Part IV: Optical Spectroscopy of Solids

Atilla AYDINLI

Outline

Experimental Setup Monochromator PMT Laser

Elements of Raman Spectroscopy Introduction to Photoluminescence

Spectroscopy

U1000

U1000

Slits

Reflection Grating

Transmission Grating

Grating Equation

Grating Equation

)sin(sincos

sinsin

)sin(sin

Gm

Gm

dm

Grating Equation

Littrow Configuration

orderzeroorreflectionspecular

formirrorm

dm

)(0

)sin/arcsin()(

sin2dm

Grating Equation Deviation angle

Scan angle

Grating equation for mounts

K2

2

sincos2 Kdm

Sin-Drive; Cosecant-Drive

L

xKdm

L

xcos2sin

Diffraction Order

Order Overlap

Dispersion Angular

Dispersion

Linear Dispersion

secsec

cosGm

d

m

d

m

d

dD

sec''' Gmrd

drDr

Dispersion Reciprocal Linear Dispersion (nm/mm)

2.43 nm/mm for U1000 w/ 1800 g/mm grating

'

cos

mr

dP

Resolving Power

/2

2sinsin

/)sin(sin

/)sin(sin

WR

WR

NdR

mNR

MAX

Focal Length and F/#

F/# Matching

Over match: Loss of signal Under match: Loss of resolving

power Choose collection optics geometry

to match it to the F# of the monochromator

PMT

PMT

Spectral Responsivity

PMT

Transfer Function/Throughput

Polarization dependent Wavelength dependent Ideal light source? No! Use a black body at a known temp Use calibrated W lamp With known incident spectral light

density measure output and calculate T. Important for PL exp not so for Raman.