Mechanism for self mode locking in Ti:sapphire

[Chuckwagon]

I am a PHD student doing research on Ti:sapphire lasers so that when I enter the lab I have a full understanding of workings of the laser. I was wondering if anyone could go over the finer points of the mechanism of self mode locking in a Ti:sapphire laser? I have a picture in my head that involves the Kerr effect where intensity of the pump beam affects the index of refraction due to higher order effects. I understand that mode locking is just a locking of the phase of all the modes in such a way that there is constructive interference between modes producing pulses related to the width between modes. However, I am uncertain on the details especially the Fourier Transform from the time domain into the frequency domain that I was told would clarify things. Even if someone could direct me to an article or book that describes this it would be greatly appreciated.

 

[BigJDubs]

The self mode-locking of a Ti:sapphire laser is a complex process that involves many different components. The mechanism starts with the Kerr effect, where the intensity of the pump beam affects the index of refraction due to higher order effects. This creates a nonlinear refractive index, which in turn modifies the group velocity of the light, resulting in a shift in the frequency of the light. This shift in frequency causes the modes of the laser to move in and out of phase with each other, leading to constructive and destructive interference. This process leads to a narrowing of the spectrum of light, which is known as spectral hole burning. The spectral hole burning results in a series of narrow spectral lines, which can be used to create a self-mode-locked laser. The process works by creating an optical cavity in which the laser beam bounces back and forth between a pair of mirrors. The optical cavity can be tuned to the frequency of the spectral lines, so that the laser beam will be repeatedly reflected back and forth between the two mirrors. This creates an interference pattern at the output of the laser, with each peak in the pattern corresponding to one of the spectral lines.The Fourier Transform is then used to convert this time-domain output into a frequency-domain signal. This signal contains information about the frequencies of the spectral lines, and can be used to accurately determine the parameters of the laser. By tuning the optical cavity to the desired frequency, it is possible to achieve self-mode-locking, where the laser produces a series of pulses instead of a continuous beam.For more detailed information on the specifics of self-mode-locking in Ti:sapphire lasers, I recommend reading the book "Ti:Sapphire Lasers" by Robert L. Byer. This book provides a comprehensive overview of the science and technology behind Ti:sapphire lasers, including an in-depth discussion of the self-mode-locking process.