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Label-free imaging of neurotransmitters in live brain tissue by multi-photon ultraviolet microscopy. Neuronal Signal 2018; 2:NS20180132. [PMID: 32714595 PMCID: PMC7373235 DOI: 10.1042/ns20180132] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/20/2018] [Accepted: 10/29/2018] [Indexed: 12/20/2022] Open
Abstract
Visualizing small biomolecules in living cells remains a difficult challenge. Neurotransmitters provide one of the most frustrating examples of this difficulty, as our understanding of signaling in the brain critically depends on our ability to follow the neurotransmitter traffic. Last two decades have seen considerable progress in probing some of the neurotransmitters, e.g. by using false neurotransmitter mimics, chemical labeling techniques, or direct fluorescence imaging. Direct imaging harnesses the weak UV fluorescence of monoamines, which are some of the most important neurotransmitters controlling mood, memory, appetite, and learning. Here we describe the progress in imaging of these molecules using the least toxic direct excitation route found so far, namely multi-photon (MP) imaging. MP imaging of serotonin, and more recently that of dopamine, has allowed researchers to determine the location of the vesicles, follow their intracellular dynamics, probe their content, and monitor their release. Recent developments have even allowed ratiometric quantitation of the vesicular content. This review shows that MP ultraviolet (MP-UV) microscopy is an effective but underutilized method for imaging monoamine neurotransmitters in neurones and brain tissue.
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Lee S, Lee JH, Wang T, Jang WH, Yoon Y, Kim B, Jun YW, Kim MJ, Kim KH. Three-photon tissue imaging using moxifloxacin. Sci Rep 2018; 8:9415. [PMID: 29925864 PMCID: PMC6010410 DOI: 10.1038/s41598-018-27371-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 05/30/2018] [Indexed: 12/13/2022] Open
Abstract
Moxifloxacin is an antibiotic used in clinics and has recently been used as a clinically compatible cell-labeling agent for two-photon (2P) imaging. Although 2P imaging with moxifloxacin labeling visualized cells inside tissues using enhanced fluorescence, the imaging depth was quite limited because of the relatively short excitation wavelength (<800 nm) used. In this study, the feasibility of three-photon (3P) excitation of moxifloxacin using a longer excitation wavelength and moxifloxacin-based 3P imaging were tested to increase the imaging depth. Moxifloxacin fluorescence via 3P excitation was detected at a >1000 nm excitation wavelength. After obtaining the excitation and emission spectra of moxifloxacin, moxifloxacin-based 3P imaging was applied to ex vivo mouse bladder and ex vivo mouse small intestine tissues and compared with moxifloxacin-based 2P imaging by switching the excitation wavelength of a Ti:sapphire oscillator between near 1030 and 780 nm. Both moxifloxacin-based 2P and 3P imaging visualized cellular structures in the tissues via moxifloxacin labeling, but the image contrast was better with 3P imaging than with 2P imaging at the same imaging depths. The imaging speed and imaging depth of moxifloxacin-based 3P imaging using a Ti:sapphire oscillator were limited by insufficient excitation power. Therefore, we constructed a new system for moxifloxacin-based 3P imaging using a high-energy Yb fiber laser at 1030 nm and used it for in vivo deep tissue imaging of a mouse small intestine. Moxifloxacin-based 3P imaging could be useful for clinical applications with enhanced imaging depth.
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Affiliation(s)
- Seunghun Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Jun Ho Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Taejun Wang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Won Hyuk Jang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Yeoreum Yoon
- Department of Mechanical Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Bumju Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Yong Woong Jun
- Department of Chemistry, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Myoung Joon Kim
- Department of Ophthalmology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
| | - Ki Hean Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea. .,Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea.
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Anzalone A, Chacko JV, Nishi RA, Dumont C, Smith D, Shea LD, Digman MA, Cummings BJ, Anderson AJ. Feasibility study on mouse live imaging after spinal cord injury and poly(lactide-co-glycolide) bridge implantation. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-6. [PMID: 29959835 PMCID: PMC8357334 DOI: 10.1117/1.jbo.23.6.065007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
Spinal cord injury (SCI) causes permanent paralysis below the damaged area. SCI is linked to neuronal death, demyelination, and limited ability of neuronal fibers to regenerate. Regeneration capacity is limited by the presence of many inhibitory factors in the spinal cord environment. The use of poly(lactide-co-glycolide) (PLG) bridges has demonstrated the ability to sustain long-term regeneration after SCI in a cervical hemisection mouse model. Critically, imaging of regenerating fibers and the myelination status of these neuronal filaments is a severe limitation to progress in SCI research. We used a transgenic mouse model that selectively expresses fluorescent reporters (eGFP) in the neuronal fibers of the spinal cord. We implanted a PLG bridge at C5 vertebra after hemisection and evaluated in live animals' neuronal fibers at the bridge interface and within the bridge 8 weeks postimplant. These in vivo observations were correlated with in situ evaluation 12 weeks postimplantation. We sectioned the spinal cords and performed fluorescent bioimaging on the sections to observe neuronal fibers going through the bridge. In parallel, to visualize myelination of regenerated axons, we exploited the characteristics of the third-harmonic generation arising from the myelin structure in these fixed sections.
