Bibliometric Analysis of Research in the Field of Lasers
The lasers show a number of features of all-target high technologies. They have already been broadly applied in manufacturing industry, transport, power, health care, information and telecommunication technologies, scientific researches, ecology, military technologies. The Soviet and Russian scientists have made significant contribution to discovery of lasers, development of researches on their creation and use. It is worth to mention the Nobel Prize in physics in 1964 for development of operation principle of laser and maser, awarded to N. G. Basov and A. M. Prokhorov (jointly with American physicist C. H. Townes), the contribution of the Nobel laureate Z. I. Alferov and his school into creation of semiconductor lasers.
Owing to their mass character, journal publications have the greatest value in the analysis of scales, structure and sources of development of scientific area. Let us apply bibliometric approach to measure and evaluate quantity and influence of the publications about lasers made by the main participants of researches to reveal the structure of the international cooperation of the Russian scientists. The Science Citation Index Expanded database (SCIE DB), the most authoritative in the world the polythematic DB including more than 39 million scientific publications (articles, reviews, letters, etc.) in the reviewed journals, was chosen as a source of information.
Initial selection, about 290 thousand publications during 1980–2015, was received by search by key "LASER" terms (laser, nanolaser, light amplification by stimulated emission of radiation) in the names of publications. Its data have been used for macro analysis at the level of the countries. Information on 23162 publications with the address in Russia (in the USSR till 1992) has provided more detailed studying of contribution and scientific influence of domestic institutes and scientists. Services of Web of Knowledge platform allow us to receive traditional indicators (number of publications and quotes, average number of quotes per publication, etc.) for different subsets of initial selection. We use them, as well as some other rated indicators: annual average growth rate, share of publications with the international co-authorship, etc. In view of strong bias of distributions of cidetness, the indicators based on percentiles are more preferable for the analysis. The article considers top‑1% and top‑10% segments of the most highly cited publications in the area and the related indicators are used, for example: country share in elite part of world scientific literature, index of highly cited publications (IHCP) for the country or the organization, etc. When studying the participation of Russia in the specified segments, the attention was drawn to identification of highly high-quality researches, elite scientists and the institutes affiliating them, as well as checks of bibliometric criteria on belonging to the centers of scientific excellence (CSE). Separate results of earlier analysis of development of nano-researches will be used for the purposes of comparison .
This analysis is constructed from top to bottom: starting from cross-country comparison, through the level of the organizations and institutes, to the level of certain researchers.
Comparative analysis of Russia and other countries
More than 140 countries participated in researches in the field of lasers during the considered period; ten of the most productive countries are given in tabl. 1. Dynamics of publication activity of the five leading countries is shown in fig.1. Growth of China seems the most impressive which has passed over the USA in 2011, the previous leader. Other Asian country, Japan, is characterized by downward trend in 2000th due to which it has finally conceded the 3rd place on publication activity to moderately growing Germany. Up to 1992 the USSR was the second after the USA on the scale of researches in the field of lasers. In 2015 with 6.03-percentage share contribution to world publication output Russia took the 5th place. This contribution has exceeded the share publications of the Russian researchers by 2.5 times in total quantity of publications in WoS DB planned for 2015 in the Decree of the President of the Russian Federation . Thus, in terms of the number of the publications in the field of lasers Russia is among the leading countries which could not be achieved, for example, by intensive financing in nanoarea . Allocation and analysis of quickly growing directions is of interest. For example, ultrafast lasers which annual average growth rate of researches exceeded the indicator, general for the area, by 4 times in the 2000th. The publication contribution of Russia into this direction is by 2.6 percentage points (items) more than its general share contribution to study of lasers, and it is even more reliably in the group of leading countries (see Appendix).
