Superresolution microscopes

Until the advent of superresolution microscopes the only way to observe the minute world was based on the common Fourier-type microscopes. The maximum theoretical resolution limit for these apparatuses was established by Abbe, applying the Rayleigh-Fourier diffraction resolution rule [28]. The basic principle underlying the operational working of these ordinary microscopes is, in the eyes of Niels Bohr, a textbook example of Heisenberg uncertainty relations. 

Figure 29. Detection region of the two microscopes (a) usual Fourier microscope (b) superresolution microscope.

The superresolution microscope, in essence, just like the common microscope, is no more than a device for measurement of position, for the mapping of material points. Essentially both types work in the following way. The point forming the object are illuminated, generating diffused light that is eventually captured by the microscope. In this conceptual analysis, the microscope must be treated like a blackbox, since there is no need to go into the particulars of its working. 

What is true is that, in any case, whether with the common microscope, or with the superresolution microscope, in order to be observed, the object points must be submitted to some kind of interaction. Since we are dealing with optical microscopes, the interaction occurs with photons. In such circumstances the photon, on interacting with the microparticle, is diffused by it. As a result of this interaction, which is fundamental in all direct concrete quantum measurements, a certain amount of momentum is transferred from the photon to the microparticle, leading to an uncertainty in the momentum of the microparticle. 

Watanabe, T., Iketaki, Y., Omatsu, T., Yamamoto, K., Ishiuchi, S., Sakai, M. and Fujii, M. (2003) Two-color far-field superresolution microscope using a doughnut beam. Chem. Phys. Lett., 371, 634-639. 

Schemes for achieving 3D spatial superresolution (see Section 12.4) will continue to proliferate, and at the same time microscopes...

The superresolution optical microscope shown in Fig. 28 is basically made up of a sensor or light detector, a scanning system, (not shown in the sketch), designed to control the position of the probe over the sample, and a computer with a display device. Naturally it also has, as does any conventional... 

For this type of superresolution optical microscope, experiments have shown that it is possible to have spatial resolutions of the order of X/50. It is believed that the technique can be improved so to allow spatial resolutions of over X/100. 

Let us now consider the well-known Heisenberg microscope experiment, with both the common Fourier microscope and the new-generation superresolution optical microscope. 

Some may argued that these superresolution optical microscopes work only with a large number of photons and, consequently, are no good, that is, appropriate, when only a single photon is diffused. If this claim had any grounds, then it should also be applied to the common Fourier microscope. Nevertheless, it can easily be shown that, in principle, these two types of microscopes can... 

The product of these uncertainties in momentum and in position, lies in the case of the common Fourier microscopes in the Heisenberg uncertainty measurement space, while for the superresolution optical microscope, the same product lies in the more general wavelet uncertainty measurement space. 

The optical layout for the measurement of biological samples (cells) is shown in Figure 29.3b. The sample was irradiated with co-linear IR and visible light beams. The transient fluorescence from the sample was collected from the opposite side by an objective lens. In this optical layout, the spatial resolution was determined by the objective numerical aperture (NA) and the visible fluorescence wavelength IR superresolution smaller than the diffraction limit of IR light was achieved. Here, Arabidopsis thaliana roots stained with Rhodamine-6G were used as a sample. We applied this super-resolution infrared microscope to the Arabidopsis thaliana root cells, and also report the results of time-resolved measurements. 

M. Schrader, S.W. Hell, Three-dimensional superresolution with a 4pi-confocal microscope using image restoration, J. Appl. Phys. 84, 4034-4042... 

The use of a single LED source has its advantages that the microscope developed is simple, small and portable. But it also suffers from some disadvantages like poor axial resolution because of under-sampling. To overcome this pixel superresolution (SR) techniques have been followed, where a super-resolution picture is obtained from a series of low-resolution images. Each image in... 

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