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Affiliation(s)
- Andrea Anzalone
- University of California, Institute for Memory Impairments and Neurological Disorders, Irvine, California, United States
| | - Jenu V. Chacko
- University of California Irvine, Department of Biomedical Engineering, Irvine, California, United States
| | - Rebecca A. Nishi
- University of California, Institute for Memory Impairments and Neurological Disorders, Irvine, California, United States
- University of California, Sue and Bill Gross Stem Cell Research Center, Irvine, California, United States
| | - Courtney Dumont
- University of Michigan, Department of Chemical Engineering, Ann Arbor, Michigan, United States
- University of Michigan, Department of Biomedical Engineering, Ann Arbor, Michigan, United States
| | - Dominique Smith
- University of Michigan, Department of Chemical Engineering, Ann Arbor, Michigan, United States
- University of Michigan, Department of Biomedical Engineering, Ann Arbor, Michigan, United States
| | - Lonnie D. Shea
- University of Michigan, Department of Chemical Engineering, Ann Arbor, Michigan, United States
- University of Michigan, Department of Biomedical Engineering, Ann Arbor, Michigan, United States
| | - Michelle A. Digman
- University of California Irvine, Department of Biomedical Engineering, Irvine, California, United States
- University of California Irvine, Laboratory for Fluorescence Dynamics, Irvine, California, United States
| | - Brian J. Cummings
- University of California, Institute for Memory Impairments and Neurological Disorders, Irvine, California, United States
- University of California, Sue and Bill Gross Stem Cell Research Center, Irvine, California, United States
- University of California, Department of Physical Medicine and Rehabilitation, Irvine, California, United States
- University of California, Department of Anatomy and Neurobiology, Irvine, California, United States
| | - Aileen J. Anderson
- University of California, Institute for Memory Impairments and Neurological Disorders, Irvine, California, United States
- University of California, Sue and Bill Gross Stem Cell Research Center, Irvine, California, United States
- University of California, Department of Physical Medicine and Rehabilitation, Irvine, California, United States
- University of California, Department of Anatomy and Neurobiology, Irvine, California, United States
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Yamanaka M, Saito K, Smith NI, Arai Y, Uegaki K, Yonemaru Y, Mochizuki K, Kawata S, Nagai T, Fujita K. Visible-wavelength two-photon excitation microscopy for fluorescent protein imaging. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:101202. [PMID: 26238663 DOI: 10.1117/1.jbo.20.10.101202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 03/25/2015] [Indexed: 05/21/2023]
Abstract
The simultaneous observation of multiple fluorescent proteins (FPs) by optical microscopy is revealing mechanisms by which proteins and organelles control a variety of cellular functions. Here we show the use of visible-light based two-photon excitation for simultaneously imaging multiple FPs. We demonstrated that multiple fluorescent targets can be concurrently excited by the absorption of two photons from the visible wavelength range and can be applied in multicolor fluorescence imaging. The technique also allows simultaneous single-photon excitation to offer simultaneous excitation of FPs across the entire range of visible wavelengths from a single excitation source. The calculation of point spread functions shows that the visible-wavelength two-photon excitation provides the fundamental improvement of spatial resolution compared to conventional confocal microscopy.
