Fourier and Confocal Microscopy

Fourier and 

Confocal Microscopy 

Fourier Microscopy (Back-focal plane Imaging)


Fourier microscope for the investigation of the directional scattering and directional emission of surfaces and nanostructures. Fourier microscopy is based on imaging the back-focal plane of an objective lens that collects the scattered or emitted light from a sample. This back-focal plane contains information about the scattered/emitted light intensity in defined directions. Fourier microscopy has been used for imaging the directional emission of fluorescent beads, dye-molecules coupled to plasmonic gratings, metamaterials, surface plasmon polariton waveguides, quantum dots coupled to plasmonic antennas or single plasmonic/dielectric nanowires.



Specifications:


        • Excitation wavelength range: 300 nm – 1000 nm
        • Equipped with high numerical aperture objective lenses (NA 0.95, dry) and (NA 1.4, oil-immersed) to access broad angular distributions
        • Integrated with electrical probes for electroluminescence measurements
        • Possibility of polarimetry and extraction of Stoke’s parameters


Examples:

(Left) Angular emission pattern of a single semiconductor (InP) nanowire shown in the scanning electron microscope image. (Middle and right) Angular emission patterns of a luminescent layer of dye molecules on top of two different arrays of metallic nanoparticles.

Confocal and Fluorescence Life-Time Imaging Microscopy


Confocal microscope in combination with a diffraction limited laser scanning head and sensitive detectors to perform micro-photoluminescence (micro-PL) and fluorescence life-time imaging measurements (FLIM). The excitation spot can be fixed while the diffraction limited detection spot can be scanned around the excitation, which allows the measurement of exciton, charge and/or photon transport.



Specifications:

          • Spatial resolution: diffraction-limited (approx. 400 nm)
          • Time-resolution for FLIM: 100 ps
          • Possibility of large area scanning (80 μm2 at 100x magnification)
          • Conventional/glass-corrected objectives for optimum imaging
          • Excitation wavelength range: 400 – 800 nm
          • Detection wavelength range: 400 – 1000 nm

Examples:

(Left) Scanning electron microscope image of a array of aluminum nanoparticles covered by layer of organic fluorophores. (Right) Corresponding fluorescent life-time image obtained by the confocal microscope. Scale bares are 0.5 mm.

(i) Reflection image of a WS2 sample with regions containing a single atomic layer (Dashed lines). (ii) Photoluminescence images of the monolayers in the WS2 sample. (iii) Fluorescnce life-time image of the WS2 monolayers. (iv) The average excited-state life-time of the monolayers. Scale bares are 5 mm.