Kerr gate microscope

IV. Non-scanning Picosecond Fluorescence Kerr Gate Microscope.63... 

IV. NON-SCANNING PICOSECOND FLUORESCENCE KERR GATE MICROSCOPE... 

A. Apparatus of the Non-Scanning Picosecond Fluorescence Kerr Gate Microscope... 

A schematic diagram of the non-scanning picosecond fluorescence Kerr gate microscope is depicted in Figure 3.9a. A femtosecond Ti sapphire laser with regenerative amplifier provided femtosecond pulses (800 nm, 1 mJ, 110 fs) at a... 

FIGURE 3.9 Schematic diagram of the non-scanning picosecond fluorescence Kerr-gate microscope, (a) The microscope part, and (b) the Kerr gate part. (From Fujino, T., Fujima, T., and Tahara, T., Appl. Phys. Lett., 87 131105-131107, 2005. Used with permission.)... 

Fujino, T, Fujima, T, and Tahara, T. 2005. Picosecond Time-Resolved Imaging by Nonscaiming Fluorescence Kerr Gate Microscope. Appl. Phys. Lett. 87 131105. 

Figure 7.2 Optical block diagram of the wide field Kerr-gated microscope. Note the position of the sample (S), the sequence of three matched Cassegrain objectives (COi, CO2 and CO3), polarizers (Pi and P2), the Kerr medium (K) and blocking filters (F). A prism spectrometer (PR) can be inserted into the path of the gated light allowing monitoring of the collective spectral dynamics of objects within the field of view.

Switching from the imaging to the speetrally resolved mode of the Kerr-gated microscope reveals the time dependent emission spectrum of the nanobelts (Figure 7.5). In this case, for the sake of simplieity we placed only two nanobelts in the view of the microseope. The lumineseence intensity shown at the top... 

Certain chromophore systems are intrinsically predisposed for ultrafast single molecule microscopy. Among these, emitters coupled to metal surfaces stand out as exceptionally well-suited subjects. Numerous observations of substantial radiative rate enhancement at the surface or in the vicinity of the surface of a metal were reported. Radiative rate enhancements as large as 10 have been predicted for molecular fluorophores and for semiconductor quantum dots coupled to optimized nanoantennae.Such accelerated emission rates put these systems well within the reach of the emerging femtosecond microscopy techniques. As a result, we decided to apply the Kerr-gated microscope to study of fluorescence dynamics of individual core-shell quantum dots in contact with smooth and nanostructured metal surfaces. 

Figure 7.1 Time domains accessible to the wide field Kerr-gated fluorescence microscope and to confocal fluorescence microscopes relying on time-correlated-single photon-counting (TCSPC).

Figure 7.3 Light collecting objective and the Kerr-gate assembly of the second generation Rutgers microscope. The only non-reflective components are the nanowire polarizers and the 0.5. mm thick fused silica plate serving as the Kerr medium.

Since a molecule or a quantum dot can emit no more than one photon per excitation, the optimum source for ultrafast fluorescence microscopy has a high repetition rate (10 -10 Hz) and a pulse energy sufficient to pump an excitation NOPA (noncollinear optical parametric amplifier) and to drive the Kerr or up-conversion gate. The current configuration of the Rutgers microscope relies on a cryogenically cooled Ti sapphire regenerative amplifier which produces 50 gJ... 

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