Query: Visible and mid-IR output using a fibre laser pump source

Candidate papers:

abstract: Results are presented for generation of visible and mid IR output using a common fibre based laser pump source. This source comprised a master oscillator power amplifier (MOPA) configuration incorporating a semiconductor seed source. Operation in the nanosecond and picosecond range is possible via use of the appropriate seed source. The MOPA is capable of generating 100 W average power in an output beam with an M2 of 1.1. Here the MOPA was operated in the nanosecond regime, using 100 ns seed pulses at a pulse repetition frequency of 100 kHz. 40 W each of pump power was available for a frequency doubling and an OPO stage. 9.8 W of green light was generated in an output beam with an M2 of 1.2; using a degenerate PPLN OPO 12.7 W of broadband mid IR output, with a FWHM linewidth in excess of 170 nm, was generated.
author_names: James Beedell

Ian F Elder

Kang Kang Chen

Shaif-ul Alam

David John Richardson

Duncan P Hand
title: Visible and mid IR output using a fibre laser pump source
venue: Security Defence
year: 2009

abstract: Mid infrared (mid IR) imaging and spectroscopic techniques have been rapidly evolving in recent years, primarily due to a multitude of applications within diverse fields such as biomedical imaging, chemical sensing, and food quality inspection. Mid IR upconversion detection is a promising tool for exploiting some of these applications. In this paper, various characteristics of mid IR upconversion imaging in the femtosecond regime are investigated using a 4f imaging setup. A fraction of the 100 fs, 80 MHz output from a Ti:sapphire laser is used to synchronously pump an optical parametric oscillator, generating 200 fs mid IR pulses tunable across the 2.7 4.0 mm wavelength range. The signal carrying mid IR pulses are detected by upconversion with the remaining fraction of the original pump beam inside a bulk LiNbO3 crystal, generating an upconverted field in the visible/near IR range, enabling silicon based CCD detection. Using the same pump source for generation and detection ensures temporal overlap of pulses inside the nonlinear crystal used for upconversion, thus resulting in high conversion efficiency even in a single pass configuration. A theory is developed to calculate relevant acceptance parameters, considering the large spectral bandwidths and the reduced interaction length due to group velocity mismatch, both associated with ultrashort pulses. Furthermore, the resolution of this ultrashort pulsed upconversion imaging system is described. It is demonstrated that the increase in acceptance bandwidth leads to increased blurring in the upconverted images. The presented theory is consistent with experimental observations.
author_names: Ashik A S

Callum Francis O'Donnell

S Chaitanya Kumar

Majid Ebrahim-Zadeh

Peter Tidemand-Lichtenberg

Christian Pedersen
title: Mid infrared upconversion imaging using femtosecond pulses
venue: Photonics Research
year: 2019

abstract: Fundamental properties of pure silica microstructured fibres (MSFs) can be determined by their geometrical crosssection design. Investigation of nonlinear effects was widely evaluated in diverse types of MSFs with exactly defined dispersive properties. Proper design of Zero Dispersion Wavelength (ZDW) strongly influences generation of nonlinear processes resulting especially in supercontinuum generation (SC) ZDW shift to short wavelengths together with high nonlinearity (small effective mode area) can be obtained by dramatic decrease of microstructured fibre pitch and increase of air filling ratio. Fibre geometry must be properly scaled preserving technological tolerances to obtain precisely defined position of ZDW near visible range. Additionally, higher air filling ratio results in multimode guiding regime. Therefore, in the paper we present studies of novel type of fibre geometry with ZDW near visible range together with endlessly single mode propagation regime. Chromatic dispersion measurements and ZDW analysis are performed with use of interferometric method. Presented MSFs series (the same structure type, but different ZDW position) is manufactured by stack and draw method. Proposed MSFs geometry enables fabrication of desired chromatic dispersion characteristic while respecting all technological tolerances, which is very difficult in case of manufacturing typical photonic crystal fibres for supercontinuum generated with 780 nm wavelength pulses from titanium sapphire laser. Additionally, proposed endlessly single mode operation provides high quality white light output beam, simultaneously with stable and flat SC source. Paper also reports on the SC generation with pumping in the anomalous and normal side of chromatic dispersion with femtoseconds and picoseconds pulses.
author_names: Zbyszek Holdynski

Marek Napierala

Urszula A Laudyn

Miroslaw A Karpierz

Michal Szymanski

Michal Murawski

Pawel Mergo

Pawel Marc

Leszek R Jaroszewicz

Tomasz Nasilowski
title: Analysis of supercontinuum generated with endlessly single mode new type of microstructured fibre series with near visible zero dispersion wavelength
venue: Photonics West Lasers and Applications in Science and Engineering
year: 2014

