Abstract
The problem of bad contrast in conventional microscopy is well-known and was solved in part by colouring the samples. It is shown theoretically that a laser Fourier holographic microscope produces images undisturbed by speckle-noise. A laser holographic microscope (LHM) is investigated experimentally. The instrument uses visible radiation of λ = 0.514 µm, Mach – Zehnder scheme optical setup, and CCD detector of the hologram. Images are reconstructed digitally. The standard slide of Parascaris Univalens Iarva (ascaris) is studied without any drying as for electron microscope. Comparison of the pictures of the same ascaris cell, observed by the LHM and high-quality Nikon conventional optical microscope with immersion oil and green filter indicates dramatically different contrast. The ultrahigh contrast of the LHM gives much more micromorphological information.
Highlights
A conventional optical microscope (COM) [1] is a popular human instrument, which will hardly fall into oblivion
The contrast of the image obtained with the laser holographic microscope (LHM) is considerably higher than by the COM
The ultrahigh contrast of the LHM is assumed to be explained by the high coherence of the laser radiation, which allows separating neighbor structures with various resonance absorption frequencies
Summary
A conventional optical microscope (COM) [1] is a popular human instrument, which will hardly fall into oblivion. Light emitted from a lamp is a carrier of information in a COM. It is incoherent visible radiation with the central frequency ω 0 and bandwidth ∆ω 0. When the spectral filters are used ∆ω 0 ≈ 1013 Hz. For a gas laser ∆ω 0 ≈ 105 Hz. The contrast of the image observed with a COM is defined by the probability of absorption the incident light by the sample matter. The contrast of the image observed with a COM is defined by the probability of absorption the incident light by the sample matter This probability depends of the molecular structure [3, 4]. To increase the contrast one has to decrease ∆ω 0
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