Photo acoustic spectroscopy of beta amyloids - research overview Group Meeting February 08

OTDR pulse width: 100ns-1μs Scope detector 10% fiber splitter Erbium Amplifier 90% PZT RF Amplifier 24V+ Voltage source referencePhoto-acoustic signal First setup goal –generating and characterization of pa signal Wavelength – 1550 nm 1. OTDR

Tunable Laser Polarization controller Modulator Function Generator Erbium Amplifier x2 Scope PZT RF Amplifier x3 24V+ Voltage source detector fiber splitter Reference 95% Signal 5% 2. Tunable Laser Wavelength nm

~5 micro second PZT

Water: Abs coefficient =11.6 cm^-1 heat capacity = J cm-3 K-1 Thermal expansion = /K ethanol: Abs coefficient =5.7 cm^-1 heat capacity = J cm-3 K-1 Thermal expansion = /K

There is a change of 0.28% in sound velocity for a percent change of glucose concentration

, ,000 UVvisibleNear-IRIR nm 1550 peptidic bond ( nm) aromatic residues (~280nm) starching vibration of aromatic residues (3.3, 6.25,6.6 μm ) starching vibration of amide bond ( μm ) bending vibration of aromatic residues ( μm) Over tones ( ) Spectrum

Technion experiment : Nd:YAG fourth harmonic 266nm laser: 1.Insulin

2.lysosin 3.Beta amyloid

opo experiment: OPO -optical parametric oscillator

Zoom in on first peak 1. insulin 2. water Wavelength ~1660nm

Goals for the short future  improving the sensitivity of the measurements  Defining the concentration and absorption coefficient of solutions by pa measurement  Finding the amyloids over tones spectra, and characterize its pa signal  Examine the ability of performing pa measurements in the MIR  Completing the simulation of the pa signal