abstract: We propose a model for resonantly pumped Pr3+ doped chalcogenide fiber amplifiers which includes excited state absorption and the full spectral amplified spontaneous emission spanning from 2 mm to 6 mm. Based on this model, the observed nearand midinfrared photoluminescence generated from Pr3+ doped chalcogenide fiber is explained. Then the output properties of a 4.1 mm resonantly pumped Pr3+ doped chalcogenide fiber amplifier are simulated in both coand counter pumping schemes. Results show that the 4.1 mm counterpumped fiber amplifier can achieve a power conversion efficiency (PCE) of over 62.8 for signal wavelengths ranging from 4.5 mm to 5.3 mm. This is, to our best knowledge, the highest simulated PCE for a Pr3+ doped chalcogenide fiber amplifier. (c) 2018 Optical Society of America OCIS codes: (060.2360) Fiber optics amplifiers and oscillators; (140.3070) infrared and far infrared lasers; (160.5690) Rare earth doped material. References and links 1. B. Behzadi, M. Aliannezhadi, M. Hossein Zadeh, and R. K. Jain, "Design of a new family of narrow linewidth mid infrared lasers," J. Opt. Soc. Am. B 34(12) 2501 2513 (2017) 2. F. Kuhnemann, K. Schneider, A. Hecker, A. Martis, W. Urban, S. Schiller, and J. Mlynek, "Photoacoustic tracegas detection using a cw single frequency parametric oscillator," Appl. Phys. B 66(6) 741 745 (1998) 3. M. Van Herpen, S. Bisson, A. Ngai, and F. Harren, "Combined wide pump tuning and high power of a continuous wave, singly resonant optical parametric oscillator," Appl. Phys. B 78(3 4) 281 286 (2004) 4. M. S. Vitiello, G. Scalari, B. Williams, and P. De Natale, "Quantum cascade lasers: 20 years of challenges," Opt. Express 23(4) 5167 5182 (2015) 5. J. Li, U. Parchatka, and H. Fischer, "A formaldehyde trace gas sensor based on a thermoelectrically cooled CWDFB quantum cascade laser," Anal. Methods 6(15) 5483 5488 (2014) 6. Y. Yao, A. J. Hoffman, and C. F. Gmachl, "Mid infrared quantum cascade lasers," Nat. Photonics 6(7) 432 439 (2012) 7. V. V. Fedorov, S. B. Mirov, A. Gallian, D. V. Badikov, M. P. Frolov, Y. V. Korostelin, V. I. Kozlovsky, A. I. Landman, Y. P. Podmar'kov, and V. A. Akimov, "3.77 5.05 mm tunable solid state lasers based on Fe2+ doped ZnSe crystals operating at low and room temperatures," J. Quantum Electron. 42(9) 907 917 (2006) 8. S. B. Mirov, V. Fedorov, D. Martyshkin, I. Moskalev, M. Mirov, and V. Gapontsev, "Progress in mid IR Cr2+ and Fe2+ doped II VI materials and lasers," Opt. Mater. Express 1(5) 898 910 (2011) 9. M. Bernier, V. Fortin, N. Caron, M. El Amraoui, Y. Messaddeq, and R. Vallee, "Mid infrared chalcogenide glass Raman fiber laser," Opt. Lett. 38(2) 127 129 (2013) 10. M. Bernier, V. Fortin, M. El Amraoui, Y. Messaddeq, and R. Vallee, "3.77 mm fiber laser based on cascaded Raman gain in a chalcogenide glass fiber," Opt. Lett. 39(7) 2052 2055 (2014) 11. M. R. Majewski and S. D. Jackson, "Highly efficient mid infrared dysprosium fiber laser," Opt. Lett. 41(10) 2173 2176 (2016) 12. O. Henderson Sapir, S. D. Jackson, and D. J. Ottaway, "Versatile and widely tunable mid infrared erbium doped ZBLAN fiber laser," Opt. Lett. 41(7) 1676 1679 (2016) 13. O. Henderson Sapir, A. Malouf, N. Bawden, J. Munch, S. D. Jackson, and D. J. Ottaway, "Recent advances in 3.5 mm erbium doped mid infrared fiber lasers," J. Sel. Top. Quantum Electron. 23(3) 1 9 (2017) 14. V. Fortin, M. Bernier, S. T. Bah, and R. Vallee, "30 W fluoride glass all fiber laser at 2.94 mm," Opt. Lett. 40(12) 2882 2885 (2015) 15. F. Maes, V. Fortin, M. Bernier, and R. Vallee, "5.6 W monolithic fiber laser at 3.55 mm," Opt. Lett. 42(11) 20542057 (2017) 16. R. Woodward, M. Majewski, G. Bharathan, D. Hudson, A. Fuerbach, and S. Jackson, "Watt level dysprosium fiber laser at 3.15 mm with 73% slope efficiency," Opt. Lett. 43(7) 1471 1474 (2018) 17. R. M. Almeida and J. D. Mackenzie, "Vibrational spectra and structure of fluorozirconate glasses," J. Chem. Phys. 74(11) 5954 5961 (1981) 18. A. B. Seddon, Z. Tang, D. Furniss, S. Sujecki, and T. M. Benson, "Progress in rare earth doped mid infrared fiber lasers," Opt. Express 18(25) 26704 26719 (2010) 19. L. Shaw, B. Cole, P. Thielen, J. Sanghera, and I. Aggarwal, "Mid wave IR and long wave IR laser potential of rare earth doped chalcogenide glass fiber," J. Quantum Electron. 