Photothermal Spectroscopy Lecture 2 - Applications Aristides - - PowerPoint PPT Presentation

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Photothermal Spectroscopy Lecture 2 - Applications Winter College on Optics

Aristides Marcano Olaizola (PhD) Research Professor Department of Chemistry Delaware State University, US

Outlook 1. Optical characterization of matter. 2. The place of photothermal spectroscopy 3. Achromatic character of the mode- mismatched configuration. 4. NIR Photothermal spectroscopy 5. Photothermal-absorbance-fluorescence spectrophotometer. 6. Photothermal spectroscopy of fluorescence and scattering samples. 7. Perspectives.

Material samples exhibit generally more than

• ne type of effect upon interaction with light

Transmitted light Incident light Reflected light Scattered light Absorption of light

Photoacoustic effects Photothermal effects Photomechanical effects Photochemical effects Luminescence

       

) ( ) (      

R s Th F T

• P

P P P P P     

From the energy conservation law we obtain

 



s

P

 



T

P

 



• P

Incident power Transmitted power

 



F

P

Power used for fluorescence Power degraded into heat

 



Th

P

Scattered power

 



R

P

Reflected power

 

) ( ) (   

• T

P P T 

Transmittance

) ( log ) (   T A  

Absorbance

 

) ( ) (   

• F

P P F 

Fluorescence excitation spectrum

 

) ( ) (   

• R

P P R 

Reflectance

 

) ( ) (   

• Th

P P PT 

Photothermal spectrum

• 40
• 20

20 40

• 0.15
• 0.10
• 0.05

0.00 0.05 Mode-mismatched Mode-matched

TL signal

Sample position (cm)

Fo=-0.1, p=632 nm, e=750 nm, L=200 cm, D=0.001491 cm2/s, t=10 s, zp=0.2 cm for mode-matched scheme and zp=2000 cm for mode-mismatched scheme.

D Ampl. Sample Excitation laser M1 M2 F A Osc. L1 L2 L3 L4 Probe laser B z Ch

Marcano O. A. and N. Melikechi, App. Spectros. 61, 659-664 (2007).

• 20
• 10

10 20

• 0.06
• 0.03

0.00 0.03 Mode- mismatched Mode-matched TL signal Sample position (cm)

Experimental Z-scan of 1-cm cell containing distilled water measured under the mode-matched (open stars) and mode-mismatched (solid squares) schemes. p=632 nm, e=807 nm

700 800 900 1000 0.0 0.2 0.4

Mode-mismatched Mode-matched

Absorption (cm

• 1)

Wavelength (nm)

PTL spectra of distilled water measured using the mode-matched (large open stars) and mode-mismatched (large crossed circles) experimental configurations. Results of previous reports on water absorption of different authors have been included (small symbols).

Ultrasensitive spectroscopy of water

• R. A. Cruz, A. Marcano O., C. Jacinto, and T. Catunda, “Ultra-sensitive Thermal

Lens Spectroscopy of Water”, Opt. Lett. 34 (12), 1882-1884 (June 15, 2009).

High precision values of absorption of water in the 300-500 nm spectral region

700 800 900 1000 0.0 0.3 0.6

Comparison of TL spectrum with absorbance spec

• f distilled water measured by other authors

TL spectrum

Pope and Fry Palmer and Willians

Absorption coefficient (cm

• 1)

Wavelength (nm)

700 800 900 0.00 0.05 0.10 0.15 Absorbance Wavelength (nm) Ethanol TL Cary absorbance measurement

NIR spectroscopy of Ethanol

700 750 800 850 900 950 0.0 0.1 0.2 0.3 Absorbance Wavelength (nm) PTL Methanol cell 1 mm Cary absorbance

NIR of Methanol

Nd:YAG OPO He- Ne M1 M2 D1 D2 D3 BS1 L1 Sample BS2 F1 M3 L2 D4

Laser based PTL, absorbance ,and fluorescence excitation spectrophotometer.

• J. Hung, A. Marcano O., J. Castillo, J. Gonzalez, V. Piscitelli, A. Reyes and A. Fernandez,

“Thermal lensing and absorbance spectra of a fluorescent dye”, Chem. Phys. Lett. 386, 206-210 (2004).

