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1

Metastability exchange optical pumping low field polarizer for lung magnetic resonance imaging

Collier G., Suchanek M., Wojna A., Cieslar K., Palasz T., Glowacz B., Olejniczak Z., Dohnalik T.

Optica Applicata

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2012

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Vol. 42, nr 1

223-239

EN

An extensive improvement of our low field polarizer is described. It produces 3He gas polarized up to 40% in a 6 h decay time storage cell. Production rate was raised by a factor of 10 to 4-5 scc/min thanks to the implementation of a new 10 W laser and a new design of a peristaltic compressor, easier to handle. Some applications of polarized gas are also presented: dynamic images of gas inhalation in the rat as well as a static image of human lungs using hyperpolarized gas were obtained.

2

Resonant cavity enhanced photonic devices.

Bugajski M., Muszalski J., Mroziewicz B., Regiński K., Ochalski T.J.

Optica Applicata

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2001

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Vol. 31, nr 2

273-288

EN

We review our recent works on technology, basic physics and applications of one-dimensional photonic structures. We demonstrate spontaneous emission control in In/sub x/Ga/sub 1-x/As/GaAs planar microcavities with DBR reflectors. The room temperature emission in lambda -sized cavities is enhanced in comparison with its free space value, while in lambda /2-sized cavities suppression of spontaneous emission is observed. The characteristics of spontaneous emission in microcavities depend on the wavelength difference between the emitter and the cavity resonance. It has been shown that ideal tuning of the cavity can be achieved by adjusting sample temperature. In general, observed trends are in agreement with theoretical predictions. These changes to the spontaneous emission process directly affect vertical-cavity laser (VCSEL) properties. An increased coupling efficiency of spontaneous emission into the lasing mode is observed in VCSELs with lambda -sized cavities. We demonstrate the operation of resonant-cavity light emitting diodes (RC LED) and optically pumped VCSELs developed recently at the Department of Physics and Technology of Low Dimensional Structures of the Institute of Electron Technology. The epitaxial growth issues, fabrication technology and basic characteristics of these devices are discussed

3

Laser diode pumping of an upconversion laser

Kaczmarek F.

Optica Applicata

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2001

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Vol. 31, nr 2

373-376

EN

Laser diode pumping in commonly applied in all solid state laser devices. In the case of an upconversion laser, i.e., when infrared-to-visible upconversion takes place in a rare-earth doped optical fiber, laser diode pumping is of special interest. Excitation of a single mode optical fiber, typically of core diameter of about 2 mu m, requires that the emitting area of the diode must be limited to 1 mu m *3 mu m, otherwise its emission cannot be focused to a spot of a few micrometers in size. As we have shown, short focal length lenses of high (NA approximately=0.4) ensure the best results. Numerical aperture (NA) matching is of less importance.

4

1.3 [my]m ND:YAG laser passively and actively Q-switched

Ostrowski R., Marczak J., Mierczyk Z.

Journal of Technical Physics

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2000

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Vol. 41, no 3

295-309

EN

The paper presents experimental results of investigation of flashlamp pumped Nd:YAG laser operated at, wavelengths lambda = 1.318 [my]m, lambda = 1.338 [my]m, lambda = 1.356 [my]m, lambda = 1.414 [my]m and lambda = 1.444 [my]m. Thresholds and resonator losses at these lines have been determined. The laser was also operated at line 1.318 [my]m in the Q-switched mode, both active and passive. In active Q-switching, output pulses up to 29 mJ energy and pulsewidth of 4l ns have been obtained. In passive Q-switching with V'3+:YAG crystalline saturable absorber, on the other hand, output pulses up to 4.5 mJ energy and 35 ns duration have been generated. Moreover, an intracavity Raman laser producing 1.53 [my]m radiation when pumped by Nd:YAG laser operated at 1.318 [mi]m is presented. Output Raman pulses up to 10 mJ energy have been obtained. Raman beam cleanup and 36% energy conversion efficiency have been observed.