37(9) 1127 1137 (2001) 20. J. S. Sanghera, L. B. Shaw, and I. D. Aggarwal, "Chalcogenide glass fiber based mid IR sources and applications," J. Sel. Top. Quantum Electron. 15(1) 114 119 (2009) 21. L. Sojka, Z. Tang, D. Furniss, H. Sakr, A. Oladeji, E. Beres Pawlik, H. Dantanarayana, E. Faber, A. Seddon, and T. Benson, "Broadband, mid infrared emission from Pr3+ doped GeAsGaSe chalcogenide fiber, optically clad," Opt. Mater. 36(6) 1076 1082 (2014) 22. B. J. Park, H. S. Seo, J. T. Ahn, Y. G. Choi, D. Y. Jeon, and W. J. Chung, "Mid infrared (3.5 5.5 mm) spectroscopic properties of Pr3+ doped Ge Ga Sb Se glasses and optical fibers," J. Luminescence 128(10) 1617 1622 (2008) 23. I. D. Aggarwal and J. S. Sanghera, "Development and applications of chalcogenide glass optical fibers at NRL," J. Optoelectron. Adv. Mater. 4(3) 665 678 (2002) 24. M. C. Falconi, G. Palma, F. Starecki, V. Nazabal, J. Troles, J. L. Adam, S. Taccheo, M. Ferrari, and F. Prudenzano, "Dysprosium doped chalcogenide master oscillator power amplifier (MOPA) for mid IR emission," J. Lightwave Technol. 35(2) 265 273 (2017) 25. M. C. Falconi, G. Palma, F. Starecki, V. Nazabal, J. Troles, S. Taccheo, M. Ferrari, and F. Prudenzano, "Design of an efficient pumping scheme for Mid IR Dy3+ Ga5Ge20Sb10S65 PCF fiber laser," Photon. Technol. Lett. 28(18) 1984 1987 (2016) 26. Z. Tang, D. Furniss, M. Fay, H. Sakr, L. Sojka, N. Neate, N. Weston, S. Sujecki, T. M. Benson, and A. B. Seddon, "Mid infrared photoluminescence in small core fiber of praseodymium ion doped selenide based chalcogenide glass," Opt. Mater. Express 5(4) 870 886 (2015) 27. A. B. Seddon, D. Furniss, Z. Tang, T. Benson, R. Caspary, and S. Sujecki, "True mid infrared Pr3+ absorption cross section in a selenide chalcogenide host glass," in 18th International Conference on Transparent Optical Networks (ICTON) (IEEE, 2016) paper 7550709. 28. L. Sojka, Z. Tang, H. Zhu, E. Beres Pawlik, D. Furniss, A. Seddon, T. Benson, and S. Sujecki, "Study of midinfrared laser action in chalcogenide rare earth doped glass with Dy3+ Pr3+ and Tb3+" Opt. Mater. Express 2(11) 1632 1640 (2012) 29. J. Hu, C. R. Menyuk, C. Wei, L. B. Shaw, J. S. Sanghera, and I. D. Aggarwal, "Highly efficient cascaded amplification using Pr3+ doped mid infrared chalcogenide fiber amplifiers," Opt. Lett. 40(16) 3687 3690 (2015) 30. M. Khamis and K. Ennser, "Design of highly efficient Pr3+ doped chalcogenide fiber laser," Photon. Technol. Lett. 29(18) 1580 1583 (2017) 31. L. Sojka, Z. Tang, D. Furniss, H. Sakr, E. Beres Pawlik, A. Seddon, T. Benson, and S. Sujecki, "Numerical and experimental investigation of mid infrared laser action in resonantly pumped Pr3+ doped chalcogenide fibre," Opt. Quantum Electron. 49(1) s11082 016 0827 0 (2017) 32. P. Sourkova, B. Frumarova, M. Frumar, P. Nemec, M. Kincl, V. Nazabal, V. Moizan, J. L. Doualan, and R. Moncorge, "Spectroscopy of infrared transitions of Pr3+ ions in Ga Ge Sb Se glasses," J. Luminescence 129(10) 1148 1153 (2009) 33. R. Quimby, L. Shaw, J. Sanghera, and I. Aggarwal, "Modeling of cascade lasing in Dy: chalcogenide glass fiber laser with efficient output at 4.5 mm," Photon. Technol. Lett. 20(2) 123 125 (2008) 34. P. Becker, N. Olsson, and J. Simpson, Erbium Doped Fiber Amplifiers Fundamentals and Technology, (Academic 1999) Chap. 6. 35. A. A. Hardy and R. Oron, "Amplified spontaneous emission and Rayleigh backscattering in strongly pumped fiber amplifiers," J. Lightwave Technol. 16(10) 1865 1873 (1998) 36. E. Yahel and A. Hardy, "Modeling high power Er3+ Yb3+ codoped fiber lasers," J. Lightwave Technol. 21(9) 2044 2052 (2003) 37. E. Karaksina, V. Shiryaev, M. Churbanov, E. Anashkina, T. Kotereva, and G. Snopatin, "Core clad Pr(3+ doped Ga(In) Ge As Se (I) glass fibers: preparation, investigation, simulation of laser characteristics," Opt. Mater. 72, 654 660 (2017) 38. X. Zhu and R. Jain. "Numerical analysis and experimental results of high power Er/Pr: ZBLAN 2.7 mm fiber lasers with different pumping designs," Appl. Opt. 45(27) 7118 7125 (2006)
author_names: M T

