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An Analog Filter Approach to Frequency Domain Fluorescence Spectroscopy.

Trainham R, O'Neill M, McKenna IJ - J Fluoresc (2015)

Bottom Line: The rate equations found in frequency domain fluorescence spectroscopy are the same as those found in electronics under analog filter theory.The techniques described here can be used to separate signals from fast and slow fluorophores emitting into the same spectral band, and data collection can be greatly accelerated by means of a frequency comb driver waveform and appropriate signal processing of the response.The simplification of the analysis mathematics, and the ability to model the entire detection chain, make it possible to develop more compact instruments for remote sensing applications.

View Article: PubMed Central - PubMed

Affiliation: Special Technologies Laboratory, National Security Technologies, LLC, 5520 Ekwill Street, Santa Barbara, CA, 93111, USA. trainhcp@nv.doe.gov.

ABSTRACT
The rate equations found in frequency domain fluorescence spectroscopy are the same as those found in electronics under analog filter theory. Laplace transform methods are a natural way to solve the equations, and the methods can provide solutions for arbitrary excitation functions. The fluorescence terms can be modelled as circuit components and cascaded with drive and detection electronics to produce a global transfer function. Electronics design tools such as SPICE can be used to model fluorescence problems. In applications, such as remote sensing, where detection electronics are operated at high gain and limited bandwidth, a global modelling of the entire system is important, since the filter terms of the drive and detection electronics affect the measured response of the fluorescence signals. The techniques described here can be used to separate signals from fast and slow fluorophores emitting into the same spectral band, and data collection can be greatly accelerated by means of a frequency comb driver waveform and appropriate signal processing of the response. The simplification of the analysis mathematics, and the ability to model the entire detection chain, make it possible to develop more compact instruments for remote sensing applications.

No MeSH data available.


This family of curves for mixtures of fast and slow fluorescence lifetimes was generated from a uranyl fluoride sample and coumarin dye excited by a 365 nm laser diode array, and the fluorescence light collected by a photodiode and measured with a lock-in detector
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Fig6: This family of curves for mixtures of fast and slow fluorescence lifetimes was generated from a uranyl fluoride sample and coumarin dye excited by a 365 nm laser diode array, and the fluorescence light collected by a photodiode and measured with a lock-in detector

Mentions: The behavior of the response phase shift with drive frequency is the most dramatic effect of multiple decay lifetimes. FigureĀ 6 shows a family of experimental curves for known mixtures of fast and slow fluorophores. The two samples used were coumarin dye, with a picosecond lifetime, and uranyl fluoride, with a half millisecond lifetime. Varying the mixture of the two samples via fk reveals that the fast lifetime fluorescence partially masks the full phase shift of the slow component. This is because the amplitude of the slow component diminishes as it is driven faster than its natural decay rate. Its fluorescence becomes a DC light level. The fast component, however, still oscillates in phase with the driver at full amplitude, so its signal tends to dominate the response as the drive frequency is increased. These experimental results were collected using a Nichia NCSU033AE LED array to provide excitation light at 365 nm. The signal waveform to drive the LED array was generated by an Agilent 33250A function generator and boosted by a Tegam 2348 power amplifier. The fluorescence light was filtered by an Andover 550FS40-50 bandpass filter to remove the driver light, and the photodiode detector was a Thorlab PDA36A set at 0 dB gain. The signal was measured by an EG&G Signal Recovery 7260 lock-in detector.Fig. 6


An Analog Filter Approach to Frequency Domain Fluorescence Spectroscopy.

Trainham R, O'Neill M, McKenna IJ - J Fluoresc (2015)

This family of curves for mixtures of fast and slow fluorescence lifetimes was generated from a uranyl fluoride sample and coumarin dye excited by a 365 nm laser diode array, and the fluorescence light collected by a photodiode and measured with a lock-in detector
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4644193&req=5

Fig6: This family of curves for mixtures of fast and slow fluorescence lifetimes was generated from a uranyl fluoride sample and coumarin dye excited by a 365 nm laser diode array, and the fluorescence light collected by a photodiode and measured with a lock-in detector
Mentions: The behavior of the response phase shift with drive frequency is the most dramatic effect of multiple decay lifetimes. FigureĀ 6 shows a family of experimental curves for known mixtures of fast and slow fluorophores. The two samples used were coumarin dye, with a picosecond lifetime, and uranyl fluoride, with a half millisecond lifetime. Varying the mixture of the two samples via fk reveals that the fast lifetime fluorescence partially masks the full phase shift of the slow component. This is because the amplitude of the slow component diminishes as it is driven faster than its natural decay rate. Its fluorescence becomes a DC light level. The fast component, however, still oscillates in phase with the driver at full amplitude, so its signal tends to dominate the response as the drive frequency is increased. These experimental results were collected using a Nichia NCSU033AE LED array to provide excitation light at 365 nm. The signal waveform to drive the LED array was generated by an Agilent 33250A function generator and boosted by a Tegam 2348 power amplifier. The fluorescence light was filtered by an Andover 550FS40-50 bandpass filter to remove the driver light, and the photodiode detector was a Thorlab PDA36A set at 0 dB gain. The signal was measured by an EG&G Signal Recovery 7260 lock-in detector.Fig. 6

Bottom Line: The rate equations found in frequency domain fluorescence spectroscopy are the same as those found in electronics under analog filter theory.The techniques described here can be used to separate signals from fast and slow fluorophores emitting into the same spectral band, and data collection can be greatly accelerated by means of a frequency comb driver waveform and appropriate signal processing of the response.The simplification of the analysis mathematics, and the ability to model the entire detection chain, make it possible to develop more compact instruments for remote sensing applications.

View Article: PubMed Central - PubMed

Affiliation: Special Technologies Laboratory, National Security Technologies, LLC, 5520 Ekwill Street, Santa Barbara, CA, 93111, USA. trainhcp@nv.doe.gov.

ABSTRACT
The rate equations found in frequency domain fluorescence spectroscopy are the same as those found in electronics under analog filter theory. Laplace transform methods are a natural way to solve the equations, and the methods can provide solutions for arbitrary excitation functions. The fluorescence terms can be modelled as circuit components and cascaded with drive and detection electronics to produce a global transfer function. Electronics design tools such as SPICE can be used to model fluorescence problems. In applications, such as remote sensing, where detection electronics are operated at high gain and limited bandwidth, a global modelling of the entire system is important, since the filter terms of the drive and detection electronics affect the measured response of the fluorescence signals. The techniques described here can be used to separate signals from fast and slow fluorophores emitting into the same spectral band, and data collection can be greatly accelerated by means of a frequency comb driver waveform and appropriate signal processing of the response. The simplification of the analysis mathematics, and the ability to model the entire detection chain, make it possible to develop more compact instruments for remote sensing applications.

No MeSH data available.