title: Flexible digital signal processing architecture for narrowband and spread-spectrum lock-in detection in multiphoton microscopy and time-resolved spectroscopy.
abstract: The lock-in amplifier is a critical component in many different types of experiments, because of its ability to reduce spurious or environmental noise components by restricting detection to a single frequency and phase. One example application is pump-probe microscopy, a multiphoton technique that leverages excited-state dynamics for imaging contrast. With this application in mind, we present here the design and implementation of a high-speed lock-in amplifier on the field-programmable gate array (FPGA) coprocessor of a data acquisition board. The most important advantage is the inherent ability to filter signals based on more complex modulation patterns. As an example, we use the flexibility of the FPGA approach to enable a novel pump-probe detection scheme based on spread-spectrum communications techniques.
authors.affiliation: Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Jesse W
authors.initials: JW
authors.lastname: Wilson
authors.affiliation: Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Jong Kang
authors.initials: JK
authors.lastname: Park
authors.affiliation: Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Warren S
authors.initials: WS
authors.lastname: Warren
authors.affiliation: Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Fischer
mesh_terms: D000818:Animals; D004867:Equipment Design; D021621:Imaging, Three-Dimensional / Q000295:instrumentation; D008543:Melanins / Q000737:chemistry; D008810:Mice, Inbred C57BL; D008853:Microscopy / Q000295:instrumentation* / Q000379:methods; D061848:Optical Imaging / Q000295:instrumentation* / Q000379:methods; D011166:Porphyrins / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D059629:Signal-To-Noise Ratio; D012867:Skin / Q000737:chemistry; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods
chemical_list: D008543:Melanins; D011166:Porphyrins; D012235:Rhodamines; C026188:rhodamine 6G
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