Editing Mode locking (section)

==Locking mechanism of laser cavity==
 {{uncited section|date=December 2023}}
[[Monochromatic light]] is the property of the laser depends on the fundamental working principle of the laser which contains frequency-selective elements. For example, in [[Laser diode|diode lasers]], [[Resonator|external mirror resonators]] and [[Diffraction grating|gratings]] are those elements. With the help of these elements, frequency selection leads to a very narrow spectral emission of light. However, when observed closely, there are frequency fluctuations that occur on different time scales. There can be different reasons for their origin, such as fluctuation in input voltage, acoustic vibration, or change in pressure and temperature of the surroundings. So, to narrow down these frequency fluctuations, it is necessary to stabilize the phase or frequency of the laser to an external extent. Stabilizing laser properties using any external source or external reference is generally called "laser locking" or simply "locking".

=== Error signal generation ===
The reason for generation to create error signals is to create an electronic signal which is proportional to the laser's deviation from a particular set frequency or phase, which is called a "lock point". If the laser frequency is large, then the signal is positive; if frequency is very small, then the signal is negative. The point where the signal is zero is called a lock point. Laser locking based on an error signal which is a function of frequency is called frequency locking and if the error signal is a function of phase deviation of laser then this locking is referred to as phase locking. If the signal is created using an optical setup involving references like frequency references, then by using the reference, the optical signal is directly converted into frequencies which can be detected directly. The other way is to record the signal using a photodiode or camera and further change this signal electronically.