Research Interests:

The Lasercomm experiment
The wireless international communication these days faces a practical bandwidth limitation since the frequency band offered by satellites is almost exhausted. In addition, the energy source of a satellite is limited, this results in the fact that broadening the frequency domain in a wireless system increases the cost of operation. Free-space optical communication, using the sun as its energy source, can contribute to overcome these problems.
A lab simulation for outer space solar laser communication was performed.
A combination of imaging and non-imaging concentrators for pumping solar laser and an amplifier were built and analyzed. An approximated 3D-CPC was designed, assembled and tested, using a ray-tracing program and a qualitative ray-tracing experiment. The laser crystal characteristics were measured under the system's pumping conditions. An oscillator-amplifier system was designed built and analyzed. Direct and indirect gain measurements were done. Gain up to 1.4 was measured at a low sun flux of 630 . Communication experiments were conducted using intensity modulation inside and outside the cavity.

The Power-Beaming Experiment
A simulation which demonstrates the power beaming concept, based on solar pumped laser and photovoltaic cell, was done. The simulation included a dish, a 3D CPC, a laser head for transmission and a cooled photovoltaic cell with homogenizer for converting the laser light into electricity.
Single Nd:YAG crystal was solar pumped using imaging and nonimaging systems producing 52 Watt laser at sun radiation of .
An experiment exposing the solar cell to a laser light was done using Nd:YAG and Alexandrite lasers. The results were 33% efficiency for the Nd:YAG laser and ~40% for the Alexandrite. Calculations that take into account the solar cell characteristics predict even higher efficiencies.
Other results of different experiments that were done in the past at the Weizmann Institute combined with the present study show that solar pumped lasers and photovoltaic cells can be successfully used in achieving the power beaming goal.

The Solar Pumped Dimmer Laser Experiment
The possibility of building lasers based on gas medium, with solar excitation was first discussed in 1976. Progress in the field of laser physics and technology, as well as the problems of energy resources on Earth and the need for ecologically clean energy sources, generated interest in the study of the possibility of direct conversion of solar radiation into laser radiation.
The use of dimmer vapor as the active media in solar pumped lasers holds a great deal of promise: they require lower pump power thresholds (because of the long energy level lifetimes and the narrow line-widths of the radiation) and they permit the use of large volumes of the active media, which is important in order to achieve high output power.
The general requirements of candidate gases for the active media of solar pumped lasers are: a) A broad (and a continuous as possible) absorption band in the region of the spectrum where the main part of the solar pumping radiation is concentrated; b) The existence of processes which, upon absorption of radiation produce a level population inversion. There is a large number of optically pumped dimmer vapor gases, pumped by laser line, but none of them was pumped using a non-monochromatic light source.

The Phase Conjugated Mirror Experiment

Recent Publications:

(Click the eye to download the full article)

I. Pe’er "High power, solar pumped, laser amplifier for free space laser communication" Thesis for the degree of Master of science, Weizmann Institute, Israel, 1996.

Idit Pe’er, Nir Naftali, Amnon Yogev "High power, solar pumped, Nd:YAG, laser amplifier for free space laser communication" , Proceedings of the SPIE - The international society for optical engineering, "Non-imaging Optics: Maximum Efficiency Light Transfer IV" vol.3139, p.194-204, 27-28 July 1997.

Nir Naftali, Idit Pe’er, Amnon Yogev "Power transmission using solar pumped laser", Proceedings of the SPIE - The international society for optical engineering, "Non-imaging Optics: Maximum Efficiency Light Transfer IV" vol.3139, p.259-265, 27-28 July 1997.

Nir Naftali "Power Transmission using solar pumped laser." Thesis for the degree of master in science, Weizman Institute of science, Israel, 1996.

Idit Pe’er, Nir Naftali, Dov Abramovic, Yoram Noter, Amnon Yogev "Passive Q-Switching of High Power Solar Pumped Nd:YAG Laser" Presented at GCL/HPL 96 held in Edinburgh, August 1996.

Yoram Noter, Nir Naftali, Idit Pe’er, Amnon Yogev "Performance of Passive Q-Switched , Solar Pumped, High Power Nd:YAG Lasers" The 10th meeting on optical Engineering in Israel, Vol.3110 Part One, P. 189-195 March 1997.

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