Recent content by gujax

Thank you Claude and Jeff. You may be correct about the graylevels Claude but I want to compare "same amount of signal" either by integrating or by accumulating. In your case comparing 255 to n*255 is unfair - I think. I was meaning to compare X and n*Y such that X= n*Y and then compare their...

In CCD detection, is integration better than accumulation Hi, I have carefully experimented and found this to be a true observation with CCD detection in general. Signal to noise improves if one integrates a signal (e.g. over x seconds) versus accumulating over many short integration times...

Hmm, interesting! Are you talking about non-optically pumped diode lasers in which an external current induces lasing? But then you are now no more really talking about a closed system. The above statement is strictly true for a radiative closed system. If you bring in particles from outside...

Hi DavidSosa, Sorry did not read your message until today. I am using the dynamic light scattering to look at blood vessels in a tissue non-invasively. This will use a light source to illuminate the tissue using a laser and a detector to detect backscattered light with a PMT and a correlator to...

As an example: Normally one detects light with a photo detector. A photo detection is converted into electronic signal after some kind of filtering (or whatever is the frequency response of the system). Physically for a square-law detector the Fourier transform (FT) of a correlation provides the...

Thank you again Cthuga, Got it this time. To summarize my understanding: 1. At time t1, the field scatters off a particle and say also off a stationary medium such as wall of a tube carrying the particle. 2. The two will interfere because the two fields interfere in times less than coherence...

I do know that if the particles diffuse in a very viscous medium, the intensity autocorrelation signal does extend out to several milliseconds... Thank you for thinking this over. I appreciate it. Also this time I must say sorry I am getting confused, but why is \phi_l(at time t=0) , same as...

Thanks Cthugha, That was really really helpful. A big thank you. I have to think more about your emphasis on amplitude rather than on the phase for dynamic light scattering (DLS) measurements. My next question would have been: If phase is not important for DLS, then why have formulations in...

Hi, 1. I am studying dynamic light scattering in which one experimentally measures intensity correlation i.e., <I(t)I(t+tau)>. Therefore, if the detector looks at a scattering signal from a solution of particles undergoing Brownian motion, under right experimental conditions one can detect the...