efficiency 65%. The laser was pumped by a 30 W Q-switched Nd:YVO4 laser delivering 20 ns pulses at 36.5 kHz pulse repetition frequency. The laser threshold was 6.9 W. Up to 3 W was generated at 1240 nm and 13 W was generated at 1485 nm in the...
Conference Paper
Full-text available
In this paper, we report a characterization of an external cavity cw diamond Raman laser pumped by a single frequency fibre laser. The diamond was pumped using a seeded (linewidth ≈5 MHz) TEM00 mode linearly polarized Yb based fibre laser (IPG Photonics) operating at 1064 nm focused to a diameter of about 40 μm. The diamond faces were antireflectio...
Chapter
Introduction and Background Optical, Thermal, and Physical Properties of Diamond Diamond Raman Laser Development Extending the Capability of Raman Lasers Using Diamond Conclusions and Outlook Acknowledgments References
Article
The goal of our research is a compact Raman laser emitting short pulses with high energy and peak power in "eye-safe" region around wavelength 1.5 μm. We utilize intracavity conversion of giant pulses at wavelength 1.34 μm in a BaWO4 Raman crystal (18 mm long, AR coated). Required high energy and peak power was reached using a flash-lamp pumped Nd:...
Article
We report external cavity Raman lasers using a 9.5-mm-long low-loss CVD diamond pumped by a 35 W q-switched Nd:YVO4 laser with approximately 22 ns pulses at 36 kHz pulse repetition frequency. Two systems were investigated. The first demonstrated first and second Stokes simultaneously with more than 14.5 W of combined optical power. For an output co...
Article
Full-text available
We demonstrate continuous-wave (cw) operation of a diamond Raman laser at 1240 nm in an external cavity configuration. The output power increased linearly with pump power with a 49.7% slope efficiency and reached 10.1 W at the maximum available pump power of 31 W. The combination of resonator design with diamond provides a novel approach to power-s...
Article
The external cavity CVD-diamond Raman laser generating at the wavelength of 1.63 µm was demonstrated for the first time. The laser was pumped by the Q-switched 1.34 µm Nd:YAP laser. Raman laser output energy of 47 µJ in the 6 ns long pulse with the fundamental spatial beam profile was obtained. (© 2012 by Astro Ltd., Published exclusively by WILEY-...
Conference Paper
Full-text available
We report an investigation into a 8.2 W diamond Raman laser with conversion efficiency of 27% pumped by a cw Nd:YVO4 laser. Power analysis enables determination of the factors limiting conversion efficiency.
Article
The goal of this work was the external cavity CVD diamond Raman laser generating at wavelength of 1.63 μm which belongs to an eye safe region. As the Raman medium a sample of CVD grown single diamond crystal was used. The crystal was grown in the [100] direction and after cutting, the sample sides were formed by {110} planes. The diamond crystal sa...