How does a mode locked laser work?
How does a mode locked laser work?
Most mode-locked lasers are continuously pumped, often with a laser diode. The pump source then continuously supplies energy to the gain medium, while the circulating pulse extracts energy in regular time intervals.
What is the active region in semiconductor laser?
The active region of the laser diode is in the intrinsic (I) region, and the carriers (electrons and holes) are pumped into that region from the N and P regions respectively.
What is the active medium of semiconductor laser?
The active medium of the semiconductor laser is a PN junction. In this laser, mirror is not used as in other resonator or cavity for optical feedback to sustain laser oscillation. In this case, the reflectivity due to the refractive indices of two layers of a semiconductor laser is used for optical feedback.
What are the different ways of locking a mode of a laser?
In a simple laser, each of these longitudinal modes will oscillate independently. When each mode is made to oscillate at a fixed phase between each other, the laser is said to be mode locked. There are three methods of mode locking. These are, namely, active, passive, and hybrid.
Why are semiconductors used in lasers?
Semiconductor Laser is used for a variety of applications by taking advantage of characteristics that include straightness, small emission spot size (several um), monochromaticity, high light density, and coherence.
What is pumping in semiconductor laser?
Electrical pumping is used for gas and semiconductor lasers. It is realized by allowing a current (continuous dc current, radio frequency rf current or pulsed current) to flow through a conductive medium, such as an ionized gas or semiconductor.
What is active system in laser?
The active laser medium (also called gain medium or lasing medium) is the source of optical gain within a laser. The gain results from the stimulated emission of photons through electronic or molecular transitions to a lower energy state from a higher energy state previously populated by a pump source.
What is active center in laser?
This medium decides the wavelength of laser radiation. Active mediums contain atoms which can produce more stimulated emission than spontaneous emission and cause amplification they are called “Active Centers”.
What are the types of semiconductor laser?
GaAs (gallium arsenide)
What is semiconductor laser and its types?
A semiconductor laser (LD) is a device that causes laser oscillation by flowing an electric current to semiconductor. The mechanism of light emission is the same as a light-emitting diode (LED). Light is generated by flowing the forward current to a p-n junction.
