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ISP
computer network lab
Workshop on Industrial and medical applications of lasers (WIMAL-2000)
A Workshop on Industrial and Medical Applications of Lasers will be organized by ISP on February 27th and 28th, 2000. Experts from the fields of industry and medicine will deliver lectures on relevant topics. Over fifty participants from all over India will be taking part in the Workshop. The workshop is sponsored by UGC, Photonics Society and Indian Physics Association (Cochin Chapter).
We
hear that
CW atom laser
The world's first continuous atom laser has been produced at the University of Munich and the Max Planck Institute for Quantum Optics in Germany. All the previous atom laser beams- coherent beams in which all the atoms have the same wavelength and direction, just like the photons in a laser beam- have been pulsed. The Munich group created a Bose Condensate of Rb atoms in a magnetic trap and then punched a hole in the trap with a weak rf field (PRL 199,82, 3008).The atom laser lasted for 0.1 sec, its duration being limited by the number of atoms in the condensate. A quasi-continuous atom laser was demonstrated by researchers from Japan and US . They used the beam to perform Four Wave Mixing with matter waves for the first time.
Tabletop
laser fusion (TLF)
Physicists at Lawrence Livermore National laboratory (LLNL) ,California have demonstrated tabletop laser fusion for the first time. Todd Ditmire and colleagues used a TTL to irradiate clusters of deuterium atoms (Nature 398, 489, 1999) . The laser with peak intensity of 2.6X1016 watts cm-2 ionizes the D atoms and causes the cluster to explode. Pairs of D-ions then collide and fuse to form He3 and a neutron with 2.45 MeV. The Livermore team achieved an efficiency of about 105 fusion neutrons per joule of laser energy which approaches the efficiencies obtained in fusion energy experiments with more powerful lasers. However, the experiments are more relevant to the development of a tabletop neutron source for the study of materials than for research in the fusion energyIt is hoped that collaboration between ISP and the Dutch partner TUE will bear fruitful result in the near future and it will uplift the teaching and research activities of International School of Photonics to a truly international level.
Laser
induced fission and creation of antimatter
Cowan and co-workers of Livermore focused a Petta watt laser on to a gold coated uranium target causing ionisation of the atoms in the gold layer to form plasma. As the laser continued to interact with this plasma the Livermore team generated electrons of energies as high as 100MeV. The electrons collide with atoms in the target to generate high energy X-rays and gamma rays which in turn can knock neutrons out of gold nuclei and cause the fission of uranium nuclei. Besides various fission products like Sr, Ba, Y, Cs etc., the team also detected the presence of positrons which suggests that the high energy X-rays are creating electron - positron pairs in the target Phys. World 12, 5, 1999
Nonlinear
optics lends a hand to medical imaging
Radiation from femto-second pulsed visible laser (Ti:Sapphire) is frequency down-converted by a nonlinear optical crystal to terahertz or millimeter wave radiation which offers much safer, potentially more informative imaging in comparison to X-ray
image of teeth, skin and soft tissues. The Terahertz Pulse Imaging (TPI) can produce diagnostic informations which cannot be offered by imaging systems like X-rays, MRI or Ultrasound. TPI is safer than X-rays for medical imaging since Terahertz
waves are nonionising and the average power levels used are comparable to background levels encountered in everyday life. Moreover, with TPI, frequency can be varied over a wide range
from microwave (GHz) to mid IR (near 40 THz).
Some
of the recent publications from ISP
1.
Investigation of non linear absorption and aggregation in aqueous solution of RhB using thermal lens technique.
C V Bindhu , S S Harilal, V P N Nampoori and C P G Vallabhan. Pramana.52,435(1999).
2.
IPhotoacoustic study on photobleaching of Rhodamine 6G doped in poly methyl methacrylate
Nibu A George, Aneeshkumar B, P Radhakrishnan and C P G Vallabhan. J. Phys. D: Appl. Phys Vol. 32, (1999).
3.
Two and three photon absorption in Rh 6G methanol solution using pulsed thermal lens technique.
C V Bindhu, A Kurian, S S Harilal, V P N Nampoori and C P G Vallabhan. J.Nonlinear. Op. Phys. and Mat.7 (1999)
4.
Optical limiting and thermal lensing studies in C60. S S Harilal, C V Bindhu, V P N Nampoori and C P G Vallabhan. J.Appl.Phys.86,1388(1999)
9, No. 1, in
press)
5.
Solvent effect on absolute fluorescent quantum yield of Rhodamine 6G determined using transient thermal lens technique.
C V Bindhu, S S Harilal, V P N Nampoori and C P G Vallabhan. Mod. Phys. Lett. B 13, 563 (1999)
6.
Evaluation of electrical conductivity and thermal diffusivity of
VoNc. J Thomas, V N S Pillai, V P N Nampoori and C P G Vallabhan. J.Mat.Sci.Lett.18,963(1999).
7.
A fibre optic evanescent wave sensor for monitoring the rate of pulsed laser deposition of metal thin films.
M Shelly John, P Radhakrishnan, V P N Nampoori and C P G Vallabhan. Meas.
Sci. Technol.,10,17(1999).
8.
Thermal diffusivity of some polymer supported halogeno benzimidizole complexes of Co and Cu - a photoacoustic study.
S Sankara Raman, V P N Nampoori, C P G Vallabhan, N Saravanan and K K Mohammed Yusuff J. Mat. Sc. Lett. 18, 1887, (1999)
9.
Photoacoustic study of the effect of hydroxyl ion on thermal diffusivity of gamma alumina.
S Sankara Raman, V P N Nampoori, C P G Vallabhan, G Ambadas and S Sugunan. J.Appl. Phys. 85(3), 1987 (1999)
10.
Numerical study of reverse period doubling route from chaos to stability in a two-mode intra cavity doubled Nd:YAG laser.
Thomas Kuruvilla and V M Nandakumaran. CHAOS 9,208(1999)
11.
Suppression of chaos through reverse period doubling in coupled directly modulated semiconductor lasers.
Thomas Kuruvilla and V M Nandakumaran.Phys. Lett. A 254,59,(1999).
12.
Optical absorption studies of free and rare earth phthalocyanine doped borate glasses.
G A Kumar, J Thomas, N George, B A Kumar, P Radhakrishnan, V P N Nampoori, C P G
Vallabhan.
13.Physical and optical properties of phthalocyanine doped inorganic glasses.
G.A Kumar, J Thomas, N George, N V Unnikrishnan, P Radhakrishnan, V P N Nampoori, C P G Vallabhan. J. Mat. Sci., 35,1(2000)
Editor:
Dr. V P N Nampoori
Layout & graphics: Pravitha and Thomas Lee
Online version: B.Aneesh
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a hard copy
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