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Laser linewidth from high-power high-gain pulsed laser oscillators, comprising line narrowing optics, is a function of the geometrical and dispersive features of the laser cavity. [29] To a first approximation the laser linewidth, in an optimized cavity, is directly proportional to the beam divergence of the emission multiplied by the inverse ...
Pulsed Nd:YAG and Er:YAG lasers are used in laser tattoo removal and laser range finders among other applications. Pulsed lasers are also used in soft-tissue surgery. When a laser beam comes into contact with soft-tissue, one important factor is to not overheat surrounding tissue, so necrosis can be prevented. [ 3 ]
The PRF is normally much lower than the frequency. For instance, a typical World War II radar like the Type 7 GCI radar had a basic carrier frequency of 209 MHz (209 million cycles per second) and a PRF of 300 or 500 pulses per second. A related measure is the pulse width, the amount of time the transmitter is turned on during each pulse.
Using this equation, the minimum pulse duration can be calculated consistent with the measured laser spectral width. For the HeNe laser with a 1.5 GHz bandwidth, the shortest Gaussian pulse consistent with this spectral width is around 300 picoseconds; for the 128 THz bandwidth Ti:sapphire laser, this spectral width corresponds to a pulse of ...
The duty cycle expresses the pulse width as a fraction or percentage of one complete cycle. Pulse width is an important measure in radar systems. Radars transmit pulses of radio frequency energy out of an antenna and then listen for their reflection off of target objects. The amount of energy that is returned to the radar receiver is a function ...
FROG is simply a spectrally resolved autocorrelation, which allows the use of a phase-retrieval algorithm to retrieve the precise pulse intensity and phase vs. time. It can measure both very simple and very complex ultrashort laser pulses, and it has measured the most complex pulse ever measured without the use of a reference pulse.
Unlike the giant pulse of a Q-switched laser, consecutive pulses from a mode-locked laser are phase-coherent; that is, the pulses (and not just their envelopes) are identical and perfectly periodic. For this reason, and the extremely large peak powers attained by such short pulses, such lasers are invaluable in certain areas of research.
These two lower-frequency beams are called the "signal" and "idler", respectively. This light emission is based on the nonlinear optical principle. The photon of an incident laser pulse (pump) is, by a nonlinear optical crystal, divided into two lower-energy photons. The wavelengths of the signal and the idler are determined by the phase ...