Photothermal Spectroscopy Lecture 2 - Applications Aristides - PowerPoint PPT Presentation

Winter College on Optics Photothermal Spectroscopy Lecture 2 - Applications Aristides Marcano Olaizola (PhD) Research Professor Department of Chemistry Delaware State University, US 1

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 one type of effect upon interaction with light Scattered light Transmitted light Incident light Absorption of light Photoacoustic effects Photothermal effects Reflected light Photomechanical effects Photochemical effects Luminescence

From the energy conservation law we obtain                    ( ) ( ) P P P P P P o T F Th s R    P Incident power o    Transmitted power P T    Power used for fluorescence P F    P Power degraded into heat Th    P Scattered power s    P Reflected power R

   P   T ( ) T Transmittance  ( ) P o Absorbance     ( ) log ( ) A T    P   Reflectance R ( ) R  ( ) P o    Fluorescence excitation P   F ( ) F  spectrum ( ) P   o  P   Th ( ) PT Photothermal spectrum  ( ) P o

0.05 Mode-matched TL signal 0.00 -0.05 -0.10 Mode-mismatched -0.15 -40 -20 0 20 40 Sample position (cm) F o =-0.1,  p =632 nm,  e =750 nm, L=200 cm, D=0.001491 cm 2 /s, t=10 s, z p =0.2 cm for mode-matched scheme and z p =2000 cm for mode-mismatched scheme.

Excitation laser Probe laser Ampl. Osc. L1 D L 2 A Ch L 3 Sample F L 4 M 2 M 1 B z Marcano O. A. and N. Melikechi, App. Spectros. 61 , 659-664 (2007).

Mode-matched 0.03 TL signal 0.00 Mode- -0.03  p =632 nm,  e =807 nm mismatched -0.06 -20 -10 0 10 20 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.

-1 ) 0.4 Mode-mismatched Absorption (cm 0.2 Mode-matched 0.0 700 800 900 1000 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 High precision values of absorption of water in the 300-500 nm spectral region 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).

-1 ) Absorption coefficient (cm Comparison of TL spectrum with absorbance spec 0.6 of distilled water measured by other authors Palmer and Willians 0.3 TL spectrum Pope and Fry 0.0 700 800 900 1000 Wavelength (nm)

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

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

M1 Nd:YAG OPO D2 D1 D3 L3 F1 L2 BS 1 M3 M2 BS 2 Sample L1 A F2 He- D4 Ne 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).

. 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. 1-T(  e ) 0,03 Absolute values 0,02 F(  e ) 0,01 A Th (  e ) 0,00 450 475 500 525 550 575 Wavelength (nm) Figure 2. Hung et al.

1-T(  e ) Absolute values 0,012 A Th (  e ) 0,006 F(  e ) 0,000 475 500 525 550 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). Figure 3. Hung et al.

1,0 Fluorescence Quantum Yield No quencher 0,5 With quencher 0,0 475 500 525 550 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.

White light photothermal lens spectrophotometer L 2 L 1 M 1 He-Ne IFS S L 3 L 4 B Xe Lamp M 2 A Ch D M 3

PTL spectrum of a non-fluorescent dye -1 ) -1 cm 150 0.8 Molar extinction coefficient (mM A TL (  ) 100 0.4 50 0 0.0 400 500 600 700 Wavelength (nm) 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 0.3 -1 ) -1 cm PTL and absorbance spectra of a 50 100 Molar extinction coefficient (mM mM solution of R6G in ethanol. 0.2 A TL (  ) 50 0.1 0 0.0 400 450 500 550 600 Wavelength (nm) 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       W         1 A ( ) / 1 exp( ( ) L ) F F TL 1.0 A TL ( )  TL F PTL absorbance W 0.5 ( ) L   absorbance 0.0 450 450 500 500 550 550 600 600  Average wavelength Wavelen elengt gth (nm nm) F of fluorescence

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. 5 5 1.5x10 a b 1.5x10 Malachite Green Oxalate Malachite Green Oxalate -1 /M) -1 /M) 5 5 Extinction (cm Extinction (cm 1.0x10 1.0x10 4 4 5.0x10 5.0x10 0.0 0.0 400 500 600 700 400 500 600 700 Wavelength (nm) Wavelength (nm) 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.

a b 1.0 1.0 Normalized PTL Signal Normalized Extinction Methylene Blue Methylene Blue 0.5 0.005 % 0.5 0.0017 % 0  0.0 0.0 400 500 600 700 500 600 700 Wavelength (nm) Wavelength (nm) 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.

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

Extinction coefficient (cm -1 /M) Au nanoparticles 11 10 10 10 9 10 400 500 600 700 Wavelength (nm) 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.

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

a b 10 Extinction coefficient (A.U.) Blood Scattering Quantum Yield Blood 1.0 1 0.5 0.1 0.0 0.01 400 500 600 700 400 500 600 700 Wavelength (nm) Wavelength (nm) 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 Excitation light Reflected light Nanometric bump

White-light photothermal mirror spectrophotometer M 1 Co He-Ne Ch L 1 L 2 B S Xe lamp F A D 2 M 2 D 1 Osc. Pre-Ampl