Lab 10: Time & Frequency Domain Fluorescence - Lifetime Measurements, Lab Reports of Physics

Download Lab 10: Time & Frequency Domain Fluorescence - Lifetime Measurements and more Lab Reports Physics in PDF only on Docsity! Physics 598OS Optical Spectroscopy (Fall 06) Clegg/Chao/Liu Lab 10 - Time and Frequency Domain Fluorescence Lifetime Measurements Report Questions Here are the report questions for you’re lab 10 writeup. If you would like more background information than provided in the handouts, check the references below. References • Danielle E. Chandler, Zigurts K. Majumdar, Gregor J. Heiss and Robert M. Clegg, “Ruby Crystal for Demonstrating Time- and Frequency-Domain Methods of Fluorescence Lifetime Measurements.” J. Fluoresc (2006). advanced online: http://www.springerlink.com/content/t04m0j16235123v0/?p=91cb17d2f6f247a9be824d5b2633d0b1&pi=2 • Valeur, Chapter 6. • Lakowicz, Chapter 4, 5. Experiment I – Time Domain Measurement Q1) a) Crop your time-domain trace to show just a single exponential decay from your time-domain time trace and fit it to the following exponential decay form. Show a plot of your fit along with your fit parameters ]/)(exp[)( 0 τttAtF off −−= b) What is your measured lifetime? Here we assumed an exponential decay without deconvoluting the fluorescence signal from the excitation waveform. What could be possible sources of error? Hint: what artifacts could chopping the excitation light produce. Is the excitation light a perfect square wave? Why was it important to focus the light on the chopper blades? Experiment 2 – Frequency Domain Measurements We present here again the formulae for the modulation and phase: 2 1 1 )(1 1 / /)( ωτ ω + =≡ o o EE FFM (1) )arctan(ωτφ = (2) where the excitation E and the emission F is by )cos()( )cos()( 1 1 φ ω ++= += wtFFtF tEEtE o o Q2) The R that you measured from the lock-in is the modulation depth of the fluorescence signal, F1, while the phase θ from the lock-in is φ plus some arbitrary shift which you’ll need to account for using the rhodamine measurement. a) The phase φ is given by RhodamineRuby θθφ −= (3) - 1 -