Talk:Q-switching

Even with pulse-pumped lasers (such as flashlamp-pumped) you use a Q-switch to reduce the length of the pulse (You pump it for several milliseconds, then use the q-switch to get a pulse of only 10-50ns or much shorter). Talking about it in only the context of CW lasers is misleading. JohnFlux 14:45, 5 August 2005 (UTC)

Article is confusing and poorly worded for simple concept
Definition = ''(Quality switch) An optical valve in a laser that prevents light from transmitting outside the resonating cavity. The Q switch allows for the build-up of energy before it is switched open to allow light to move out.'' —Preceding unsigned comment added by 69.152.32.30 (talk • contribs) 01:19, 9 April 2009


 * "Optical valve" doesn't really appeal to me as a description. A Q-switch works just the opposite of what you have described: It does not prevent light from transmitting outside the cavity. Rather, it removes light from the cavity, preventing any light from building up there. Since the light can't build up, there is nothing to de-excite the electrons in the gain medium. As the gain medium is pumped, more and more electrons become excited, and the optical gain increases, reaching a much higher level than it would if there were light in the cavity. When the Q-switch is turned off, light begins to build up. Because of the much higher than usual gain, the light builds up very fast, to a much higher intensity than usual. It quickly depletes all the excited electrons, so the laser produces a relatively short, intense pulse.--Srleffler (talk) 03:44, 10 April 2009 (UTC)
 * Thanks. --70.240.146.164 (talk) 18:32, 20 April 2009 (UTC)

Also many lasers are not cw as stated. Ruby is not, but it can be q switched. More care is needed.Claustro123 (talk) —Preceding undated comment added 23:26, 6 March 2013 (UTC)

Too Technical
This article is too technical. I'm a college educated person and I find several things are totally unexplained in this article. Some examples:

used in a double pass manner to half its thickness (Active Q-switching section). Excuse Me?

distinguish between ingoing and outgoing pulses. What ingoing pulse?

What is 'Jitter' (Variants section)?

Crusty007 20:38, 18 March 2007 (UTC)


 * See Jitter for the latter.--Srleffler 22:33, 18 March 2007 (UTC)

I have a physics degree and I'm doing a masters in photonics - having just come across Q-switching in lasers (a similar principal exists for mechanical/electrical oscillators), I was a bit disappointed by the lack of equations here... I'm not necessarily looking for exact real-world equations at all, just some which can quantitatively describe Q-switching behaviour - for example, relating the Q factor to stimulated emission and stored energy, describing how these change as the Q-factor is increased. Essentially, I'm saying that the basics in this article have been overcomplicated, while the complicated parts aren't there at all. If I remember, I'll add these in when I get round to learning/deriving them.

87.112.222.13 (talk) 23:52, 11 November 2010 (UTC)

Paragraph removed
I removed the following from the active q-switching section. It is unclear, and doesn't really seem to concern active Q-switching per se, but rather other applications such as cavity dumping, regenerative amplification, etc.--Srleffler 22:41, 18 March 2007 (UTC) "Three cavity configurations are possible. One device in the middle of the cavity would allow to couple pulses to two different ports. More often the device is placed near one end mirror and is used in a double pass manner to half its thickness. If one needs to be able to now distinguish between ingoing and outgoing pulses an external Faraday isolator (second possibility) or switch (third possibility) is added."