| 1. |
- Coetzee, Riaan Stuart, 1987-, et al.
(författare)
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Gamma irradiation-induced absorption in single-domain and periodically-poled KTiOPO4 and Rb:KTiOPO4
- 2017
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Ingår i: Optical Materials Express. - 2159-3930 .- 2159-3930. ; 7:11, s. 4138-4146
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the effect of gamma radiation on flux grown KTiOPO4 and Rb:KTiOPO4 samples, as well as their periodically poled variants. Specifically, we study the altered transmission due to color-center formation via gamma irradiation. We measured the transmission of our samples for varying radiation doses and demonstrate effective temperature annealing of gamma radiation induced color centers. We measured a maximum transmission difference of 2% in our samples, which was easily corrected with temperature annealing. No long term and permanent changes were found to be induced in our samples.
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| 2. |
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| 3. |
- Dherbecourt, Jean Baptiste, et al.
(författare)
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Injection-Free and Cavity Free Parametric Sources for Future Spaceborne DIAL Based on Periodically Poled Nonlinear Materials
- 2024
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Ingår i: Springer Aerospace Technology. - : Springer Nature. ; , s. 363-371
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- We present new parametric source architectures for future spaceborne Differential Absorption Lidar (DIAL). This work focalizes on the developments performed during LEMON H2020 project using periodically poled nonlinear crystals. Such phase matching configuration offers the possibility to go towards more simple and robust set-ups for future space operation. We investigated injection-free optical parametric oscillator OPO set-ups, such as the Nested Cavity OPO–which allows a broad tuning range and thus can address several gas species with a single OPO—and also propose an injection and cavity free OPO solution using the counter-propagating phase matching configuration (Backward wave OPO). Moreover, we studied the implementation of high efficiency optical parametric amplifiers, to investigate the possibility to scale the output energies to several tens of mJ in the 2 µm region, and performed radiation testing on the specifically developed, large aperture, periodically poled KTP crystals.
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| 4. |
- Hamperl, Jonas, et al.
(författare)
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High Energy Parametric Laser Source and Frequency-Comb-Based Wavelength Reference for CO2 and Water Vapor DIAL in the 2 mu m Region : Design and Pre-Development Experimentations
- 2021
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Ingår i: Atmosphere. - : MDPI AG. - 2073-4433. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- We present a differential absorption lidar (DIAL) laser transmitter concept designed around a Nested Cavity Optical Parametric Oscillator (NesCOPO) based Master Oscillator Power Amplifier (MOPA). The spectral bands are located around 2051 nm for CO2 probing and 1982 nm for (H2O)-O-16 and (HDO)-O-16 water vapor isotopes. This laser is aimed at being integrated into an airborne lidar, intended to demonstrate future spaceborne instrument characteristics: high-energy (several tens of mJ nanosecond pulses) and high optical frequency stability (less than a few hundreds of kHz long term drift). For integration and efficiency purposes, the proposed design is oriented toward the use of state-of-the-art high aperture periodically poled nonlinear materials. This approach is supported by numerical calculations and preliminary experimental validations, showing that it is possible to achieve energies in the 40-50 mJ range, reaching the requirement levels for spaceborne Integrated Path Differential Absorption (IPDA) measurements. We also propose a frequency referencing technique based on beat note measurement of the laser signal with a self-stabilized optical frequency comb, which is expected to enable frequency measurement precisions better than a few 100 kHz over tens of seconds integration time, and will then be used to feed the cavity locking of the NesCOPO.
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| 5. |
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| 6. |
- Hamperl, Jonas, et al.