The citedness in bibliometrics often serves as proxy indicator of scientific influence (or even quality of researches), and representation of the country in top‑1% and top‑10 the% segments of the most cited publications speaks about its entry into world elite in specific scientific area. The contribution of Russia (USSR) to the world top‑10% and top‑1% segments of publications about lasers for the entire period has made 3.4 and 3.5%, respectively. These values are much higher than similar indicators for nanoarea  that testifies to much bigger influence of the country in the field of research of lasers. Fig. 2 shows that by contribution into top‑10% segment of scientific literature, Russia was before China in 1980th and 1990th which, however, has considerably moved forward after 2003.
Since the raising wave of Chinese publications (the more articles are published, the more is the probability to be cited for this article) could affect it, dynamics of the indicator considering the scale of publishing output of the country is given in fig. 3. The index of highly cited publications  for top‑10 segment is defined by% as:
IHCPtop‑10% ≡ PPtop‑10% / 10,
where PPtop‑10% is the percent of highly cited publications in the general release of thematic publications of this country (observed value); 10 is the percent of such publications in universal output (expected value). By definition, if such ratio is more than 1, this country is better than "the world" as the producer of highly cited publications (in top‑10% segment), and vice versa. According to fig. 3, in 1990th and 2000th Russia and China were approximately equieffective producers of elite (top‑10%) publications in the field of lasers, approaching consistently to universal level. It should be noted that in terms of IHCP for top‑1% segment, Russia has exceeded China for long time, having conceded to it only in 2011. Also for comparison: PPtop‑1% for the Russian publications in the field of lasers for 2000–2009 (0.78%) has appeared above similar indicators for 22 wide subject domains of DB "Essential indicators of science". For example, the maximum value for physics was 0.68% .
The international cooperation (in bibliometrics referred as co-authorship) became important line of modern science. It means not only embedding into international production networks and exchange of scientific knowledge, but also the possibility to increase visibility of domestic researches  considerably. According to our calculations, the extent of internationalization of the Russian researches in the field of lasers has made about 32% in 1993–2015. During this period the country cooperated with more than 70 countries, closest with Germany (8.7% of joint publications), the USA (6.6%), France (4.6%), Japan (3.7%) and Great Britain (3.3%). Dynamics of cooperation of Russia with different groups of the countries is shown in fig. 4. As we see, cooperation with 4 leading Western countries in many respects defines the general trend for which rise by 25 pp by 2001, and then decrease (with two small "rebounds") by 10 pp is characteristic. The level of cooperation of Russia with the former Soviet republics and partners in BRICS remains rather low.
Among 256 Russian publications about lasers in 2010–2014 which have entered world top‑10% segment, 68.8% have the international co-authorship, generally with scientists from Great Britain, Germany, the USA, France and Japan. That is, the international co-authorship considerably increases probability for article to become highly cited, however, share of highly cited publications of the Russian authors alone (~ 31%) is more, for example, than similar share for nano-area (~ 15%) . Among the Russian publications since 1993 cited over hundred times, share of those written by the Russian authors alone is also quite high: ≈ 22%. This points to the degree of independence of the Russian researches and their demand for the world science.
Main Russian participants of researches
At meso-level, the Russian Academy of Sciences and higher education institutions are the main participants of researches in the field of lasers. Despite university-focused policy pursued by the Russian scientific authorities since 2006, the Russian Academy of Sciences remains dominating in these researches (tbl.2). The most productive scientists during 2012–2014 also represent the Russian Academy of Sciences: LPI RAS (5 employees), FORC RAS (1), JIHT RAS (2), IPTI RAS (2). Among the comparable world organizations, only the Chinese Academy of Sciences (CAS) advances the Russian Academy of Sciences on publication contribution, however, unlike nanotechnologies , the average gap in the number of quotes per publication between them is not so great: 6.3 against 5.3 in favor of CAN (for publications of 2012–2014). In the rating of world universities, MSU is on the 12th place, and is even slightly advances Qinghua University by average citedness.
Production of publications with higher influence can be even more important, than production of bigger number of publications therefore the contribution of the Russian participants to the elite part of scientific literature about lasers is of interest. It is provided by the community including about 450 domestic scientists during 2010–2014; the best of them according to bibliometric assessment are given in tbl. 3. It follows from tbl. 2 and 3 that the main contribution of the Russian scientists to elite part of scientific literature in the laser area is connected with fiber lasers, where IA&E of the Siberian Branch of the Russian Academy of Science plays leading role.
