| 1. |
- Malmstrom, Mikael, et al.
(author)
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Waveguides in polycrystalline diamond for mid-IR sensing
- 2016
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In: Optical Materials Express. - 2159-3930 .- 2159-3930. ; 6:4, s. 1286-1295
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Journal article (peer-reviewed)abstract
- 8 mm long channel waveguides were manufactured in polycrystalline diamond with inductively coupled plasma etching and characterized in terms of mode-profile and propagation loss in the 1.5 - 3.4 mu m spectral region. As proof of principle, the waveguides were evaluated in an evanescent field sensing setup targeting the CH absorption peak of isopropanol at similar to 3.4 mu m, showing good agreement with numerical finite element simulations. (C) 2016 Optical Society of America
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| 2. |
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| 3. |
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| 4. |
- Mølster, Kjell Martin, 1992-, et al.
(author)
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THz time-domain reflection spectroscopy of KTiOPO4
- 2019
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Conference paper (peer-reviewed)abstract
- There is an ongoing development of THz sources for high-field applications, especially with the view of potential for THz-driven particle accelerators. For such sources nonlinear materials with high optical damage threshold and low loss are required. KTiOPO4, (KTP) is a well-established material for nonlinear optical applications in the visible and near-IR region thanks to its large transparency, high nonlinear coefficient and damage threshold. Its reasonably low absorption [1, 2] and strong coupling to phonon-polariton degree of freedom [1]. This shows promise for efficient IR to THz conversionprocess. Indeed,Wu et al.[2] recently demonstrated its superiority to LiNbO3and LiTaO3in a back to back experiment. In view of this, it is important to determinethe spectrum of complex refractive index over larger spectral range and with higher accuracy than has been do so far. KTP is an orthorhombic crystal belonging to mm2 point group with a rather complex vibrational mode structure containing 192 degrees of freedom. Earlier spectroscopic studies of KTP have either lacked the possibility of directly extracting the complex refractive index [3] or been limited by absorption of the transmitted signal due to the strong resonances of KTP, limiting the spectral extenttoabout 2.5 THz [4]. In this work we utilize reflection THz time-domain spectroscopy (TTDS) to determine the spectrum of the refractive index, n, and the absorption coefficient, , between 0.5 THz and up to 7 THz for two eigenpolarizations on the (001) plane.
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| 5. |
- Mølster, Kjell Martin, 1992-, et al.
(author)
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THz time-domain reflection spectroscopy of KTiOPO4
- 2019
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In: Optics InfoBase Conference Papers. - : OSA - The Optical Society. - 9781557528209
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Conference paper (peer-reviewed)abstract
- Terahertz (THz) radiation has been of increasing interest in the last decades, for security, manufacturing, quality control, medical and security imaging applications. The field requires more efficient and affordable sources and nonlinear upconversion schemes point in this direction. KTiOPO, (KTP) is a well-established material for nonlinear optical applications in the visible and near-IR region thanks to its large transparency, high nonlinear coefficient and damage threshold. Its reasonably low absorption [1, 2] and strong polariton resonances [1] show promise for efficient IR to THz upconversion and Wu et al. [2] recently demonstrated its superiority to LiNbO3 and LiTaO3 in a back to back experiment. However, the complex refractive index needs to be measured before further power scaling is realistic.
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| 6. |
- Mølster, Kjell Martin, 1992-, et al.
(author)
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Time-domain spectroscopy of KTiOPO4 in the frequency range 0.6–7.0 THz
- 2019
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In: OSA Continuum. - : Optical Society of America. - 2578-7519. ; 2:12, s. 3521-3538
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Journal article (peer-reviewed)abstract
- We report on THz time-domain spectroscopy measurements of flux grown KTiOPO4 in the frequency range 0.6–7.0 THz (20 to 240 cm−1). Our results compare well with earlier Raman and far-infrared measurements. We theorize that the differences between the optical phonon mode resonances reported in the literature are due to what growth parameters and melt compositions are used to grow the crystals. We also report on a new feature at 1.4 THz (47 cm−1).
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| 8. |
- Agate, B., et al.
(author)
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Portable ultrafast blue light sources
- 2004
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In: OSA Trends Opt. Photonics Series. - 1557527709 ; , s. 651-652
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Conference paper (peer-reviewed)abstract
- An effective means of achieving a portable, ultrafast blue-light source using a variety of nonlinear media is demonstrated. We investigate the relative merits of aperiodically-poled bulk and waveguide nonlinear crystals in comparison to periodically-poled structures.
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| 9. |
- Agate, B., et al.
(author)
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Portable ultrafast blue light sources designed with frequency doubling in KTP and KNbO3
- 2004
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In: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-260X .- 1558-4542. ; 10:6, s. 1268-1276
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Journal article (peer-reviewed)abstract
- We demonstrate an effective means of achieving compact, truly portable, and entirely self-contained ultrafast blue light sources. Using a variety of nonlinear media to achieve simple second-harmonic generation of a femtosecond Cr:LiSAF laser, we investigate the relative merits of aperiodically poled bulk and waveguide nonlinear crystals in comparison to periodically poled structures. Such a compact and convenient source of ultrashort laser pulses in the blue spectral region could be of great interest for on-site applications spanning a host of disciplines, such as biomedical imaging, optical micromanipulation, and high-resolution spectroscopy.
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| 10. |
- Arvidsson, G., et al.
(author)
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Anordning i form av koherent ljuskälla baserad på frekvenskonvertering av ljuset från lasrar : [Controllable laser light source uses two laser sources to enable frequency mixing such that three or four new wavelengths may be generated]
- 1990
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Patent (pop. science, debate, etc.)abstract
- The present invention concerns a coherent light source based on frequency conversion of the radiation from two lasers (20, 21) by frequency mixing in optical waveguides (10; 90), which are provided in a substrate (1). The wavelengths for the two lasers (20, 21) should be such, that the phase matching condition for the optically nonlinear frequency conversion is fulfilled in the waveguide structure (10; 90). The frequency conversion is accomplished in the form of frequency mixing, frequency doubling or down conversion in frequency by parametric oscillation so that in total three or four new wavelengths can be generated. By using integrated optics technique the output radiation can be controlled in various ways, for example be switched to different output waveguides, varied in intensity or colour balance.
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