(författare)
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Range-resolved detection of boundary layer stable water vapor isotopologues using a ground-based 1.98 mu m differential absorption LIDAR
- 2022
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 30:26, s. 47199-47215
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a first demonstration of range-resolved differential absorption LIDAR (DIAL) measurements of the water vapor main isotopologue H216O and the less abundant semi-heavy water isotopologue HD16O with the aim of determining the isotopic ratio. The presented Water Vapor and Isotope Lidar (WaVIL) instrument is based on a parametric laser source emitting nanosecond pulses at 1.98 mu m and a direct-detection receiver utilizing a commercial InGaAs PIN photodiode. Vertical profiles of H216O and HD16O were acquired in the planetary boundary layer in the suburban Paris region up to a range of 1.5 km. For time averaging over 25 min, the achieved precision in the retrieved water vapor mixing ratio is 0.1 g kg-1 (2.5% relative error) at 0.4 km above ground level (a.g.l.) and 0.6 g kg-1 (20%) at 1 km a.g.l. for 150 m range bins along the LIDAR line of sight. For HD16O, weaker absorption has to be balanced with coarser vertical resolution (600 m range bins) in order to achieve similar relative precision. From the DIAL measurements of H216O and HD16O, the isotopic abundance delta D was estimated as -51%0 at 0.4 km above the ground and -119%0 in the upper part of the boundary layer at 1.3 km a.g.l. Random and systematic errors are discussed in the form of an error budget, which shows that further instrumental improvements are required on the challenging path towards DIAL-profiling of the isotopic abundance with range resolution and precision suitable for water cycle studies.
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| 7. |
- Melkonian, Jean-Michel, et al.
(författare)
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Long-wave infrared multi-wavelength optical source for standoff detection of chemical warfare agents
- 2020
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Ingår i: Applied Optics. - : Optical Society of America. - 1559-128X .- 2155-3165. ; 59:35, s. 11156-11166
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Tidskriftsartikel (refereegranskat)abstract
- We have designed and built a wavelength-tunable optical source for standoff detection of gaseous chemicals by differential absorption spectrometry in the long-wave infrared. It is based on a nanosecond 2 mu m single-frequency optical parametric oscillator, whose idler wave is amplified in large aperture Rb:PPKTP crystals. The signal and idler waves are mixed in ZnGeP2 crystals to produce single-frequency tunable radiation in the 7.5-10.5 mu n range. The source was integrated into a direct detection lidar to measure sarin and sulfur mustard inside a dosed chamber, in an integrated path configuration with a noncooperative target.
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| 8. |
- Mølster, Kjell Martin, 1992-, et al.
(författare)
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Highly efficient, high average power, narrowband, pump-tunable BWOPO
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We demonstrate a continuously tunable mid-infrared source that produces narrowband radiation at 1981 nm and 2145 nm based on a tunable Yb-based hybrid MOPA pump and backward-wave optical parametric oscillator (BWOPO). The BWOPO employs PPRKTP crystal with 580 nm domain periodicity. The BWOPO has a record-low oscillation threshold of 19.2 MW/cm2 and generates mJ-level output with efficiency exceeding 70%, reaching average power of 5.65W at the repetition rate of 5 KHz. The system is mechanically robust and optical cavity-free, making it suitable for spectroscopic systems on mobile platforms. The MIR signal frequency is tuned by pump tuning with a linear pump-to-signal frequency translation rate of 1-to-1.001 Hz/Hz. The tuning range of 10 GHz is demonstrated only limited by choice of the seed laser in the Yb-based MOPA system.
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| 9. |
- Mølster, Kjell Martin, 1992-, et al.
(författare)
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Highly efficient, high average power, narrowband, pump-tunable BWOPO
- 2023
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Ingår i: Optics Letters. - : Optica Publishing Group. - 0146-9592 .- 1539-4794. ; 48:24, s. 6484-6487
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a continuously tunable mid-infrared source that produces narrowband radiation at 1981 nm and 2145 nm based on a tunable Yb-based hybrid MOPA pump and a backward-wave optical parametric oscillator (BWOPO). The BWOPO employs a PPRKTP crystal with 580 nm domain periodicity. The BWOPO has a record-low oscillation threshold of 19.2 MW/cm2 and generates mJ level output with an overall efficiency exceeding 70%, reaching an average power of 5.65W at the repetition rate of 5 kHz. The system is mechanically robust and optical cavity-free, making it suitable for spectroscopic systems on mobile platforms. The mid-infrared signal frequency is tuned by pump tuning with a linear pump-to-signal frequency translation rate close to the predicted 1 to 1.001 Hz/Hz.
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| 10. |
- Mølster, Kjell Martin, 1992-, et al.
(författare)
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Low-threshold Highly Efficient Backward Wave OPO
- 2022
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Ingår i: Nonlinear Photonics, NP 2022. - : Optica Publishing Group (formerly OSA).
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Konferensbidrag (refereegranskat)abstract
- Cavity-free, precision-tunable source of a nanosecond, mJ-level, pulses consisting of backward optical parametric oscillator pumped by diode-seeded laser amplifier shows a record threshold of 19 MW/cm2 and an optical-to-optical efficiency exceeding 70%.
