Is achieved by using saturable absorber?

The main applications of saturable absorbers are passive mode locking (i.e., as mode locking devices) and for Q switching of lasers, i.e., the generation of short optical pulses.

How do you mode lock a laser?

Such a laser is said to be ‘mode-locked’ or ‘phase-locked’. These pulses occur separated in time by τ = 2L/c, where τ is the time taken for the light to make exactly one round trip of the laser cavity. This time corresponds to a frequency exactly equal to the mode spacing of the laser, Δν = 1/τ.

What is reverse saturable absorption?

Reverse saturable absorption. A class of nonlinear absorbers in which the excited state absorption is large compared to the ground state absorption can undergo a process called reverse saturable absorption (RSA), also known as reversible saturable absorption.

What is saturable process?

Drug absorption is the process by which a drug molecule moves from the site of administration to the systemic circulation. Following intravenous administration, there is no absorption process since the drug is directly introduced into the blood stream. This is called saturable drug absorption.

What is passive mode locking?

Compared with active mode locking, the technique of passive mode locking allows the generation of much shorter pulses, essentially because a saturable absorber, driven by already very short pulses, can modulate the resonator losses much faster than any electronic modulator: the shorter the circulating pulse becomes.

What is the importance of laser locking mode?

Mode locking is the most important technique for generating pulses with picosecond and femtosecond durations. When a laser is mode locked, one or sometimes several pulses are circulating in the laser resonator.

What is the advantage of mode locking?

Advantages of fundamental mode locking are that possible instabilities of harmonic mode locking are avoided, and that the laser setup is usually more compact. On the other hand, harmonically mode-locked lasers have a potential for lower laser noise.

What is a saturable process?

What is a saturable drug?

By: Nathan Teuscher. Drug absorption is the process by which a drug molecule moves from the site of administration to the systemic circulation. Following intravenous administration, there is no absorption process since the drug is directly introduced into the blood stream.

What is the meaning of saturable?

: capable of being saturated.

What is the use of mode locking?

Mode locking is a technique used to obtain ultrashort pulses from lasers. Lasers that are mode locked are capable of producing pulses with pulse widths in the order of sub-pico seconds, or even femtoseconds.

What is active and passive mode locking?

Passive Mode Locking In a passively mode-locked laser, the loss modulation is done by a saturable absorber, such as a SESAM. This mechanism allows us to generate shorter pulses than with active mode locking. The reason is that the shorter the circulating pulses become, the faster the loss modulation.

What are the applications of saturable absorbers in lasers?

There are also artificial saturable absorbers (see below), where there is no real absorption, but an optical loss which decreases for increasing optical power. The main applications of saturable absorbers are passive mode locking (i.e., as mode locking devices) and for Q switching of lasers, i.e., the generation of short optical pulses .

Can a saturable absorber be used as a mode locker?

The device possesses ultrafast optical properties comparable to that of the industrial standard semiconductor saturable absorber mirror (SESAM). Passively mode-locked picosecond fiber lasers in different configurations are demonstrated using SAINTs as mode lockers.

Which is better a fast or slow absorber for passive mode locking?

A fast absorber is not necessarily better suited e.g. for passive mode locking; in fact, self-starting mode locking is more easily achieved with a slow absorber. The saturation parameter of a slow saturable absorber (e.g. in a mode-locked laser) is the ratio of the incident pulse fluence to the saturation fluence of the device.

What causes mode locking in a laser resonator?

Here, the laser resonator contains some kind of mode locking device (mode locker) – either an active element (an optical modulator) or a nonlinear passive element (a saturable absorber ), which causes the formation of an ultrashort pulse circulating in the laser resonator.