02:21 <sb0> rjo, why are ion trap lasers not built like this? http://repairfaq.cis.upenn.edu/Misc/Blu-ray/site1/optics.html

06:00 <sb0> rjo, what sort of mirror reflectivity should I be looking at for a FP cavity used for locking a cooling laser?

15:19 <rjo> sb0: what do you mean by "built like this"? how many orders of magnitude in frequency stability do you think those modules are away from what an ion trap needs?

15:21 <rjo> sb0: for locking? make it wide enough so that you can lock to it and narrow enough so that it give you sufficient precision.

15:58 <sb0> rjo, many, but that's not what they are designed for. i mean they are very compact.

15:59 <sb0> what is the typical reflectivity used?

16:19 <rjo> compactness means you can't align the optics, can't exchange/debug the electronics in there. and compactness also directly prevents getting the frequency stability and being able to tune temperature etc.

16:19 <rjo> .99-.999 is typical if you want a ~1MHz bandwidth

16:21 <rjo> but it depends of length.

16:24 <sb0> how does it prevent frequency stability?

16:26 <sb0> and bluray manufacturers certainly have (and have solved) the problem of alignment as well, haven't they?

16:28 <rjo> small cavities imply very inconvenient parameters for mirrors and piezos to tune.

16:29 <rjo> no. they only care about the alignment within that assembly. w.r.t. outside they don't care or have motors.

16:29 <sb0> that reflectivity isn't too bad, at least it's in the ballpark of high quality mirrors used in relatively inexpensive co2 laser cutters

16:29 <rjo> and their solution to the alignment problem is a very big machine.

16:30 <sb0> if it's compact, you can just move the whole thing to align it with the in-vacuum parts

16:30 <rjo> you do know that that's a very different wavelength.

16:31 <rjo> price is irrelevant. because something is cheap doesn't mean it's good. nor is the reverse true. i don't understand why your thoughts circle around the price of something on taobao all the time.

16:35 <rjo> but you can't align it if you just built it or want to change the diode.

22:43 <whitequark> sb0: back

22:43 <whitequark> some script at freenode misdetected me as a bot