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| 11. |
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| 12. |
- Mølster, Kjell Martin, 1992-, et al.
(författare)
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Proton irradiation hardness of periodically poled Rb:KTP for spaceborne parametric frequency converters
- 2023
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Ingår i: Optical Materials Express. - : Optica Publishing Group. - 2159-3930 .- 2159-3930. ; 13:2, s. 436-446
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Tidskriftsartikel (refereegranskat)abstract
- Large aperture periodically-poled Rb:KTP crystals designed for optical parametric amplifiers in 2 µm LIDAR systems were radiation hardness tested by exposure of proton beams at 10 MeV and 60 MeV energies. An irradiation dose of 55 Gy was used to commensurate the crystals’ estimated exposure on board a mission in the low-Earth orbit. The irradiation effects were investigated by comparing optical transmission spectra and 2D effective nonlinearity mapping in a 2 µm OPO setup before and after irradiation. The results reveal that the periodically poled structure remained intact after irradiation, and the changes in the optical transmission and nonlinear properties were close to the measurement uncertainty. This investigation is essential for realizing efficient frequency converters for space applications, such as spaceborne active greenhouse gas monitoring LIDAR instruments or correlated photon-pair sources.
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| 13. |
- Mølster, Kjell Martin, 1992-, et al.
(författare)
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Proton radiation hardness of periodically poled Rb : KTiOPO4 for high-energy OPA at 2 mu m
- 2021
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Ingår i: Proceedings of the 2021 Conference On Lasers And Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Development of relevant technologies, for space-borne active instruments for measuring concentration distribution of greenhouse gases (GHG) in atmosphere, is increasingly important with the view of future missions supporting Earth observation programs, by all major space agencies [1] . Wavelength-agile differential absorption LIDARs employing tens of mJ pulse energies in the 2 µm spectral region have the capability of measuring concentrations of main GHG (CO 2 , CH 4 , H 2 O, HDO, N 2 O) throughout atmospheric column owing to well suited absorption lines. The required energy, efficiency and tunability of the LIDAR emitter can be readily obtained by employing high-energy optical parametric amplifier (OPA) based on large-aperture periodically poled Rb:KTP (PPKTP) [2] , seeded by the Nested Cavity Optical Parametric Oscillator (NesCOPO) [3] . Due to radiation environment in low-Earth orbit (LEO) the components, including nonlinear crystals need to be sufficiently radiation-resistant to sustain mission with typical duration of 5 years. We have recently verified that gamma radiation has minimal impact on PPKTP [4] .
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| 14. |
- Mølster, Kjell Martin, 1992-, et al.
(författare)
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Pump Tunable Mirrorless OPO : an Innovative Concept for Future Space IPDA Emitters
- 2023
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Ingår i: International Conference on Space Optics, ICSO 2022. - : SPIE-Intl Soc Optical Eng.
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Konferensbidrag (refereegranskat)abstract
- A highly efficient mirrorless OPO tunable in the mid-infrared around 2 μm has been developed and characterized in an original pumping configuration comprising a tunable high power hybrid Ytterbium laser MOPA (Master Oscillator Power Amplifier) in the nanosecond regime. The hybrid pump laser is based on a fiber laser seeder continuously tunable over several GHz at 1030 nm, which is shaped in the time domain with acousto-optic modulators (AOM), and power amplified in a dual stage Ytterbium doped fiber amplifiers, followed by two Yb:YAG bulk amplifiers. The pump delivers up to 3.5 mJ of energy within narrowband 15 ns pulses with a 5 kHz repetition rate. The output was focused into Periodically Poled KTP (PPKTP) crystals with a quasi-Phase Matching (QPM) period of 580 nm, producing Backward Optical Parametric Oscillation (BWOPO), with a forward signal wave at 1981 nm and a backward traveling idler at 2145 nm. We report significant optical to optical efficiencies exceeding 70 % depending on crystal length and input power. As theoretically expected, the forward wave could be continuously tuned over 10 GHz following the pump frequency sweep, while the backward wave remains almost stable, both being free from mode hops. These properties obtained from an optical arrangement without free-space cavities are attractive for future space Integrated Path Differential Absorption (IPDA) Lidar applications, which require robust and efficient tunable frequency converters in the mid-infrared.
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