Let’s try to reveal (possible) CSE at the institutional level, having used the data from tbl. 4 and bibliometric criteria formulated in  for this purpose. First of all let us note that the academic scientific research institute and both universities have the required representation in the world scientific elite in the considered area : there is more than 5 publications in top‑10% and more than 2 publications in top‑1% segments (tabl. 3). The quoting of publications IA&E SB RAS significantly exceeds the average world level, than required 30%. Both indicators of IHCP for this institute also significantly exceed the criteria threshold 1.5 according to . Thus, in statistical terms IAE of the Siberian Branch of the Russian Academy of Science could be recognized as world class CSE in the field of lasers during 2010–2014. It should be also noted that it is coincides with expert assessment. The required criteria of CSE are also met by indicators of NSU, and only indicator of relative quoting does not reach criteria threshold for MEPhI. After consultation with experts for both universities additional bibliometric check has been executed which, in particular, has shown that: 1) approximately half of highly cited publications of NSU all authors with its affiliation are the regular employees of the institutes of the Siberian Branch of the Russian Academy of Science (mainly IA&E SB RAS) that calls into question the independence of contribution of the university is created under "system of Physics and Technology Faculty", as we know; 2) among publications with MEPhI affiliation, along with highly citedness, the share of low cited publications is considerable therefore this university, apparently, cannot be considered as the full applicant for CSE role in the field of lasers. MSU and IAP RAS, though are sufficiently represented in elite segments, do not satisfy other CSE criteria during the considered period.
It is worth mentioning, that expert and bibliometric methods of assessment of researches have both the advantages and disadvantages. Reasonable approach, in our opinion, is not in their opposition, but in flexible combination of advantages and cancellation of disadvantages of those methods. Bibliometric indicators make the examination more informed and transparent. Indicators, as well as their rated base, shall be improves constantly and, in order to avoid manipulations, aimed to be applied in a complex.
FINDINGS AND CONCLUSION
Lasers represent the area of global researches with more than sixty-year history. Having good start, Russia still holds decent world positions as confirmed by the carried-out bibliometric analysis. Unlike nanotechnologies adjusted by rush and large-scale financing, researches in the field of lasers develop on trajectory of moderate growth with annual average rate of 3.5% for the last seven years. For our country it is possible to note:
• smaller extent of internationalization of researches (32% of publications with the international co-authorship against 41% of such publications in nanotechnologies and 34% of all Russian publications in DB SCIE);
• smaller influence of university-focused policy of the government than in nanotechnologies (the Russian Academy of Sciences, still, remains the dominating participant of researches in the laser researches area, having kept the potential).
However such "conservatism" does not interfere with powerful competitive share of the Russian publications in world output (essentially exceeding 2.44% established by the presidential decree for all Russian publications) and high rates of scientific influence (close to indicators of China and considerably exceeding similar Russian indicators in nanoarea). In summary we will note that within this work, we could not estimate progress of military researches in the field of lasers for apparent reasons.
The following request was used for allocation of the publications relating to ultrafast lasers: TI = ("ultrashort pulse laser*" or "ultrafast laser*" or "picosecond laser*" or "femtosecond laser*" or "FS laser*" or "attosecond laser*" or "master oscillator power amplifier" or MOFA).
In total during 2000–2015, 8576 publications are selected, for Russia – 750. The rating of a number of leading countries in dynamics is presented in fig. 5. The Russian Academy of Sciences (75.7% of all Russian publications about ultrafast lasers) was the best in Russia in 2012–2014; with 6.6%, it was the second in the world after CAN (7.2%). Among non-university research institutes, LPI RAS concedes only to the State laboratory of laser physics of superstrong fields (CAN), meanwhile MSU is the first among world universities.
The work was supported by the Russian Foundation for Basic Research (grant No. 16–06–00009).