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Affiliation(s)
- Masahito Yamanaka
- Osaka University, Department of Applied Physics, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kenta Saito
- Osaka University, The Institute of Scientific and Industrial Research, 8-1 Mihogaoka, Ibaraki, Osaka 565-0871, Japan
| | - Nicholas I Smith
- Osaka University, Immunology Frontier Research Center, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yoshiyuki Arai
- Osaka University, The Institute of Scientific and Industrial Research, 8-1 Mihogaoka, Ibaraki, Osaka 565-0871, Japan
| | - Kumiko Uegaki
- Osaka University, Department of Applied Physics, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yasuo Yonemaru
- Osaka University, Department of Applied Physics, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kentaro Mochizuki
- Osaka University, Department of Applied Physics, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Satoshi Kawata
- Osaka University, Department of Applied Physics, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takeharu Nagai
- Osaka University, The Institute of Scientific and Industrial Research, 8-1 Mihogaoka, Ibaraki, Osaka 565-0871, Japan
| | - Katsumasa Fujita
- Osaka University, Department of Applied Physics, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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Trägårdh J, Robb G, Amor R, Amos WB, Dempster J, McConnell G. Exploration of the two-photon excitation spectrum of fluorescent dyes at wavelengths below the range of the Ti:Sapphire laser. J Microsc 2015; 259:210-8. [PMID: 25946127 PMCID: PMC4700633 DOI: 10.1111/jmi.12255] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 03/20/2015] [Indexed: 11/28/2022]
Abstract
We have studied the wavelength dependence of the two-photon excitation efficiency for a number of common UV excitable fluorescent dyes; the nuclear stains DAPI, Hoechst and SYTOX Green, chitin- and cellulose-staining dye Calcofluor White and Alexa Fluor 350, in the visible and near-infrared wavelength range (540-800 nm). For several of the dyes, we observe a substantial increase in the fluorescence emission intensity for shorter excitation wavelengths than the 680 nm which is the shortest wavelength usually available for two-photon microscopy. We also find that although the rate of photo-bleaching increases at shorter wavelengths, it is still possible to acquire many images with higher fluorescence intensity. This is particularly useful for applications where the aim is to image the structure, rather than monitoring changes in emission intensity over extended periods of time. We measure the excitation spectrum when the dyes are used to stain biological specimens to get a more accurate representation of the spectrum of the dye in a cell environment as compared to solution-based measurements.
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Affiliation(s)
- J Trägårdh
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - G Robb
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - R Amor
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - W B Amos
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
- MRC Laboratory of Molecular Biology, Cambridge, U.K
| | - J Dempster
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - G McConnell
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
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Trägårdh J, Robb G, Gadalla KKE, Cobb S, Travis C, Oppo GL, McConnell G. Label-free imaging of thick tissue at 1550 nm using a femtosecond optical parametric generator. OPTICS LETTERS 2015; 40:3484-7. [PMID: 26258338 DOI: 10.1364/ol.40.003484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We have developed a simple wavelength-tunable optical parametric generator (OPG), emitting broadband ultrashort pulses with peak wavelengths at 1530-1790 nm, for nonlinear label-free microscopy. The OPG consists of a periodically poled lithium niobate crystal, pumped at 1064 nm by a ultrafast Yb:fiber laser with high pulse energy. We demonstrate that this OPG can be used for label-free imaging, by third-harmonic generation, of nuclei of brain cells and blood vessels in a >150 μm thick brain tissue section, with very little decay of intensity with imaging depth and no visible damage to the tissue at an incident average power of 15 mW.
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7
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Ware LA. Three photons are better than two. Biotechniques 2014; 57:237-9. [PMID: 25391912 DOI: 10.2144/000114225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Three-photon microscopy was suggested in the 1990s, but laser technology at the time was just not up to the challenge. Lauren Ware explores how recent technology advances are bringing three-photon microscopy back into focus.
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8
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Thomas G, van Voskuilen J, Gerritsen HC, Sterenborg HJCM. Advances and challenges in label-free nonlinear optical imaging using two-photon excitation fluorescence and second harmonic generation for cancer research. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 141:128-38. [PMID: 25463660 DOI: 10.1016/j.jphotobiol.2014.08.025] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 08/20/2014] [Accepted: 08/23/2014] [Indexed: 11/28/2022]
Abstract
Nonlinear optical imaging (NLOI) has emerged to be a promising tool for bio-medical imaging in recent times. Among the various applications of NLOI, its utility is the most significant in the field of pre-clinical and clinical cancer research. This review begins by briefly covering the core principles involved in NLOI, such as two-photon excitation fluorescence (TPEF) and second harmonic generation (SHG). Subsequently, there is a short description on the various cellular components that contribute to endogenous optical fluorescence. Later on the review deals with its main theme--the challenges faced during label-free NLO imaging in translational cancer research. While this review addresses the accomplishment of various label-free NLOI based studies in cancer diagnostics, it also touches upon the limitations of the mentioned studies. In addition, areas in cancer research that need to be further investigated by label-free NLOI are discussed in a latter segment. The review eventually concludes on the note that label-free NLOI has and will continue to contribute richly in translational cancer research, to eventually provide a very reliable, yet minimally invasive cancer diagnostic tool for the patient.
