Talk:Mode locking

This article is about mode-locking in lasers, which is fine, but mode-locking is a more general topic applicable to all sorts of non-linear oscillatory systems. Maybe someone can write a more general description for mode locking and perhaps this article can be retitled Mode-locking (lasers), or something similar, to better reflect its content. 3piecesuits (talk) 00:39, 24 June 2011 (UTC)[reply]

The description of the relationship between bandwidth and minimum achievable pulse length was worded in a way that sounded causal; I have amended it to correct this, instead emphasizing that the relationship between bandwidth and pulse length is instead one of _consistency_. To clarify this further I've added an extra sentence at the end pointing out that the pulse width can always be further shortened with a modulator, though at the cost of increasing the measured bandwidth. User:Anonymous 7:23, 2010 Sept 7 (EST). —Preceding unsigned comment added by 140.247.122.180 (talk)

Why is frequency ν rather than f? Is this a standard I am unaware of? -- SGBailey 10:06, 2005 Apr 22 (UTC)

Both notations are often used. It is not a bad idea to use ν for optical frequencies and f for noise frequencies, particularly in a context where both may be confused, e.g. when discussing noise of mode-locked lasers. RPaschotta 20:57, 27 Apr 2005 (UTC)

I think this page desperately needs discussion of SESAM modelocking. I can try to throw some stuff together. Patrick Berry 01:57, 4 April 2006 (UTC)[reply]

I want to write a more detailed description of active modelocking for Nd:YLF (our system), or Nd in general. What lasers are typically modelocked actively? Everbody does it passively now (KLM, SESAM, and see: EKSPLA)? With positive GVD no solitons form, what happens in our laser? I especially wonder about shortening the cavity shortens the pulses acording to the auto-correlator, it would mean the the red part of the pulse has less loss. Is SPM important for this effect? Arnero 13:10, 28 February 2007 (UTC)[reply]

I think it would be best to explicitly mention the phase velocity in a medium $v_{p}={\frac {c}{n_{g}(\omega )}}$ instead of the speed of light in vacuum, since I know not of laser cavities without a gain medium.. --Dropsciencenotbombs (talk) 11:58, 22 September 2009 (UTC)dropsciencenotbombs[reply]

The sourcing of this article is clearly self-promotion, and, what is more, from articles which are not moire central to the field than many others. This must be amended considerably. --Nevyn72 (talk) 12:48, 27 January 2010 (UTC)[reply]

Agreed, I note that all of the references involve this Zhang character, so I will cut down his stuff to the area he seems involved in, graphene. --Anuran (talk) 12:15, 24 June 2010 (UTC)[reply]

section removed

I removed the following section as it is oddly chatty and not terribly informative about the actual subject of modelocking - 75.164.27.200 (talk) 20:40, 7 December 2009 (UTC) :[reply]

Neodymium as a dopant has a lot of laser lines. A group of 8 lines lies between 1050 nm and 1080 nm. If the host material is YAG, these lines have width of 0.5 nm. If the host is YLF, the lines have width of 1 nm. If the host is glass, the lines merge into one continuum of 38 nm FWHM (Broad-spectrum neodymium-doped laser glasses for high-energy chirped-pulse amplification; Greg R. Hays, Erhard W. Gaul, Mikael D. Martinez, and Todd Ditmire; Applied Optics, Vol. 46, Issue 21, pp. 4813-4819 ). Single stack laser mirrors have high reflectivity within a 30 nm range. For the crystal host-materials an etalon selects the main laser line and a Gires-Tournois-Interometer compensates the GVD. For the glass host the same techniques as for Ti:Sa lasers can be used. In the crystal hosts the gain bandwidth allows for pulses of about 1 ps. Gain-loss optimization between the gain medium and the typical 10000 ps modulation period of the AOM then leads to 100 ps pulses at 100 % modulation depth. The round-trip frequency of the cavity must be adjusted with 1 in 1E6 precision onto the AOM standing wave frequency( [1], [2], REVIEW OF SCIENTIFIC INSTRUMENTS 78, 013105 2007 ). For this the diffracted light from the AOM is detected by a photodiode, and minimized. Depending on the sign of the detuning the relative phase between the diffracted signal and the reflection on the surface of the AOM changes and can be detected by the interference of the two on a small photodiode array. Any drift in this interferometer leads to drift of the phase, while the cavity length drift leads to amplitude drift with π jumps of the phase.

frequency modulation (FM) mode-locking

In the section about FM mode-locking it says that the frequency of the light is changed when it passes through a device based on the electro-optical effect. As far as I understand it not the frequency of the light changes (impossible by altering the refractive index) but rather the resonance frequency of the resonator is changed which then attenuates the waves with the wrong phase. Correct me if I am wrong but if I am right that should be changed. — Preceding unsigned comment added by 178.191.139.212 (talk) 23:47, 19 February 2014 (UTC)[reply]

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