B A
title: Shen, M. and Furniss, David and Tang, Z. and Barney, Emma R. and Sojka, L. and Sujecki, S. and Benson, Trevor M. and Seddon, Angela B. (2018) Modeling of resonantly pumped mid infrared Pr3+ doped chalcogenide fiber amplifier with different pumping
year: 2018

abstract: We report continuous wave powers up to 704 mW and quasi cw powers up to 1574 mW (50% duty cycle) at 588 nm from a diode pumped Nd:GdVO4 laser with intracavity Raman shifting (in KGd(WO4)2) and intracavity frequencydoubling (in LBO) with diode to 588 nm conversion efficiencies of up to 7% We also present a rate equation model of the laser which is used to outline the key design issues for cw intracavity doubled Raman lasers, in particular the roles played by thermal loading in the Nd:GdVO4 laser crystal, resonator mode sizes in the gain and nonlinear media and passive resonator losses. Introduction There is significant current interest in continuous wave (cw) solid state yellow laser sources for a diverse range of applications including ophthalmology, biomedicine and visual displays, and a variety of approaches have been taken to develop promising devices. These include an extra cavity, frequency doubled diode pumped Yb fibre laser generating 40 mW at 575 nm with a diode yellow conversion efficiency of 7% [1] a 3 W, 589 nm source based on extracavity frequency doubling of the 1179 nm output of a Raman fibre laser pumped by a diode pumped Yb fibre laser (estimated overall optical efficiency ~3% [2] and a 0.75 W, 593.5 nm laser source based on sum frequency mixing of the 1064 and 1342 nm lines of two Nd:YVO4 lasers with a diode yellow conversion efficiency ~11% [3] Our approach to developing yellow sources uses diode end pumped Nd lasers incorporating intracavity Raman shifting and second harmonicgeneration in crystalline materials; we believe this approach could yield practical, cost effective devices at low medium powers (up to ~1 W) due to the small number of components, small physical size, and the low complexity to assemble. Crystalline Raman lasers, based on a variety of Nd doped pump sources, have significantly increased the number of devices that can access the spectral region between 1.1 and 1.5 mm and also to the yellow orange spectral region through frequency doubling of the Stokes output (or by direct pumping the Raman material with frequency doubled Nd lasers [4] A wide variety of experimental configurations have been employed to achieve Raman conversion, including intracavity Raman generation, external resonator based lasers and Raman generators (primarily used with ultrashort pulse pump lasers) A recent review [5] provides an overview of the field. Prior to 2004, all reported crystalline Raman lasers had been pulsed devices, and it was believed that the high peak powers required to reach threshold for SRS necessitated a Q switched fundamental laser as the pump source for SRS. The first continuous wave (cw) crystalline Raman laser was reported by Grabitchikov, using an external Raman resonator pumped by an Ar laser at 514 nm [6] Three subsequent papers [7,8,9] reported cw Raman laser action using intracavity resonator configurations, and for the first time diode pumped laser systems. In this paper, we report a 704 mW cw intracavity frequency doubled Raman laser which operates in the yellow at 588 nm. To the best of our knowledge this is the first demonstration of an all solid state cw yellow laser based on crystalline media. We also outline the key design considerations required for efficient cw intracavity Raman laser action, and use numerical modelling to illustrate the interplay and trade offs between the various design parameters. Laser Design The Raman laser configuration is illustrated in Figure 1. The resonator was bounded by a pair of flat mirrors having high transmission at the diode (808 nm) and yellow (588 nm) wavelengths, and high reflectivity at fundamental (1063 nm) and Stokes (1176 nm) wavelengths. Two sets of mirrors were used in the experiments. Mirror set A, for operation at the first Stokes wavelength, and also for the yellow, had coatings with 85%T at 808 nm, 0.09%T at 1063 nm, 0.4%T at 1176 nm and 93%T at 588 nm) Mirror set B, used to obtain the highest yellow powers, had coatings with 96%T at 808 nm, 0.006%T at 1063 nm, 0.004%T at 1176 nm and 95%T at 588 nm) Resonator stability was achieved by way of the strong positive thermal lens in the laser gain medium (the thermal lens in the Nd:GdVO4 laser crystal for a incident pump power of 21 W had focal length estimated from measurements of resonator stability to be +66 mm) Cavity length was kept to a minimum, and was ~45 mm for operation at 1176 nm (no LBO in cavity) and ~62 mm for operation at 588 nm. Australian Institute of Physics 17th National Congress 2006 Brisbane, 3 8 December 2006 RiverPhys Paper No. WC016 2 The pump source was a 30 W fiber coupled 808 nm diode laser (ph=400 mm, NA 0.22) imaged with unity magnification onto an AR coated (1064 1200 nm) a cut 0.3at. Nd:GdVO4 crystal (3x3x10 mm) Raman shifting was obtained using a KGd(WO4)2 (KGW) crystal with dimensions of 5x5x25 mm, AR coated for the near infrared and cut and oriented for propagation along the Np axis with the plane of polarization parallel to Nn. KGW was selected for its superior thermal properties, good Raman gain coefficient and high damage threshold [10] Second harmonic generation (SHG) of the 1176 nm Stokes line was obtained using a temperature controlled ~45 degC) 3x3x10 mm non critically phase matched (NCPM, th=90deg, ph=0deg) LBO crystal coated AR at 1064 1200 nm. CW Laser Operation at 1176 nm (mirror set A) Threshold for lasing at the fundamental occurred for 0.7 W power from the laser diode, and we obtained Raman threshold for 6.6 W of incident pump power. Figure 2 shows the Stokes output as a function of pump power, together with the residual fundamental which becomes strongly depleted above threshold for SHG. Above threshold the 1176 nm firstStokes Raman power increased linearly with pump power, reaching 1563 mW from the output mirror for a maximum pump power of 20.4 W, limited by the onset of coating damage. Note also that the transmission of the input mirror was equal to that of the output mirror (0.4%T at 1176nm) thus approximately 1.5 W Raman power was lost from the input mirror. The low output coupler transmission at 1176 nm (0.4% in comparison with the other resonator losses (estimated to be at least 1% substantially limited the Raman laser output that could be obtained; clearly optimization of output coupling in relation to other losses would increase the output powers. CW Laser Operation at 588 nm (mirror set B) Nonlinear output coupling through frequency doubling of the Stokes optical field is particularly well suited to extracting the Stokes optical field efficiently. Low thresholds are possible due to the high Q cavity at both the fundamental and Stokes wavelengths) while at higher circulating fundamental and Stokes powers, losses are dominated by the nonlinear conversion to the visible, which is coupled from the resonator through a dichroic end mirror. The cw yellow output power at 588 nm as a function of diode pump power incident on the laser crystal in shown in Figure 3 (solid squares) At 15.5 W pump power the cw visible output was stable at 704 mW, with amplitude noise of approximately 12% At higher pump powers, the visible output decreased and became unstable as the resonator approached the stability limit. We note a similar yellow power would have been lost either through the input mirror or would have been absorbed in the Nd:GdVO4 laser crystal (a588nm>2cm 2 4 6 8 10 12 14 16 18 20 22 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 O ut pu t p ow er W Incident pump power W Residual 1063nm Raman 1176nm 2 4 6 8 10 12 14 16 18 20 22 24 26 0 200 400 600 80
author_names: Peter Dekker

