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Unformatted text preview: 1 125:431 Introduction to Optical Imaging Spring 2007 Problem set #2- Due Tuesday Feb. 6 Related readings: Hecht Sections 3.3 and 13.1, and reference posted on WebCT under resources for Pb set 2 1. Consider again the E field vector z t kx E y t kx E E o o ˆ ) cos( ˆ ) cos( ω ω − − − = r which satisfies the wave equation: 2 2 2 t E E o o ∂ ∂ = ∇ r r µ ε Write an expression for the Poynting vector average, <| S |> T , calculated over a time interval T, such that ω T>> 1 2. A researcher observing green fluorescent protein detects an average of 100 counts per pixel on a CCD camera in her microscope. The data acquisition time was 10ms. a. Assuming that every count on this CCD correspond to 5 photons at 514nm, what is the average optical power (in watts) measured per pixel? b. Assuming that the detected photons follow a Poisson probability distribution, and that there is no other significant source of noise in the system, what would you estimate the signal-to-noise ratio to be per pixel? c. How would you improve the signal to noise ratio? 3. This problem was adapted from the paper entitled: “A computer model of laser action in the teaching of computational Physics” by D.G.H. Andrews and D.R. Tilley, Am. J. Phys, 59 (6); 536-541, June 1991 ( posted on WebCT in the resources link, Resource for Problem Set 2 ) Consider the following 4 level system (see figure) with the following rate equations: dN 1 /dT= -N 1 /T 1 + A 21 N 2 + B 21 (N 2-N 1 )W, for the lower state 1, 2...
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This homework help was uploaded on 04/03/2008 for the course BIOMEDICAL 431 taught by Professor Boustany during the Spring '07 term at Rutgers.
- Spring '07