# Singapore 2011

Singapore 2011 is report on the trip to Singapore (2011 November 14-18 by Dmitrii Kouznetsov.

## Application of superfunctions in the Laser science

The 7th Laser Ceramics Symposium (7h LCS) is assisted with the oral presentation O-3 (2011 November 15, 11:45-12:05) entitled Transfer function of an amplifier and characterization of materials. The slideshow [1] is available in the PDF format. November 14, the registration of participants was delayed for two hours; that time was used for the improvised presentation and hard discussion of the superfunctions and the transfer functions of laser amplifiers (uniqueness of the superfunction, the range of applicability, possible extensions and generalizations, etc.). The participants are convinced with the main concept:
For any homogeneous distributed amplifier, characterized with transfer function $$T$$, the distribution of intensity inside is determined by the superfunction $$F$$ constructed by the regular iteration.
Then, at the official presentation, no more objections were formulated, only questions about the details of the formalism and the application.
The reprints of the articles about the transfer functions, superfunctions and the regular iteration are distributed. The article [2] with the application of the main result to the Laser Science is in preparation.

## Other presentations

Several presentations by other participants are discussed. In particular:

The use of the Yb-doped materials with low quantum defect by Mark Dubinski [3] is suggested for application to the Jerome Moloney group (University of Arizona, Arizona center for mathematical science). That presentation refers to the pumping at 1535nm and lasing at 1558nm; the volumetric Bragg reflectors are necessary to force the lasing at chosen wavelength. Such non-raditional pumping of the Yb–doped materials may be interesting also for the Institute for Laser Science, UEC.

The presentation by W.Streck [4] mostly looked as a retell of the first report about the Bisson-effect [5], but that article is not cited in the slideshow (and not mentioned in the talk). Such an event is qualified as scientific misconduct.

Prof. U.Wolters [6] is convinced that the Bisson effect may have thermal origin.

The presentations by V.B.Kravchenko [7] and the speech by A.Kaminskii [8] caused the philosophic discussion with Yurii Kopylov about the moral aspect of science. The topic touches the axioms of TORI; the short description of the Kopylov's point of view is written with his assistance and uploaded as Философия Копылова (in Russian).

Some of results presented by prof. Haojia Zhang [9] seem to be wrong. The medium with reported properties seems to be inconsistent with the Second Law of Thermodynamics. Such a problem had been reported and discussed previously [10][11][12]; the error in the measurements of the emission may be attributed to the methodologically–inconsistent protocol that does not take into account the reabsorption [13]. The discussion took place, the agreement is achieved: Prof. Haojia Zhang is convinced that the McCumber relation should hold for their materials.

Several presentations (I–4, I-6, I-9, I-13, O-14), were dedicated to the active mirrors (disk lasers). The discussions show that the general theoretical limit $$R^2/(Q \beta^3)$$ of the output power [14][15] and similar limit for the energy [16] for a disk lasers (expected to be experimentally over-jumped in 2009–2010) still holds.

The politics of non–distribution of pictures from the slideshows is discussed with prof.M.Mortier and prof.J.S.Sandhera. The agreement is not achieved; that time, the common point of view was not elaborated.

As the additional documents (in particular, some slideshows) become available online, the new links should be added. The comments and corrections are welcomed.