A L3 F2

Figure 2. Hung et al.

450 475 500 525 550 575 0,00 0,01 0,02 0,03

Absolute values F(e) 1-T(e) ATh(e) Wavelength (nm)

. Absorbance (crossed circles), fluorescence excitation (crossed stars) and TL spectra (solid

triangles) of a 5 10-6 M ethanol solution of Rhodamine 6G. The solid line is the absorbance spectrum of the same sample obtained using a spectrophotometer.

Figure 3. Hung et al.

475 500 525 550 0,000 0,006 0,012

F(e) 1-T(e) ATh(e) Absolute values Wavelength (nm)

Absorbance (crossed circles), fluorescence excitation (crossed stars) and TL spectra (solid triangles) of the same sample of previous slide after adding of the quencher (KI).

475 500 525 550 0,0 0,5 1,0

With quencher No quencher

Fluorescence Quantum Yield Wavelength (nm) Fluorescence quantum yield spectrum of the 5 10-6 M ethanol solution of Rhodamine 6G in presence of high fluorescence and in the presence of fluorescence quenching.

He-Ne L1 L2 M1 S M2 D Ch Xe Lamp A M3 IFS L3 L4 B

White light photothermal lens spectrophotometer

PTL spectrum of a non-fluorescent dye

400 500 600 700 50 100 150 Wavelength (nm)

Molar extinction coefficient (mM

• 1 cm
• 1)

0.0 0.4 0.8

ATL() PTL spectrum of 0.125 mM solution of Malachite green in ethanol. There is coincidence with the absorbance spectrum.

• A. Marcano O., J. Ojeda and N. Melikechi, “Absorption spectra of dye solutions measured using a white-

light thermal lens spectrophotometer”, Appl. Spectros. 60 (5), 560-563 (2006).

PTL of a fluorescent dye

400 450 500 550 600 50 100 Wavelength (nm)

Molar extinction coefficient (mM

• 1 cm
• 1)

0.0 0.1 0.2 0.3

ATL()

PTL and absorbance spectra of a 50 mM solution of R6G in ethanol. Because of fluorescence both spectra are different. This property of PTL spectroscopy can be used for measuring the quantum yield of fluorescence

Quantum yield of fluorescence

450 450 500 500 550 550 600 600 0.0 0.5 1.0 W

F

Wavelen elengt gth (nm nm)

     

) L ) ( exp( 1 / ) ( A 1

TL F F

        W

L ) ( ) ( ATL

TL

  

PTL absorbance absorbance

F



Average wavelength

• f fluorescence

400 500 600 700 0.0 5.0x10

4

1.0x10

5

1.5x10

5

Extinction (cm

• 1/M)

Wavelength (nm)

Malachite Green Oxalate

400 500 600 700 0.0 5.0x10

4

1.0x10

5

1.5x10

5

Extinction (cm

• 1/M)

Wavelength (nm)

Malachite Green Oxalate

a b

a- PTL and extinction spectra of Malachite Green Oxalate with no polystyrene microbeads added; b- PTL and extinction spectra of Malachite Green Oxalate containing polystyrene microbeads at concentration of 0.005% by weight. The standard deviation is estimated averaging over 5 different experiments.

PTL spectroscopy of scattering samples

• A. Marcano O., S. Alvarado, J. Meng, D. Caballero, E. Marin and R. Edziah, Applied Spectroscopy, 68 (6), 680-685, June
• 2014. DOI: 10.1366/13-07385.

a

500 600 700 0.0 0.5 1.0 Normalized PTL Signal Wavelength (nm) Methylene Blue

b

400 500 600 700 0.0 0.5 1.0

0.0017 %

Normalized Extinction Wavelength (nm) Methylene Blue

0  0.005 %

a - Normalized PTL spectra of Nile Blue with polystyrene microbeads added at concentration of 0 (crossed circles), 0.0017% (stars) and 0.005% (crossed squares) by weight; b- Normalized extinction spectra of Nile Blue containing polystyrene microbeads at concentration of 0, 0.0017% and 0.005% by weight as indicated. The standard deviation is estimated averaging over 5 different experiments.