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Affiliation(s)
- Giju Thomas
- Department of Biomedical Engineering and Physics, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands; Centre for Optical Diagnostics and Therapy, Erasmus Medical Centre, Post Box 2040, 3000 CA, Rotterdam, the Netherlands.
| | - Johan van Voskuilen
- Department of Molecular Biophysics, Utrecht University, 3508 TA Utrecht, The Netherlands
| | - Hans C Gerritsen
- Department of Molecular Biophysics, Utrecht University, 3508 TA Utrecht, The Netherlands
| | - H J C M Sterenborg
- Department of Biomedical Engineering and Physics, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
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9
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Norris G, Gebril A, Ferro VA, McConnell G. Methanol immersion reduces spherical aberration of water dipping lenses at long wavelengths used in multi-photon laser scanning microscopy. BIOMEDICAL OPTICS EXPRESS 2012; 3:3314-3324. [PMID: 23243580 PMCID: PMC3521300 DOI: 10.1364/boe.3.003314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 11/16/2012] [Accepted: 11/19/2012] [Indexed: 06/01/2023]
Abstract
Dipping objectives were tested for multi-photon laser scanning microscopy, since their large working distances are advantageous for thick specimens and the absence of a coverslip facilitates examination of living material. Images of fluorescent bead specimens, particularly at wavelengths greater than 850 nm showed defects consistent with spherical aberration. Substituting methanol for water as the immersion medium surrounding the beads corrected these defects and produced an increase in fluorescence signal intensity. The same immersion method was applied to two representative biological samples of fixed tissue: mouse brain labeled with FITC for tubulin and mouse gut in which the Peyer's patches were labeled with Texas Red bilosomes. Tissue morphology was well preserved by methanol immersion of both tissues; the two-photon-excited fluorescence signal was six times higher than in water and the depth of penetration of useful imaging was doubled. No modification of the microscope was needed except the provision of a ring to retain a sufficient depth of methanol for imaging.
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Norris G, Amor R, Dempster J, Amos WB, McConnell G. Increased signals from short-wavelength-excited fluorescent molecules using sub-Ti:Sapphire wavelengths. J Microsc 2012; 248:200-7. [PMID: 23078118 PMCID: PMC3746106 DOI: 10.1111/j.1365-2818.2012.03663.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Accepted: 08/14/2012] [Indexed: 11/28/2022]
Abstract
We report the use of an all-solid-state ultrashort pulsed source specifically for two-photon microscopy at wavelengths shorter than those of the conventional Ti:Sapphire laser. Our approach involves sum-frequency mixing of the output from an optical parametric oscillator (λ= 1400-1640 nm) synchronously pumped by a Yb-doped fibre laser (λ= 1064 nm), with the residual pump radiation. This generated an fs-pulsed output tunable in the red spectral region (λ= 620-636 nm, ~150 mW, 405 fs, 80 MHz, M(2) ~ 1.3). We demonstrate the performance of our ultrashort pulsed system using fluorescently labelled and autofluorescent tissue, and compare with conventional Ti:Sapphire excitation. We observe a more than 3-fold increase in fluorescence signal intensity using our visible laser source in comparison with the Ti:Sapphire laser for two-photon excitation at equal illumination peak powers of 1.16 kW or less.
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Affiliation(s)
- G Norris
- Centre for Biophotonics, SIPBS, University of Strathclyde, Glasgow, UK
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Amor R, Norris G, Dempster J, Amos WB, McConnell G. A compact instrument for adjusting laser beams to be accurately coincident and coaxial and its use in biomedical imaging using wave-mixed laser sources. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:083705. [PMID: 22938301 DOI: 10.1063/1.4745373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Biomedical imaging applications that involve nonlinear optical processes such as sum-frequency generation (SFG) and four-wave mixing require that the pulses are synchronized in time and the beams are coaxial to better than 400 μrad. For this reason, folding mirrors are normally used to extend the beam path over a few meters so that detectors can be put into the beams to check their overlap at the start of a long path and also at the end of it. We have made a portable instrument with a footprint of only 22 cm × 11 cm × 16 cm that uses a short focal length lens and a telephoto combination for viewing the near-field and far-field simultaneously. Our instrument is simple to build and use, and we show its application in coherent anti-Stokes Raman scattering microscopy and SFG-based two-photon fluorescence microscopy.
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Affiliation(s)
- R Amor
- Centre for Biophotonics, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, United Kingdom.
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