Helen Pask

David J Spence

James A Piper
title: CONTINUOUS WAVE, ALL SOLID STATE, YELLOW LASER SOURCE AT 588 nm
year: 2006

abstract: Black Light or Wood's lamp refers to sources that emit long wavelength ultraviolet radiation (UV A) from 315 nm and little visible light till 410 nm (blue) In this paper, we present a new fibre based source of " black light " a source that emits broadband ultraviolet radiation but only small amounts of visible light and no infrared light. We made this source by pumping a specially designed silica photonic crystal fibre (PCF) with 355 nm light pulses from a Q switched frequency tripled Nd:YAG laser. Four wave mixing and cascaded Raman generation combine in the fibre to provide a supercontinuum output that spans from around 350 nm to 390 470 nm, with the exact spectral width dependent on the pump power, as shown in Fig. 1. This broadband black light source can find potential applications for diagnostic and therapeutic uses in medicine and in dermatology, for the detection of substances tagged with fluorescents and minerals, for counterfeit money, for absorption spectroscopy, and for military applications [1,2] Fig. 1. Output spectra for increasing input power from 0.5 to 4 mW showing black light continuum generation from 350 nm up to the blue at 470 nm in a 30 m long silica PCF pumped at 355 nm with 300 ps Q switched pulses. The inset shows the optical mode output.
author_names: Thibaut Sylvestre

