Hamid Hemmati

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| The concept of deep-space optical communications was formulated shortly after the invention of lasers. The promise of laser communications, high data rate delivery with significantly reduced aperture size for the flight terminal, led to the pursuit of several successful experiments from Earth orbit and provided the incentive for further demonstrations to(More)
Several microwatts of tunable cw radiation near 194 nm in a linewidth of less than 2 MHz have been generated by sum-frequency mixing the radiation from a frequency-doubled argon-ion laser with the radiation from a ring dye laser in a crystal of potassium pentaborate. An external ring cavity resonant with the dye laser gives an enhancement factor of about 14(More)
We describe a method for the correction of slowly varying wavefront aberrations of low-quality telescope mirrors by using a DM in an active optical compensation system. Our goal is to reduce the surface wavefront error of low-cost multimeter-diameter mirrors from approximately 10 waves peak-to-valley (P-V), at a 1 microm wavelength, to approximately 1 wave(More)
Advanced Radio Interferometry Between Space and Earth (ARISE) is a space very long baseline interferometry (VLBI) mission with a nominal launch date of 2008. It consists of an inflatable 25-m radio telescope circulating in a highly elliptical Earth orbit with a perigee of 5,000 km and an apogee of 40,000 km. The objective is to observe in conjunction with(More)
Lutetium (III) texaphyrin photosensitizes postirradiation or "delayed" photohemolysis (DPH) of human and bovine red blood cells at 730 nm by a Type-2 pathway mediated by singlet molecular oxygen. The DPH rate increases with increasing incubation temperature and with the second power of the incident fluence. The experimental DPH curves are in good agreement(More)
  • Hamid Hemmati
  • 2014 16th International Conference on Transparent…
  • 2014
In response to an ever increasing demand for higher bandwidth, the free space optical (laser) communications technology has now matured to the point that is has commenced commercial use in Earth orbit at multi-Gb/s data-rates, and is on the verge of being demonstrated for the first time from other planets. This technology has long been used in terrestrial(More)
Lunar Laser Ranging studies the Moon’s internal structure and properties by tracking the variations in the orientation and tidal distortion of the Moon as a function of time. Future missions to the Moon’s surface should include new laser ranging instrumentation capable of improved range accuracy. A Planetary Science Decadal Survey White Paper: “Lunar(More)