400 500 600 700 0.0 0.5 1.0 Scattering Quantum Yield Wavelength (nm) Malachite Green 500 600 700 0.0 0.5 1.0 Scattering Quantum Yield Wavelength (nm) Methylene Blue

a b

a- Scattering quantum yield of the Malachite Green Oxalate sample with added polystyrene microparticles at 0.005 % concentration by weight; b- Scattering quantum yield of the Nyle Blue sample with added polystyrene microparticles at 0.005 % by weight. The standard deviation is estimated averaging over 5 different experiments.

400 500 600 700 10

9

10

10

10

11

Extinction coefficient (cm-1/M) Wavelength (nm)

Au nanoparticles

Extinction (solid line) and PTL (crossed circles) spectra of a solution of 50-nm diameter gold nanoparticles at concentration of 1 mg/mL. The standard deviation is estimated averaging over 5 different experiments.

400 500 600 700 0.0 0.5 1.0 Scattering Quantum Yield Wavelength (nm) Malachite Green 500 600 700 0.0 0.5 1.0 Scattering Quantum Yield Wavelength (nm) Methylene Blue

a b

a- Scattering quantum yield of the Malachite Green Oxalate sample with added polystyrene microparticles at 0.005 % concentration by weight; b- Scattering quantum yield of the Nyle Blue sample with added polystyrene microparticles at 0.005 % by weight. The standard deviation is estimated averaging over 5 different experiments.

400 500 600 700 0.01 0.1 1 10 Extinction coefficient (A.U.) Wavelength (nm) Blood

a b

400 500 600 700 0.0 0.5 1.0 Scattering Quantum Yield Wavelength (nm) Blood

a- Extinction (solid line) and PTL (crossed circles) spectra of a blood sample; b- Scattering quantum yield of the same blood sample. The standard deviation is estimated averaging over 5 different experiments.

Photothermal mirror effect

Nanometric bump Excitation light Reflected light

Xe lamp He-Ne Co Ch D1 S F L1 L2 B M1 M2 D2 A Pre-Ampl Osc.

White-light photothermal mirror spectrophotometer

The signal is defined as

• T

T T S   ) ( ) (  

T() is the transmission through the aperture of the probe light in the presence of the pump beam. To is the transmission through the aperture of the probe light in the absence of the pump beam.

) ( ) ( ) (        P K S

A model based on the simultaneous resolution of the thermo- elastic deformation of the surface and thermal diffusivity equation predicts that

) ( 

is the fraction of absorbed energy used to generate heat

) ( P

is the power of the pump light

K

is a proportionality coefficient that does not depend on 

) ( 

PTM spectrum

PTM (black crossed squares) and absorbance (red crossed circles) of a glass plate

400 500 600 700 3 6 Absorbance Absorbance and PTM Wavelength (nm) Small dark glass plate 2 mm PTM

400 500 600 700 0.0 0.2 0.4 0.6 0.8 PTM Wavelength (nm) Ag plate no plasma

PTM spectra of a film made using the deposits from a silver nanoparticle solution

400 500 600 700 2 4 6 8 PTM Signal (Arb. Units) Wavelength (nm) Dy2TiO5

PTM spectrum of the dysprosium titanate sample

Conclusions Photothermal spectroscopy (PT) is a new spectroscopic method that measures the ability of matter to produce heat following the absorption

• f light.

PT spectra and absorbance spectra coincide for samples with 100 % thermal yield.

Advantages

• High sensitive
• Universality (any sample, any spectral

region).

• Scattering and fluorescence free
• Only visible sensor technology required (no

IR or UV sensors needed)

• Remote sample analysis possible
• Traditional and modern light source

technology can be adapted.

• Low cost.

Light Sources for PT Spectroscopy

Arc lamps

http://zeiss-campus.magnet.fsu.edu/print/lightsources/xenonarc-print.htm

High Intensity Tunable Light Source 22K$ www.newport.com

White Leds 10$ on ebay

The Argon laser

NIR lasers (MIRA 900) Fs and CW modes 700-1050 nm Vantage tunable diode

Spectra Physics Velocity™ Widely Tunable Lasers

Tunable diodes

Laser supercontinuum – good option for phototohermal spectroscopy

http://www.nktphotonics.com/