Solid-State Continuous-Wave Raman Lasers
Solid-State Continuous-Wave Raman Lasers
Tech Area / Field
- PHY-OPL/Optics and Lasers/Physics
- BIO-OTH/Other/Biotechnology and Life Sciences
- ENV-APC/Air Pollution and Control/Environment
3 Approved without Funding
B.I. Stepanov Institute of Physics, Belarus, Minsk
- Université de Paris VI / Université Pierre et Marie Curie / Laboratoire de Biophysique Moleculaire Cellulaire & Tissulaire, France, Evry\nUniversity of Pittsburg / School of Arts and Science, USA, PA, Pittsburgh\nPolish Academy of Science / Institute of Physics, Poland, Warsaw\nSincrotrone Trieste, Italy, Trieste\nWroclaw University of Technology / Institute of Biomedical Engineering and Instrumentation, Poland, Wroclaw\nUniversity of Toronto / University of Toronto at Mississauga, Canada, ON, Mississauga\nUniversity of Toronto / Institute for Optical Sciences, Canada, ON, Toronto\nTechnische Universität Berlin / Institute für Optik und Atomare Physik, Germany, Berlin\nFriedrich-Schiller-Universitat / Institut für Physikalische Chemie, Germany, Jena\nABDUS SALAM International Centre for Theoretical Physics, Italy, Trieste
Project summaryObjectives: The objectives of the Project are the investigation and development of new types of continuous wave (CW) solid-state lasers, in particular, lasers based on Raman-crystals. The lasers are intended for use in spectroscopy, life sciences, environment control, optical communications, and instrumentation. Their advantages over the existing CW lasers are as follows: generation of laser radiation at a lot of new spectral lines in the region of 270 nm to 1600 nm; low excitation threshold ( 0.5 W of laser diode power); output Stokes power of up to a few of watts; compactness (from 5 cm for diode-pumped intracavity Raman mini-lasers to about 15 cm for Raman lasers excited by CW coherent laser radiation); low cost.
Current State of the Art in the Research Area: CW laser sources are widely used in atomic and molecular spectroscopy, medicine, environmental control, optical communications and instrumentation. At the time being only a small number of CW lasers generating at a few fixed frequencies or wavelength-tunable in the limited visible and infrared spectral ranges are available. The nonlinear-optical methods, especially harmonic generation, sum-frequency mixing and optical parametric oscillation are used to extend the range of the wavelengths generated by CW laser sources.
One of the most well known nonlinear-optical effects is stimulated Raman scattering (SRS). SRS has been used for more than 40 years 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 to femtosecond pulses with pulse power of more than hundreds of kilowatts [N. Bloembergen. Rev. Mod. Physics. 71(1999)283; A.S.Grabtchikov, et al. Opt. Lett. 28(2003)926]. Such power level is needed mainly to fulfill the required Raman threshold conditions for typical Raman media. However, this power limitations lead to problems in achieving Raman conversion in the CW regime. The easily available CW laser systems can produce output powers of no more than a few tens of watts. As a result, the Raman conversion of CW laser radiation has been realized for only a limited number of special cases. These are resonant Raman scattering [G.D. Willenberg, et al. Opt. Commun. 33(1980)193], SRS in optical fibers [R.H. Stolen, et al. Appl. Phys. Lett. 20(1972)62], and oscillation in a Raman laser with a high-finesse cavity [J.K. Brasseur, et al. Opt. Lett. 23(1998)367]. Most of the above CW Raman lasers are rather complicated and expensive, which restricts the possibilities of their application in practice. Actually, only CW fiber Raman lasers have been used so far (primarily in optical communications).
The Project participants jointly with Prof. W.Kiefer (Germany), Prof. P.-Y.Turpin (France), Prof. H.Eichler (Germany), Prof. H.Szymczak (Poland) and Dr. M.Danailov (Italy) proposed in last three years a new approach to the creation of solid-state CW Raman lasers. These foreign scientists consented to be collaborators of the present Project or sent letters of support. In terms of the above approach the Project participants have realized for the first time:
- CW generation at the two Stokes spectral lines in a Raman laser on a Ba(NO3)2 crystal under excitation by the multimode radiation of an Argon-ion laser [A.S.Grabtchikov, et al. Opt. Lett. 29(2004)2524; V.A.Lisinetskii, et al. J. Raman Spectrosc. 37(2006)421; V.A.Orlovich et al. Conference Digest of the CLEO/Europe-IQEC 2007, 2007, CA-632].
- CW Raman generation in diode-pumped Nd:KGW and Nd:YVO4 mini-lasers. The Stokes radiation at 1181 and 1177 nm was generated as a result of the self-frequency conversion of laser radiation in Nd:KGW and Nd:YVO4 crystals placed in the cavity. [A.A.Demidovich, et al. Opt. Lett. 30(2005)1701; V.N.Burakevich, et al. Appl. Phys. B 86(2007)511].
- CW Raman generation in Ba(NO3)2, PbWO4 and KGW crystals placed inside the cavity of diode-pumped Nd:YVO4, Nd:LSB and Nd:YAG mini-lasers. [V.A.Orlovich, et al. Laser Phys. Lett. 3(2006)71; V.A.Orlovich et al. Conference Digest of the CLEO/Europe-IQEC 2007, 2007, CA-632]. By the method of intracavity second harmonic generation the CW radiation in the visible spectral region (590 nm) with the power of over 0.3 W has been obtained.
