Re: questions about light

"laura" <laura.brandusan@xxxxxxxxx> writes:

Hi all,

I face new problems now:

New homework? :)

1. I've did read about photodiodes and it seems that the response time
is about 100 ns. Can I measure the fluctuations in the intensity of a
light ray which occurs at smaller intervals of time (pico seconds for
instance)?

You can get photodiodes with a response to 100 GHz or more. That's 10 ps.
A second mortgage may be required to pay for one though. :)

2. Regarding the wave-length. Suppose that I have n rays which have
different wave-lengths (w1, w2, ...wn). I want to change their
wave-lengths to (w1+x, w2+x, ...wn+x), where x is a fixed quantity that
I know. How can I do that?

How large is x?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
.

Relevant Pages

  • Re: questions about light
    ... In my case the light is travelling through some optic fibers. ... These fluctuations can appear at very small intervals of ... measuring the changes in the intensity of a light ray? ...
    (sci.optics)
  • how to measure the fluctuations in the intensity of a light ray?
    ... the intensity of a light ray? ... These fluctuations can appear at very ... What devices are for measuring the fluctuations in the intensity of ...
    (sci.physics.electromag)
  • Re: Is light bending a function of wavelength?
    ... >>It does not apply to refraction in media, and I never said it did. ... >>The energy density of a light ray is proportional to its intensity ...
    (sci.physics.relativity)
  • Re: New original Song - Please critique
    ... homework). ... The guitar tracks are great. ... It's a heavy song, but your ... know it's hard to get that intensity when you record at home. ...
    (alt.guitar)
  • Re: Toaster to Generate Random Numbers
    ... >]A further problem I have is that intensity of the light coming from ... >]quasars has 1/f noise fluctuations. ... >]the experiment, but then again, Quasars are very bright. ...
    (comp.security.misc)