M W Lee

A R Ragueh

Birgit Stiller

Gil Fanjoux

Benoit Barviau

Arnaud Mussot

Alexandre Kudlinski
title: Fiber based broadband black light source
year: 2012

abstract: We demonstrate a simple module for octave spanning continuous wave supercontinuum generation using standard telecom fiber. This module can accept any high power Ytterbium doped fiber laser as input. The input light is transferred into the anomalous dispersion region of the telecom fiber through a cascade of Raman shifts. A recently proposed Raman laser architecture with distributed feedback efficiently performs these Raman conversions. A spectrum spanning over 1000nm(>1 octave) from 880 1900nm is demonstrated. The average power from the supercontinuum is ~34W with a high conversion efficiency of 44% Input wavelength agility is demonstrated with similar supercontinua over a wide input wavelength range. References and links 1. Jinendra K. Ranka, Robert S. Windeler, and Andrew J. Stentz, "Visible continuum generation in air silica microstructure optical fibers with anomalous dispersion at 800 nm," Opt. Lett. 25, 25 27 (2000) 2. Dylan M. Owen, Egidijus Auksorius, Hugh B. Manning, Clifford B. Talbot, Pieter A. A. de Beule, Christopher Dunsby, Mark A. A. Neil, and Paul M. W. French, "Excitation resolved hyperspectral fluorescence lifetime imaging using a UV extended supercontinuum source," Opt. Lett. 32, 3408 3410 (2007) 3. Pei Lin Hsiung, Yu Chen, Tony H. Ko, James G. Fujimoto, Christiano J.S. de Matos, Sergei V. Popov, James R. Taylor, and Valentin P. Gapontsev, "Optical coherence tomography using a continuous wave, high power, Raman continuum light source," Opt. Express 12, 5287 5295 (2004) 4. T. Morioka, H. Takara, S. Kawanishi, O. Kamatani, K. Takiguchi, K. Uchiyama, M. Saruwatari, H. Takahashi, M. Yamada, T. Kanamori, and H. Ono, "1Tbit/s (100 Gbit/sx10 channel) OTDM/WDM transmission using a single supercontinuum WDM source," Electron. Lett. 32, 906 907 (1996) 5. J. M. Dudley, G. Genty, and S. Coen, "Supercontinuum generation in photonic crystal fiber," Rev. Mod. Phys. 78(4) 1135 1184 (2006) 6. B. A. Cumberland, J. C. Travers, S. V. Popov, and J. R. Taylor, "29 W High power CW supercontinuum source," Opt. Express 16, 5954 5962 (2008) 7. J. C. Travers, A. B. Rulkov, B. A. Cumberland, S. V. Popov, and J. R. Taylor, "Visible supercontinuum generation in photonic crystal fibers with a 400 W continuous wave fiber laser," Opt. Express 16, 14435 14447 (2008) 8. A. Kudlinski and A. Mussot, "Visible CW pumped supercontinuum," Opt. Lett. 33, 2407 2409 (2008) 9. A. K. Abeeluck, C. Headley, C. G. Jorgensen, "High power supercontinuum generation in highly nonlinear, dispersion shifted fibers by use of a continuous wave Raman fiber laser" Optics Letters 29, 18 (2004) 10. B. H. Chapman, S. V. Popov, R. Taylor, "Continuous Wave Supercontinuum Generation through Pumping in the Normal Dispersion Region for Spectral Flatness" IEEE Photonics Technology Letters 24, 15 (2012) 11. V. Choudhury, S. Arun, R. Prakash and V. R. Supradeepa, "High power, equalized, continuous wave supercontinuum generation using cascaded Raman fiber amplifiers," 2017 Conference on Lasers and ElectroOptics Europe European Quantum Electronics Conference (CLEO/Europe EQEC) 2017, pp. 1 1. 12. Thibaut Sylvestre, Armand Vedadi, Herve Maillotte, Frederique Vanholsbeeck, and Stephane Coen, "Supercontinuum generation using continuous wave multiwavelength pumping and dispersion management," Opt. Lett. 31, 2036 2038 (2006) 13. G. P. Agrawal, Nonlinear Fiber Optics (Academic, 2007) 14. V. R. Supradeepa, Y. Feng and J. W. Nicholson, "Raman fiber lasers," J. Opt. 19, 023001 (2017) 15. S. A. Babin, I. D. Vatnik, A. Yu. Laptev, M. M. Bubnov, and E. M. Dianov, "High efficiency cascaded Raman fiber laser with random distributed feedback," Opt. Express 22, 24929 24934 (2014) 16. Lei Zhang, Huawei Jiang, Xuezong Yang, Weiwei Pan, and Yan Feng, "Ultra wide wavelength tuning of a cascaded Raman random fiber laser," Opt. Lett. 41, 215 218 (2016) 17. S. Arun, V. Balaswamy, S. Aparanji and V. R. Supradeepa, "High power, grating free, cascaded Raman fiber lasers," 2017 Conference on Lasers and Electro Optics Europe European Quantum Electronics Conference (CLEO/Europe EQEC) 2017, pp. 1 1. 18. V. Balaswamy, S. Arun, Santosh Aparanji, Vishal Choudhury and V. R. Supradeepa, "High Power, Fixed and Tunable Wavelength, Grating Free Cascaded Raman Fiber Lasers," arXiv:1711.10966 [physics.optics] (2017) 19. S. K. Turitsyn, S. A. Babin, A. E. El Taher, P. Harper, D. V. Churkin, S. I. Kablukov, J. D. Ania Castanon, V. Karalekas, and E. V. Podivilov, "Random distributed feedback fibre laser," Nat. Photonics 4, 231 235 (2010) 20. J. W. Nicholson, M. F. Yan, P. Wisk, J. Fleming, F. DiMarcello, E. Monberg, T. Taunay, C. Headley, and D. J. DiGiovanni, "Raman fiber laser with 81 W output power at 1480 nm," Opt. Lett. 35(18) 3069 3071 (2010) 21. Skryabin, D. V. and A. V. Yulin, "Theory of generation of new frequencies by mixing of solitons and dispersive waves in optical fibers," Phys. Rev. E 72, 016619 (2005) 22. V. Balaswamy, S. Aparanji, G. Chayran, and V. R. Supradeepa, "Tunable Wavelength, Tunable Linewidth, High Power Ytterbium Doped Fiber Laser," in 13th International Conference on Fiber Optics and Photonics, OSA Technical Digest (online) (Optical Society of America 2016) paper Tu3E.4. (2016)
author_names: A S

