Sir thanks for your valuable reply,
1. Initially I was using 32-bit FDTD in that 2D transverse tab Half width is mentioned even for gaussian source, but now I am using 64-bit FDTD evaluation version.
2. I attached the updated design file, DFT option in the simulations and now I can vary the wavelength range.
3. In previous attachment contains design and previously published paper. In that paper design consists of two waveguides and one resonator (cavity/sensing region). First sio2 slab is created, then placed the silicon rods of placed by using PWE calculated band gap based on that radius= 0.2a, sensitive region radius is (> 0.2a) little higher than other silicon rods. Gaussian source with Sine-Modulated Gaussian Pulse is used and observation line is used. Procedure is based on previous published paper I am following to analyse the results. The sensitive region RI is changed based on the following three cases i) first air RI = 1, ii) Second Cancer cell RI (C) = 1.399, iii) Normal cell RI N = 1.385 used. Expected result from these three cases are to get different resonant peaks (by default resonant wavelength is also changes) for each case in power spectrum, if result is getting different peaks for each case, then the design is working properly. Still, I am facing problem of not shifting the resonant wavelength.
4. For Sine-Modulated Gaussian Pulse tab how to find Time Delay (Sec) and FWHM (Sec).