Generation of Ultra-Short Optical Pulses

Here Wq is the centre angular frequency. The evaluation of this expression involves the same type of mathematics as that used for calculating the spectral intensity distribution from a grating, and we have 

11) expresses an optical sinusoidal carrier wave of frequency Wq, which is amplitude-modulated in time according to (9.12). The light intensity is proportional to A (t), and in Fig.9.19 the intensity for the case of 7 locked modes is given. 

The phase relation (9.9) causes the continuous partial waves to interfere constructively to give short pulses separated in time by 

A common way to mode-lock a dye laser that is pumped by an ion laser is to use synchronous pumping. An actively locked ion laser with the same cavity length as the dye laser is then used (the length of the dye-laser 

In passive mode-locking a thin (0.1mm) saturable absorber (special dyes) is used in the cavity. For sufficiently high light intensities the absorption of the substance is reduced (bleaching). Such intensities are obtained at a mode-locking with associated pulse formation, whereas all unrelated 

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