Continuous Wave Laser with Intracavity Conversion
Continuous-Wave All-Solid-State End-Diode-Pumped Lasers with Intracavity Raman Conversion
Tech Area / Field
- PHY-OPL/Optics and Lasers/Physics
- ENV-APC/Air Pollution and Control/Environment
8 Project completed
Senior Project Manager
Malakhov Yu I
B.I. Stepanov Institute of Physics, Belarus, Minsk
- Technische Universität Berlin / Institute für Optik und Atomare Physik, Germany, Berlin\nSincrotrone Trieste, Italy, Trieste\nABDUS SALAM International Centre for Theoretical Physics, Italy, Trieste\nUniversité de Paris VI / Université Pierre et Marie Curie / Laboratoire de Biophysique Moleculaire Cellulaire & Tissulaire, France, Evry\nPolish Academy of Science / Institute of Physics, Poland, Warsaw
Project summaryObjectives: The objectives of the Project are the investigation and development of new types of continuous-wave (CW) all-solid-state laser systems, based on end-diode-pumped lasers with intracavity Raman conversion. The advantages of these laser systems over the existing CW lasers are as follows: generation of laser radiation at a lot of new spectral lines in the region of 280 nm to 1600 nm; output power of up to a few of Watts, compactness (length is less than 10 cm), low cost and low energy consumption (1 – 25 W). The laser systems are intended for use in life sciences, environment control, spectroscopy, chemistry, optical communications, and instrumentation.
Current State of the Art in the Research Area: Lasers generating CW radiation are widely used in molecular and atomic spectroscopy, medicine, environmental control, optical communications, etc. By now relatively small number of laser media allowing obtaining CW generation in the limited visible and infrared spectral ranges or at a few fixed frequencies are known. Therefore for obtaining CW radiation in other spectral regions the nonlinear optical methods are used, in particular optical parametric oscillation, frequency mixing, harmonic generation.
In recent years the effect of Stimulated Raman Scattering (SRS) is under investigation in many scientific centers. This effect is observed in gases, plasma, liquids, and solid-states media and widely used as a method for laser radiation frequency conversion to reach new spectral ranges. Raman conversion has been successfully applied in pulsed laser systems producing nanosecond [N.Bloembergen. Rev.Mod.Phys. 71(1999)283] to femtosecond [A.S.Grabtchikov, et. al. Opt. Lett. 28 (2003)926] pulses with pulse power of more than hundreds of kilowatts. This rather high level of laser radiation power which is necessary for SRS threshold exceeding leads to a lot of problems in achieving Raman conversion in the CW regime. By now the Raman conversion of CW laser radiation has been realized for only a limited number of special cases. These are SRS in optical fibers [R.H. Stolen, et al. Appl. Phys. Lett. 20(1972)62], in photonic crystal fiber filled with hydrogen [F.Benabid, et al. Science 298 (2002)399], and in silicon waveguide place in the cavity [H.Rong, et al. Nature. 433(2005)116]; resonant SRS [G.D. Willenberg, et al. Opt. Commun. 33 (1980) 193]; oscillation in Raman lasers on gases with a high-finesse cavity [J.K. Brasseur, et al. Opt. Lett. 23 (1998) 367]. At present only CW fiber Raman lasers are used in practice, primary in optical communications.
During the last three years the project participants jointly with Prof. W. Kiefer and Prof. H. Eichler (Germany), Prof. P.-Y. Turpin (France), Dr. M. Danailov (Italy) and Prof. H. Szymczak (Poland) proposed a new approach to the creation of all-solid-state CW Raman lasers. It is based on the use of intracavity Raman conversion in diode-pumped mini-lasers. As Raman medium some crystals are used. In terms of the above approach the project participants in collaboration with the above-mentioned European scientists have realized for the first time:
- CW Raman generation in end-diode-pumped Nd:YVO4 and Nd:KGW mini lasers. The Stokes radiation at 1177 nm and 1181 nm was generated as a result of the self-frequency Raman conversion of laser radiation in Nd:YVO4 and Nd:KGW crystals [A.A.Demidovich, et. al. Opt. Lett. 30 (2005) 1701; Burakevich V.N. et. al. Appl. Phys. B 86 (2007) 511].
