Ruby Lab

Part 1 – Fall 2011

John and Kevin

Two ways to make the lifetime measurement

nsec

nsec nsec

Time domain

Frequency domain

Slide from Dr. Clegg

Frequency domain lifetime measurement( ) cos( )o E EE t E E t ( ) cos( ) o E Sample EF t F F t

2

1

1 ( )

o

E

o

F

FM

E

E

1tan ( ) Sample E

Slide from Dr. Clegg

Ref-in

Lock-in input

excitation filter

Setup

J Fluoresc. 2006 Nov;16(6):793-807

Experiment 1 – Pulse Excitation

Experiment 2,3 – Sinusoidal Excitation – Lock-in

( ) cos( ) o E Sample EF t F F t

( ) cos( ( )) o E E SampleF t F F tPhase that you measure

Multimeter

Lock-in Amplifier

Fo

Fω ( ) Meas E Sample

Procedure:

1) Measure Rhodamine B.

-Plug into equation for M. You know (Fω and Fo) because you measured them. You know Rhodamine B’s lifetime and the modulation frequency. You can solve for Eω/Eo.

-Plug into equation for φ. The phase you measured for Rhodamine B is φE.

2) Measure Ruby

-Plug in the values (Fω and Fo) to the equation for Mand solve for the lifetime since you know Eω/Eo and the modulation frequency

-Plug in the phase that you measured for ruby φmeas.

Experiment 2,3 – Sinusoidal Excitation

2

1

1 ( )

o

E

o

F

FM

E

E

,Remember:

( ) cos( ( )) o E E SampleF t F F t

1tan ( ) Sample E

meas E Ruby

R

Θ

E(t)

Ref(t)

ΘRef(t)

F(t)

R

R=Ew

R=Fw

Eo

Fo

DC=Eo

DC=Fo

Rhodamine B

Ruby

Θ=ΘE

Θ=ΘE-ΘSample

More Details on the Lock-In…Only if you are interested

Drawn by Kevin Teng