B V

R V
title: High power, high efficiency, continuous wave supercontinuum generation using standard telecom fibers
year: 2018

abstract: We have developed a fibre based source of "black light" a source that emits broadband ultraviolet radiation but only small amounts of visible light and no infrared light. We made this source by pumping a specially designed silica photonic crystal fibre with 355 nm light pulses from a Q switched frequency tripled Nd:YAG laser. Four wave mixing and cascaded Raman generation combine in the fibre to provide a broadband continuum output that spans from around 350 nm to 390 470 nm, with the exact spectral width dependent on the pump power. We discuss the main limitations in terms of bandwidth and power due to temporal walk off, fiber attenuation and solarization and we suggest simple solutions for further progress. This broadband black light source could be useful for performing gas absorption spectroscopy or exciting various fluorescent proteins used in biological studies.
author_names: Thibaut Sylvestre

A R Ragueh

M W Lee

Birgit Stiller

Gil Fanjoux

Benoit Barviau

Arnaud Mussot

Alexandre Kudlinski
title: Supercontinuum generation in the black light region by pumping at 355 nm a silica photonic crystal fiber
venue: Photonics Europe
year: 2012

abstract: El proceso de soldadura por laser desarrollado en los ultimos anos ha puesto de manifiesto las posibilidades de aplicacion de esta tecnologia en diferentes sectores productivos, principalmente en la industria automovilistica, en la cual se han demostrado sus ventajas en terminos de productividad, eficiencia y calidad. El uso de la tecnologia laser, ya sea hibrida o pura, reduce el input termico al limitar la zona afectada por el calor, sin crear deformaciones y, por tanto, disminuye los re trabajos post soldadura necesarios para eliminarlas. Asimismo, se aumenta la velocidad de soldadura, incrementando la productividad y calidad de las uniones. En la ultima decada, el uso de laseres hibridos, (laser arco) de gran potencia de Neodimio YAG, (Nd: YAG) ha sido cada vez mas importante. La instalacion de este tipo de fuentes de laser solido de gran potencia ha sido posible en construccion naval debido a sus ventajas con respecto a las instalaciones de laser de C02 existentes en los astilleros que actualmente utilizan esta tecnologia. Los laseres de C02 estan caracterizados por su gran potencia y la transmision del haz a traves de espejos. En el caso de las fuentes de Nd:YAG, debido a la longitud de onda a la cual se genera el haz laser, su transmision pueden ser realizada a traves de fibra optica haciendo posible la utilizacion del cabezal laser a gran distancia de la fuente, aparte de la alternativa de integrar el cabezal en unidades robotizadas. El proceso laser distribuye el calor aportado de manera uniforme. Las caracteristicas mecanicas de dichas uniones ponen de manifiesto la adecuacion de la soldadura por laser para su uso en construccion naval, cumpliendo los requerimientos exigidos por las Sociedades de Clasificacion. La eficiencia energetica de los laseres de C02, con porcentajes superiores al 20% aparte de las ya estudiadas tecnicas de su instalacion constituyen las razones por las cuales este tipo de laser es el mas usado en el ambito industrial. El laser de gran potencia de Nd: YAG esta presente en el mercado desde hace poco tiempo, y por tanto, su precio es relativamente mayor que el de C02, siendo sus costes de mantenimiento, tanto de lamparas como de diodos necesarios para el bombeo del solido, igualmente mayores que en el caso del C02. En cambio, el efecto de absorcion de parte de la energia en el plasma generado durante el proceso no se produce en el caso del laser de Nd: YAG, utilizando parte de esa energia en estabilizar el arco, siendo necesaria menos potencia de la fuente, reduciendo el coste de la inversion. En funcion de la aplicacion industrial, se debera realizar el analisis de viabilidad economica correspondiente. Dependiendo de la potencia de la fuente y del tipo de laser utilizado, y por tanto de la longitud de onda a la que se propaga la radiacion electromagnetica, pueden existen riesgos para la salud. El laser de neodimio se propaga en una longitud de onda, relativamente cercana al rango visible, en la cual se pueden producir danos en los ojos de los operadores. Se deberan establecer las medidas preventivas para evitar los riesgos a los que estan expuestos dichos operadores en la utilizacion de este tipo de energia. La utilizacion del laser de neodimio: YAG ofrece posibilidades de utilizacion en construccion naval economicamente rentables, debido su productividad y las buenas caracteristicas mecanicas de las uniones. Abstract The laser welding process development of the last years shows broad application possibilities in many sectors of industry, mostly in automobile production. The advantages of the laser beam process produce higher productivity, increasing the quality and thermal efficiency. Laser technology, arc hybrid or pure laser welding, reduces thermal input and thus a smaller heat affected zone at the work piece. This means less weldment distortion which reduces the amount of subsequent post weld straightening work that needs to be done. A higher welding speed is achieved by use of the arc and the laser beam, increasing productivity and quality of the joining process. In the last decade use of hybrid technology (laser GMA hybrid method) with high power sources Nd:YAG lasers, gained in importance. The installation of this type of higher power solid state laser is possible in shipbuilding industrial applications due to its advantages compare with the C02 laser sources installed in the shipyards which use this technology. C02 lasers are characterised by high power output and its beam guidance is via inelastic system of mirrors. In the case of Nd:YAG laser, due to its wavelength, the laser beam can be led by means of a flexible optical fibre even across large distances, which allows three dimensional welding jobs by using of robots. Laser beam welding is a process during which the heat is transferred to the welded material uniformly and the features of the process fulfilled the requirements by Classification Societies. So that, its application to the shipbuilding industry should be possible. The high quantum efficiency of C02 laser, which enabled efficiency factors up to 20% and relative simple technical possibilities of implementation are the reasons for the fact that it is the most important laser in industrial material machining. High power Nd: YAG laser is established on the market since short time, so that its price is relatively high compared with the C02 laser source and its maintenance cost, lamp or diode pumped solid state laser, is also higher than in the case of C02 lasers. Nevertheless effect of plasma shielding does not exist with Nd:YAG lasers, so that for the gas shielding welding process the optimal gases can be used regarding arc stability, thus power source are saved and the costs can be optimised. Each industrial application carried out needs its cost efficiency analysis. Depending on the power output and laser type, the dangerousness of reflected irradiation, which even in some meters distance, affects for the healthy operators. For the YAG laser process safety arrangements must be set up in order to avoid the laser radiation being absorbed by the human eye. Due to its wavelength of radiation, being relatively close to the visible range, severe damage to the retina of the eye is possible if sufficient precautions are not taken. Safety aspects are of vital importance to be able to shield the operator as well as other personal. The use of Nd:YAG lasers offers interesting and economically attractive applications in shipbuilding industry. Higher joining rates are possible, and very good mechanical/technological parameters can be achieved.
author_names: A Abecia
title: Analisis de la aplicacion de Soldadura de acero de calidad "A"mediante laser de Neodimio YAG en construccion naval
year: 2013