- CW Raman generation in PbWO4, KGW and Ba(NO3)2 crystals placed in a cavity of end-diode-pumped Nd:LSB, Nd:YVO4 and Nd:YAG mini lasers [V.A.Orlovich, et. al. Laser Phys. Lett. 3 (2006) 71; P.A.Apanasevich et. al. Conference Digest of the CLEO/Europe-IQEC 2007, CA-632]. By the additional intracavity doubling of the Stokes radiation the CW radiation in the visible spectral range (590 nm) with the power of over 0,3 W has been obtained.
- CW Raman generation in the end-diode-pumped mini laser based on composite Nd:KGW/KGW crystal. The Raman threshold was 230 mW of laser diode power. The quantum efficiency of laser diode radiation conversion into Stokes radiation was 22 % [V.A.Lisinetskii, et. al. Appl. Phys. B 88 (2007) 499].
The result of the preliminary experiments stated above show the real possibility to reach the planed objectives of the project.
Project Effect on the Research Area Progress: As a result of project implementation the main features of intracavity Raman conversion of CW diode-pumped laser radiation will be established and new types of all-solid-state CW lasers, CW crystalline Raman lasers, will be created. These CW Raman lasers will differ from the existing CW lasers by new spectral ranges of generated wavelengths, cheapness, compactness and low energy consumption that are important for various applications. Extensive information concerning nonlinear optical properties of a large number of Raman crystals will be also accumulated. As a consequence a scientific, technical, and informational basis, necessary and sufficient for the development of different models of CW and pulsed Raman lasers with the required output parameters, will be created.
Competence of Project Participants: The staff of the project participants consists of 27 researchers and engineering workers from the B.I.Stepanov Institute of Physics NAS Belarus, including 3 professors, 7 candidates of sciences (Physics and Mathematics), and 17 researchers and engineers having higher educational degrees and practical skills. All the above researchers are the experts in nonlinear optics, laser physics and laser engineering, as well as in laser applications. Most of them have “weapons” experience in laser engineering. In recent years, all the project participants have been working actively in the field of investigation and creation of different types of lasers and nonlinear-optical systems (in particular, diode pumped lasers, Raman lasers, and Raman converters) and applications of laser light in spectroscopy, life sciences and environmental control [JOSA B 22 (2005) 453, 23 (2006)1106, 24 (2007) 2829; Opt. Lett. 28 (2003) 926, 29 (2004) 2524, 30 (2005) 1701; Phys. Rev. A 56 (1997) 1666; Phys. Rev. Lett. 81 (1998) 5808; Opt. Commun. 218 (2003) 351, 260 (2006) 307, 263 (2006) 52, 272 (2007) 509, 272 (2007) 467, 281 (2008) 2227; Appl. Phys. B 75 (2002) 795, 76 (2003) 509, 91 (2008) 299; J. Raman Spectrosc. 37 (2006) 421; Chem. Phys. 286 (2003) 97, etc.].
Expected Results and Their Applications:
Basic Research, Applied Research. As a result of fulfilling of four Project’s tasks a big number of new scientific and scientific-technical results will be obtained. The main of these results will be the following:
- Detailed information on the spectral and nonlinear-optical properties of a large number of Raman crystals; features of the influence of Raman crystal properties on the output parameters of CW Raman lasers; requirements to the crystalline Raman media for use in different types of CW Raman lasers.
- Law of the intracavity Raman self-frequency conversion in CW end-diode-pumped mini laser; the ways and methods of obtaining low-threshold high-stability and high-efficiency generation in the near IR region, including eye-safe spectral region, with an output power of up to a few watts; methods of high efficiency intracavity doubling and coherent mixing generated radiation to obtain CW radiation in the visible and UV spectral regions; the laboratory prototype of such laser.
