Two-photon Bessel beam scanning microscope for neural activities (Conference Presentation)

2020 ◽  
Author(s):  
Dongli Xu ◽  
Leilei Peng ◽  
Jun Ding
Keyword(s):  
Bessel Beam ◽  
Scanning Microscope ◽  
Beam Scanning ◽  
Two Photon ◽  
Neural Activities

Nondegenerate two-photon absorption properties of a newly synthesized carbazole derivative

2017 ◽  
Vol 5 (2) ◽  
pp. 470-475 ◽  
Author(s):  
Shu Chen ◽  
Yong-Chao Zheng ◽  
Mei-Ling Zheng ◽  
Xian-Zi Dong ◽  
Feng Jin ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Photon Absorption ◽  
Scanning Microscope ◽  
Absorption Properties ◽  
Carbazole Derivative ◽  
Laser Scanning Microscope ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Potential Use

Nondegenerate two-photon absorption of a newly carbazole derivative is reported, demonstrating its potential use in a two-color two-photon laser scanning microscope.

Compact two-photon laser-scanning microscope made from minimally modified commercial components

2002 ◽  
Author(s):  
Vijay Iyer ◽  
Tycho Hoogland ◽  
Bradley E. Losavio ◽  
A. R. McQuiston ◽  
Peter Saggau
Keyword(s):  
Laser Scanning ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Two Photon

Axial Control of Two-Photon Polymerization With Femtosecond Bessel Beam

2017 ◽  
Author(s):  
Xiaoming Yu ◽  
Meng Zhang ◽  
Shuting Lei
Keyword(s):  
3D Printing ◽  
Bessel Beam ◽  
Average Diameter ◽  
Axial Direction ◽  
Polymerization Process ◽  
Layer By Layer ◽  
Light Modulator ◽  
Simultaneous Generation ◽  
Two Photon ◽  
Two Photon Polymerization

Stereolithography of three-dimensional, arbitrarily-shaped objects is achieved by successively curing photopolymer on multiple 2D planes and then stacking these 2D slices into 3D objects. Often as a bottleneck for speeding up the fabrication process, this layer-by-layer approach originates from the lack of axial control of photopolymerization. In this paper, we present a novel stereolithography technology with which two-photon polymerization can be dynamically controlled in the axial direction using Bessel beam generated from a spatial light modulator (SLM) and an axicon. First, we use unmodulated Bessel beam to fabricate micro-wires with an average diameter of 100 μm and a length exceeding 10 mm, resulting in an aspect ratio > 100:1. A study on the polymerization process shows that a fabrication speed of 2 mm/s can be achieved. Defect and deformation are observed, and the micro-wires consist of multiple narrow fibers which indicate the existence of the self-writing effect. A test case is presented to demonstrate fast 3D printing of a hollow tube within one second. Next, we modulate the Bessel beam with an SLM and demonstrate the simultaneous generation of multiple focal spots along the laser propagation direction. These spots can be dynamically controlled by loading an image sequence on the SLM. The theoretical foundation of this technology is outlined, and computer simulation is conducted to verify the experimental results. The presented technology extends current stereolithography into the third dimension, and has the potential to significantly increase 3D printing speed.

A custom confocal and two-photon digital laser scanning microscope

2000 ◽  
Vol 278 (6) ◽  
pp. H2150-H2156 ◽  
Author(s):  
W. Gil Wier ◽  
C. William Balke ◽  
Jeffrey A. Michael ◽  
Joseph R. H. Mauban
Keyword(s):  
Laser Scanning ◽  
Photon Counting ◽  
Objective Lens ◽  
Scanning Microscope ◽  
Fluorescence Detector ◽  
Laser Scanning Microscope ◽  
Ti:Sapphire Laser ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

We describe a custom one-photon (confocal) and two-photon all-digital (photon counting) laser scanning microscope. The confocal component uses two avalanche photodiodes (APDs) as the fluorescence detector to achieve high sensitivity and to overcome the limited photon counting rate of a single APD (∼5 MHz). The confocal component is approximately nine times more efficient than our commercial confocal microscope (fluorophore fluo 4). Switching from one-photon to two-photon excitation mode (Ti:sapphire laser) is accomplished by moving a single mirror beneath the objective lens. The pulse from the Ti:sapphire laser is 109 fs in duration at the specimen plane, and average power is ∼5 mW. Two-photon excited fluorescence is detected by a fast photomultiplier tube. With a ×63 1.4 NA oil-immersion objective, the resolution of the confocal system is 0.25 μm laterally and 0.52 μm axially. For the two-photon system, the corresponding values are 0.28 and 0.82 μm. The system is advantageous when excitation intensity must be limited, when fluorescence is low, or when thick, scattering specimens are being studied (with two-photon excitation).

Simultaneous imaging of multiple focal planes using a two-photon scanning microscope

2007 ◽  
Vol 32 (12) ◽  
pp. 1731 ◽  
Author(s):  
W. Amir ◽  
R. Carriles ◽  
E. E. Hoover ◽  
T. A. Planchon ◽  
C. G. Durfee ◽  
...  
Keyword(s):  
Scanning Microscope ◽  
Two Photon ◽  
Simultaneous Imaging

Bessel beam scanning without mechanical scanner

2015 ◽  
Author(s):  
M. E. Ventura ◽  
P. L. A. Hilario ◽  
G. Tapang ◽  
C. Saloma
Keyword(s):  
Bessel Beam ◽  
Beam Scanning

MRS-measured Glutamate versus GABA reflects excitatory versus inhibitory neural activities in awake mice

2020 ◽  
Author(s):  
Yuhei Takado ◽  
Hiroyuki Takuwa ◽  
Kazuaki Sampei ◽  
Takuya Urushihata ◽  
Manami Takahashi ◽  
...  
Keyword(s):  
Baseline Level ◽  
Dravet Syndrome ◽  
Inhibitory Neurons ◽  
Resonance Spectroscopy ◽  
Neural Firing ◽  
Wild Type ◽  
Calcium Signals ◽  
Two Photon ◽  
Neural Activities ◽  
Awake Condition

AbstractTo assess if magnetic resonance spectroscopy (MRS)-measured Glutamate (Glu) and GABA reflect excitatory and inhibitory neural activities, respectively, we conducted MRS measurements along with two-photon mesoscopic imaging of calcium signals in excitatory and inhibitory neurons of living, unanesthetized mice. For monitoring stimulus-driven activations of a brain region, MRS signals and mesoscopic neural activities were measured during two consecutive sessions of 15-min prolonged sensory stimulations. In the first session, putative excitatory neuronal activities were increased, while inhibitory neuronal activities remained at the baseline level. In the second half, while excitatory neuronal activities remained elevated, inhibitory neuronal activities were significantly enhanced. We also assessed regional neurochemical and functional statuses related to spontaneous neural firing by measuring MRS signals and neuronal activities in a mouse model of Dravet syndrome under a resting condition. Mesoscopic assessments showed that activities of inhibitory neurons in the cortex were diminished relative to wild-type mice in contrast to spared activities of excitatory neurons. Consistent with these observations, the Dravet model exhibited lower concentrations of GABA than wild-type controls. Collectively, the current investigations demonstrate that the MRS-measured Glu and GABA can reflect spontaneous and stimulated activities of neurons producing and releasing these neurotransmitters in an awake condition.

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