- CW Raman generation in a diode-pumped mini-laser based on composite Nd:KGW/KGW crystal. The quantum efficiency of laser diode radiation conversion into Stokes radiation was 22% [A.A. Demidovich, et al. Appl. Phys. B., 2007, in press]
Consistent elaboration of the above-mentioned preliminary results will allow the Project participants to achieve the formulated goal of the Project.
Project Effect on the Research Area Progress: As a result of the Project execution, a new type of solid-state CW lasers – CW crystalline Raman lasers, which have no analogs, will be developed. These CW Raman lasers will differ from the existing CW laser systems by their simplicity, cheapness, compactness, and new ranges of generated wavelengths that are important for various applications. The data to be obtained in the course of the Project will create a scientific and information basis for the development of different models of CW Raman lasers with the required output parameters and for the wide use of these lasers in practice.
Competence of Project Participants: The Project stuff consists of 38 researchers from the B.I.Stepanov Institute of Physics NAS Belarus including 2 professors, 9 candidates of science (Physics and Mathematics), and 27 researchers having higher education degrees and practical skills. All the above researchers are experts in laser physics, nonlinear optics, laser spectroscopy and laser engineering. Most of them have gained broad “weapons” experience in laser engineering. These researchers substantially contributed in the 1970s to 1990s to the laser physics and the study of the interaction of laser radiation with matter. In recent years, all the technical personnel of the Project have been working actively in the field of investigation and creation of lasers and nonlinear-optical systems of different types (first of all, Raman lasers and Raman converters) and their applications in spectroscopy, life sciences and instrumentation. [See, for example: Phys. Rev. A 56(1997)1666; Phys. Rev. Lett. 81(1998)5808; Opt. Lett. 28(2003)926, 29(2004)1415, 30(2005)1701; JOSA B 22(2005)453, 23(2006)1106; Opt. Commun. 218(2003)351, 244(2005)1, 260(2006)307, 263(2006)52; Appl. Phys. B 75(2002)795, 76(2003)509; Chem. Phys. Lett. 270(1997)293; Chem. Phys. 286(2003)97; J. Raman Spectrosc. 31(2006)339, 31(2006)851, etc.]. The technical personnel have also made much contribution to the experimental and theoretical substantiation of the present Project.
Expected Results and their Application: Following the fulfilling the four tasks of the Project, a number of new scientific and scientific-technical results will be obtained. The main of these results will be the following:
- Laws of origination and evolution of CW generation in crystalline Raman lasers pumped by the radiation of external lasers; the methods for developing high-stability low-threshold CW Raman lasers.
- Laws of intracavity Raman self-frequency conversion and Raman frequency conversion in CW diode-pumped mini-lasers; the methods and ways of obtaining low-threshold high-stability and high-efficiency generation in the near IR region, including eye-safe one, with an output power of a few watts.
- 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.
- A series of laboratory prototypes of CW Raman lasers for application in life sciences, environmental control and spectroscopy.
Thus, as a result of the Project execution, the problem of developing a new type of solid-state CW lasers will be completely solved. These lasers will have commercial value. Protection of the intellectual property in the Project and commercial manufacture of the developed products upon completion of the Project are planned.
Meeting ISTC Goals and Objectives:
- The project meets ISTC goals and objectives as:
- 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 above-mentioned peaceful activities.
- 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 supports basic and applied research and technology development exclusively for peaceful purposes.
- The project contributes to the solution of national and international technical problems; in particular, it promotes a wider use of CW solid-state lasers.
Realization of objectives of the project reinforces the transition of the project participants to market-based economies responsive to civil needs.
Scope of Activities: The Project duration will be 3 years. The total amount of effort will be 8215 person/days. Within the scope of the Project, it is planned to solve the following four interrelated tasks complementing each other:
- Study of the spectroscopic and nonlinear optical characteristics of a wide range of Raman crystals and the thermal effects induced in these crystals at Raman conversion.
- Study of the CW Raman lasers generation under pumping by the radiation of external lasers. Optimization of the output parameters of such Raman lasers for the generation at several spectral lines and the development of a CW Raman laser generating at two Stokes lines.
- Study of the intracavity Raman self-frequency and Raman frequency conversion in diode-pumped CW solid-state lasers and creation of the laboratory prototypes of such lasers.
- Creation of a specialized radiation source based on CW Raman lasers for use in spectroscopy, life sciences and environmental control; approbation of this source 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;
- carrying out part of the investigations jointly with EU collaborators on their facilities; joint use of textual materials and samples with collaborator from the EU, USA and Canada;
- participation in testing and using the devices developed in the course of the Project to carry out investigations in life sciences, medicine, chemistry and biology;
- participation in the technical monitoring of Project activities performed by ISTC staff;
- assistance to Project participants to joint international meetings;
- preparation of joint scientific papers, reports, and patents, establishing strategic proposals on the commercialization of the Project results.
Technical Approach and Methodology: The above stated results of preliminary investigations have shown that for the full-scale realization of the proposed Project it is necessary to make use of the approach based on a combination of theoretical and experimental methods of investigations. In general, theoretical calculations and computer simulation will be ahead of the experimental studies. In the experiments, up-to-date methods of laser physics and nonlinear optics will be used. The project participants have at their disposal experimental facilities and equipment needed for practical realization of these methods, which are supposed to be developed during the project. The laser and optoelectronic equipment, patents and technology developed earlier by the Project participants to orders of military enterprises and also as part of various national and international scientific Projects (including Project B-898 financed by ISTC) will be widely used at all stages of the Project.
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