title: Fast wide-field photothermal and quantitative phase cell imaging with optical lock-in detection.
abstract: We present a fast, wide-field holography system for detecting photothermally excited gold nanospheres with combined quantitative phase imaging. An interferometric photothermal optical lock-in approach (POLI) is shown to improve SNR for detecting nanoparticles (NPs) on multiple substrates, including a monolayer of NPs on a silanized coverslip, and NPs bound to live cells. Furthermore, the set up allowed for co-registered quantitative phase imaging (QPI) to be acquired in an off-axis holographic set-up. An SNR of 103 was obtained for NP-tagging of epidermal growth factor receptor (EGFR) in live cells with a 3 second acquisition, while an SNR of 47 was seen for 20 ms acquisition. An analysis of improvements in SNR due to averaging multiple frames is presented, which suggest that residual photothermal signal can be a limiting factor. The combination of techniques allows for high resolution imaging of cell structure via QPI with the ability to identify receptor expression via POLI.
authors.affiliation: Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA ; contributed equally.
authors.forename: Will J
authors.initials: WJ
authors.lastname: Eldridge
authors.affiliation: Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA ; contributed equally ; meiria1@gmail.com.
authors.forename: Amihai
authors.initials: A
authors.lastname: Meiri
authors.affiliation: Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA.
authors.forename: Adi
authors.initials: A
authors.lastname: Sheinfeld
authors.affiliation: Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Rinehart
authors.affiliation: Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Wax
keywords: (120.3180) Interferometry; (160.4236) Nanomaterials; (170.1650) Coherence imaging