abstract: We characterize a cw OPO featuring narrow linewidth and the possibility of phase locking to optical frequency standards. We present a novel scheme for transferring frequency stability between the IR and visible. The mid IR spectral range around 3 mm is of great interest to high resolution spectroscopy and metrology since it contains fundamental vibrational modes of molecular bonds including hydrogen. Accessing these transitions provides vast opportunities for fundamental research and industrial applications. Their spectroscopic investigation, however, is hindered by the lack of appropriate tunable laser sources operating in this spectral region. Continuous wave optical parametric oscillators (cw OPOs) are one of the few viable options. We present a practical cw OPO device that offers several advantages over analogous systems. Its detailed description and the first application for Doppler free spectroscopy of methane are reported in [1] The singly resonant OPO with resonated pump is based on a periodically poled lithium niobate (PPLN) crystal pumped by a monolithic Nd YAG laser. The OPO contains a specially designed intracavity etalon, which allows controlled access to any desired frequency in a wide emission range: 1.5 1.9 mm (signal) and 2.4 3.7 mm (idler) The output radiation has a linewidth less than 15 kHz and power levels of 10 50 mW. We have shown that the OPO output frequencies can be easily phase locked to independent laser sources in the visible and IR ranges. These features of the OPO combined with the recently developed optical frequency combs based on femtosecond mode locked lasers [2] open up a series of new opportunities in optical metrology. We propose a scheme that allows to phase lock the OPO output frequencies and a femtosecond laser frequency comb to each other. Our idea is based on the fact that our OPO emits not only the signal (S) and idler (I) waves (with pump frequency P=S+I) but also a variety of (not necessarily phase matched) linear combinations of the two frequencies. Some of these frequencies (P+S, P+I, 2S) are located in the emission range of a mode locked femtosecond Ti:Sapphire laser and can be used for the mutual frequency stabilization of the two sources. In this arrangement the OPO serves as a bridge that transfers the stability of frequency standards operating in the nearand mid IR into the visible and vice versa. This paves the way for developing a precise frequency synthesizer for the entire optical range. One can also use the OPO frequency comb tandem to compare frequency standards of different physical nature and thus carry out fundamental tests of physics.
author_names: Evgeny V Kovalchuk

A I Lvovsky
title: Spectral Properties and Frequency Control of Optical Parametric Oscillators for Applications in Metrology
year: 2002