- Law of intracavity Raman frequency conversion in CW end-diode-pumped mini laser; the ways and methods of obtaining low-threshold high-stability and high-efficiency generation with an output power of up to a few watts; the laboratory prototype of such laser.
- The laboratory prototype of specialized CW all-solid-state end-diode-pumped laser system and demonstration of its application in life sciences, environmental control and spectroscopy.
The results of performance of the Task 1-3 have a basic importance for laser physics and crystal optics, also they have an applicable importance for producers of a laser equipment and consumers of their products. The results of performance of the Task 4 have an applicable importance, because they demonstrate the possibilities of a practical using of the developed laser sources in different areas.
As a result of fulfillment of planned investigations the problem of the development of a new type of all-solid-state CW lasers will be completely solved. Protection of the intellectual property in the project and commercial manufacture of the developed laser systems upon completion of the project are planned.
Meeting ISTC Goals and Objectives:
The project meets ISTC goals and objectives as:
- The project supports basic and applied research and technology development exclusively for peaceful purposes, because the parameters of the developed laser sources can’t be used for military purposes.
- The project provides participants of the project, most of which possess knowledge and skills related to weapons of mass destruction, opportunities to redirect their talents, knowledge, and previous experience to peaceful activities connected with development of laser equipment for spectroscopy, life sciences, environment control, optical communication, and instrumentation.
- Realization of objectives of the project reinforces the transition of the project participants to market-based economies responsive to civil needs due to the creation of new working places for commercial production.
- The project promotes integration of its participants from Belarus into the international scientific community due to wide international scientific cooperation during project execution.
- The project contributes to the solution of national and international technical problems, in particular, it promotes a wider use of CW solid-state lasers.
Scope of Activities: The planned Project duration is three years. The total amount of efforts will be 6540 person/day. Within the scope of the project, it is planned to solve the following four interrelated tasks complementing each other:
- Experimental study of the nonlinear optical and spectroscopic characteristics of a wide range of Raman crystals and the thermal effects induced in these crystals at Raman conversion.
- Study of the intracavity Raman self-frequency conversion in end-diode-pumped CW all-solid-state lasers and creation of the laboratory prototype of such lasers.
- Study of the intracavity Raman frequency conversion in end-diode-pumped CW all-solid-state lasers and creation of the laboratory prototype of such lasers.
- Creation of specialized CW all-solid-state diode-pumped laser system for use in spectroscopy, life sciences and environmental control; approbation of this laser system in Raman spectroscopy of biological molecules, in medicine, chemistry, and biology.
Role of Foreign Collaborators: The following forms of cooperation with foreign collaborators are planned:
- systematic information exchange during the Project implementation;
- providing comments to the technical reports (quarterly, annual, final) submitted by Project participants to the ISTC;
- participation in some investigations and in testing and using the devices developed in the course of the Project to carry out investigations in life sciences, medicine, chemistry and biology;
- preparation of joint scientific papers, reports, and patents, establishing strategic proposals on the commercialization of the Project results;
- assistance to Project participants to joint international meetings;
- participation in the technical monitoring of Project activities performed by ISTC staff.
Technical Approach and Methodology: In the course of Project fulfillment it is planned to use the approach based on the comprehensive use of theoretical and experimental methods of the researches. In some cases (under fulfillment of the Tasks 2 and 3) theoretical investigations and numerical simulation will be ahead of the experimental studies. In the experiments up-to-date methods of nonlinear optics and laser physics will be used. The project participants have at their disposal experimental setups needed for realization of these methods. It is supposed that in the course of the project implementation new methods for measuring nonlinear-optical properties of Raman crystals will be developed. The laser, optical and electronic equipment, patents and technology developed earlier by the project participants to order of military enterprises and also as part of various national scientific projects will be widely used under investigations and creation of the laboratory prototypes of CW Raman lasers.
The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.
ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.