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We report on the design and performance of the laser deployed in the airborne demonstrator Doppler wind lidar for the Aeolus mission of the European Space Agency (ESA). The all-solid-state, diode-pumped and frequency-tripled Nd:YAG laser is realized as a master oscillator power amplifier (MOPA) system, generating 60 mJ of single-frequency pulses at 355 nm wavelength, 50 Hz repetition rate and 20 ns pulse duration. For the measurement of the Doppler frequency shift over several accumulated laser shots, the frequency stability of the laser is of crucial importance. Injection-seeding, in combination with an active cavity control based on the Ramp-Delay-Fire technique, provides a pulse-to-pulse frequency stability of 0.25 MHz measured at 1064 nm under laboratory conditions. This value increases to 0.31 MHz for airborne operation in a vibration environment that has been characterized by multiple acceleration sensors during different flight conditions. In addition, a pure Ramp-Fire setting was tested for comparison leading to a frequency stability of 0.16 MHz both in airborne operation and on ground. The laser cavity control electronics also have to provide a trigger signal for the lidar detection electronics, about 60 μs prior to the expected laser pulse emission and with high timing stability. An in-flight timing stability of below 100 ns was measured decreasing to 20 ns for a shorter pre-trigger time of 10 μs.
This article was published in the following journal.
Name: Applied optics
We report on a frequency stabilized laser system with a variable linewidth at a wavelength of 404.7 nm used as an incoherent repump on the 6P30↔7S31 transition in mercury. By directly modulating the...
We have developed a Watt-level single-frequency tunable fiber laser in the 915-937 nm spectral window. The laser is based on a neodymium-doped fiber master oscillator power amplifier architecture, wi...
A simple digital control system was designed to stabilize CO2 laser based on digital signal processing with the Field-Programmable Gate Array (FPGA) controlling chip and Very-High-Speed Integrated Cir...
We report on absolute measurements of saturated-absorption line-center frequencies of room-temperature trifluoromethane using a quantum cascade laser at 8.6 μm and the frequency modulation spectrosco...
Lasing and self-frequency doubling are achieved in a millimeter-sized laser-active whispering-gallery resonator made of neodymium-doped lithium niobate. A low-cost 808-nm laser diode without external ...
This study is a Phase I/II , open label,non randomized, prospective study to determine the safety of human embryonic stem cell derived Retinal pigmented epithelium (hESC RPE) sub retinal i...
The purpose of the study is to find out which is a better treatment for diabetic macular edema (DME): laser alone, laser combined with an intravitreal injection of triamcinolone, laser co...
The objective of this study is to determine whether the Air Barrier System device reduces airborne particulate and airborne colony forming units present at a surgery site.
To determine the optimal treatment frequency of 308-nm excimer laser for vitiligo and identify the key clinical variable(s) associated with the treatment efficiency under the optimal treat...
Laser-assisted intracytoplasmic sperm injection (ICSI) has been suggested as a more effective alterative to conventional ICSI when this method of insemination is indicated for patients und...
A technique utilizing a laser coupled to a catheter which is used in the dilatation of occluded blood vessels. This includes laser thermal angioplasty where the laser energy heats up a metal tip, and direct laser angioplasty where the laser energy directly ablates the occlusion. One form of the latter approach uses an EXCIMER LASER which creates microscopically precise cuts without thermal injury. When laser angioplasty is performed in combination with balloon angioplasty it is called laser-assisted balloon angioplasty (ANGIOPLASTY, BALLOON, LASER-ASSISTED).
Ventilatory support system using frequencies from 60-900 cycles/min or more. Three types of systems have been distinguished on the basis of rates, volumes, and the system used. They are high frequency positive-pressure ventilation (HFPPV); HIGH-FREQUENCY JET VENTILATION; (HFJV); and high-frequency oscillation (HFO).
Voluntary cooperation of the patient in taking drugs or medicine as prescribed. This includes timing, dosage, and frequency.
Techniques using laser energy in combination with a balloon catheter to perform angioplasty. These procedures can take several forms including: 1, laser fiber delivering the energy while the inflated balloon centers the fiber and occludes the blood flow; 2, balloon angioplasty immediately following laser angioplasty; or 3, laser energy transmitted through angioplasty balloons that contain an internal fiber.
Somatosensory evoked potentials generated through the application of HEAT to the SKIN with a LASER. They are often used clinically to assess the function of the central nociceptive system and in diagnosing NOCICEPTIVE PAIN.