## Rerefences

1. http://tori.ils.uec.ac.jp/2011SINGAPO/76.pdf D.Kouznetsov. Transfer function of an amplifier and characterization of Materials. Singapore 2011 November 15, 11:45-12:05.
2. http://mizugadro.mydns.jp/PAPERS/2011recovery.pdf Dmitrii Kouznetsov. Recovery of intensity inside a uniform amplifier from its transfer function. Preprint ILS UEC, 2011.
3. http://www3.ntu.edu.sg/temasek-labs/lcs2011/Schedule.html Mark Dubinskii. “Er3+- and Ho3+- doped laser ceramics in resonantly-pumped eye-safe lasers”. 7th LCS, Presentaiton I-21, 2011 November 17, 15:50-16:20.
4. http://www3.ntu.edu.sg/temasek-labs/lcs2011/Schedule.html W.Strek, P.Gluchowski, L.Marciniak, D.Hreniak Broad band wight emission of Yb3+ doped nanoceramics. 7th LCS, Presentaiton I-21, 2011 November 17, 15:50-16:20.
5. http://mizugadro.mydns.jp/PAPERS/ApplPhysLett_90_201901.pdf J.-F.Bisson, D.Kouznetsov, K.Ueda, S.T.Fredrich-Thornton, K.Petermann, G.Huber. Switching of emissivity and photoconductivity in highly doped Yb3+:Y2O3 and Lu2O3 ceramics. Applied Physics Letters, v.90, 201901 (2007)
6. http://www3.ntu.edu.sg/temasek-labs/lcs2011/Schedule.html U.Wolters, S.T.Fredrich-Thornton1, J.Zhang, K.Petermann and G.Huber. “Photoconductivity in Yb:YAG Ceramics of Different Grain Size and Comparison with Single Crystalline Material”. 7h LCS, 2011 November 17, 16:20-16:50, presentation I-22.
7. http://www3.ntu.edu.sg/temasek-labs/lcs2011/Schedule.html S.N.Bagayev, A.A.Kaminskii, Yu.L.Kopylov , I.M.Kotelyanskii, V.B.Kravchenko, V.A.Luzanov. “Single Crystal Growth in YAG Ceramics of Different Stoichiometry”. 7th CLC, presentation O-4. 2011 November 17 12:05-12:25:
8. A.Kaminskii. Warning tendencies in the modern science. 7th LCS, 2011 November 17, out-of schedule talk.
9. http://www3.ntu.edu.sg/temasek-labs/lcs2011/Schedule.html Haojia Zhang, Qiuhong Yang, Shenzhou Lu, Dongdong huang, Yongang Wang. “Fabrication, Spectral and laser properties of 5 at% Yb3+doped (La0.10Y0.90)2O3 Transparent Ceramics”. 7h LSC, talk O-21, 2011 November 17, 11:45-12:05
10. http://www.ils.uec.ac.jp/~dima/PAPERS/perpetual.pdf Broadband laser materials and the McCumber relation. COE symposium P111,y.2006,Dec.2, UEC, Tokyo.
11. http://mizugadro.mydns.jp/PAPERS/ApplPhysLett_90_066101.pdf D.Kouznetsov. Efficient diode-pumped Yb:Gd2SiO5 laser: Comment. Applied Physics Letters, 90, 066101 (2007)
12. http://mizugadro.mydns.jp/PAPERS/2007mc.pdf D.Kouznetsov. Broadband laser materials and the McCumber relation. Chinese Optics Letters, 2007, v.5, p.S240-S242
13. http://apl.aip.org/resource/1/applab/v90/i6/p066103_s1 Guangjun Zhao, Liangbi Su, Jun Xu, and Heping Zeng. Response to “Comment on ‘Efficient diode-pumped Yb:Gd2SiO5 laser’” Appl.Phys.Lett. v.90, 066101 (2007).
14. http://mizugadro.mydns.jp/PAPERS/2009optmat.pdf D.Kouznetsov, J.-F.Bisson, K.Ueda. Scaling laws of disk lasers. Optical materials, v.31, Issue 5,2009, Pages 754-759.
15. http://mizugadro.mydns.jp/PAPERS/2007josacap.pdf D.Kouznetsov, J.-F.Bisson. Role of the undoped cap in the scaling of a thin disk laser. JOSA B, Vol.25, No.3, p.338-345 (2008).
16. http://mizugadro.mydns.jp/PAPERS/2008rlp717414.pdf D.Kouznetsov. Storage of energy in disk-shaped laser materials. Research Letters in Physics, v.2008 (2008), Article ID 717414.