scholarly journals Advances in high-repetition-rate ultrashort gigawatt laser systems for time-resolved spectroscopy

1992 ◽  
Author(s):  
Louis F. DiMauro
Keyword(s):  
Repetition Rate ◽  
High Repetition Rate ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
High Repetition ◽  
Laser Systems

scholarly journals Improving Signal and Photobleaching Characteristics of Temporal Focusing Microscopy with the Increase in Pulse Repetition Rate

2019 ◽  
Vol 2 (3) ◽  
pp. 65
Author(s):  
Viktoras Lisicovas ◽  
Bala Murali Krishna Mariserla ◽  
Chakradhar Sahoo ◽  
Reuben T. Harding ◽  
Michael K. L. Man ◽  
...  
Keyword(s):  
Pulse Energy ◽  
Repetition Rate ◽  
Signal Intensity ◽  
High Repetition Rate ◽  
High Peak Power ◽  
High Pulse Energy ◽  
Two Photon ◽  
High Repetition ◽  
Laser Systems ◽  
High Pulse

Wide-field temporal focused (WF-TeFo) two-photon microscopy allows for the simultaneous imaging of a large planar area, with a potential order of magnitude enhancement in the speed of volumetric imaging. To date, low repetition rate laser sources with over half a millijoule per pulse have been required in order to provide the high peak power densities for effective two-photon excitation over the large area. However, this configuration suffers from reduced signal intensity due to the low repetition rate, saturation effects due to increased excitation fluences, as well as faster photobleaching of the fluorescence probe. In contrast, with the recent advent of high repetition rate, high pulse energy laser systems could potentially provide the advantages of high repetition rate systems that are seen in traditional two-photon microscopes, while minimizing the negatives of high fluences in WF-TeFo setups to date. Here, we use a 100 microjoule/high repetition rate (50–100 kHz) laser system to investigate the performance of a WF-TeFo two-photon microscope. While using micro-beads as a sample, we demonstrate a proportionate increase in signal intensity with repetition rate, at no added cost in photobleaching. By decreasing pulse intensity, via a corresponding increase in repetition rate to maintain fluorescence signal intensity, we find that the photobleaching rate is reduced by ~98.4%. We then image live C. elegans at a high repetition rate for 25 min. as a proof-of-principle. Lastly, we identify the steady state temperature increase as the limiting process in further increasing the repetition rate, and we estimate that repetition rate in the range between 0.5 and 5 MHz is ideal for live imaging with a simple theoretical model. With new generation low-cost fiber laser systems offering high pulse energy/high repetition rates in what is essentially a turn-key solution, we anticipate increased adoption of this microscopy technique by the neuroscience community.

Fluorescence Decay Measurements via High Repetition Rate Gated Photon Counting

1980 ◽  
Vol 34 (2) ◽  
pp. 185-189 ◽  
Author(s):  
T. L. Gustafson ◽  
Fred E. Lytle
Keyword(s):  
Acridine Orange ◽  
Repetition Rate ◽  
Photon Counting ◽  
Fluorescence Decay ◽  
High Repetition Rate ◽  
Time Resolved ◽  
High Repetition ◽  
Ion Laser ◽  
Laser Sources ◽  
Time Resolved Measurements

Current methods for time-resolved measurements with photon counting detection are not able to take advantage adequately of the high repetition rates available from most pulsed ion laser sources. A technique is described which allows high repetition rate gating of fluorescence decays with photon counting detection. Fluorescence decay measurements of acridine orange (τ = 4.4 ns), rubrene (τ = 16.5 ns) and tris(bipyridine)ruthenium(II) dichloride (τ = 760 ns) are obtained at repetition rates as high as 2.7 MHz. The utility of this technique for analog measurements is also demonstrated.

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