A capability for scanning electron microscopy of wet biological specimens is. Fundamentals of geometrical optics stigmatic points. Scanning electron microscopy of cells and tissues under fully. Raman spectroscopy utilizing a microscope for laser excitation and raman light collection offers that highest raman light collection efficiencies. Principles of photo detection, qe, dynamic range shot noise, photodetectors pmts, photodiodes, photo resistors, understanding common metrics and specs. Capturing multiple twodimensional images at different depths in a sample enables the. Optical microscopy may be defined as the formation of a magnified image of a small. Confocal microscopy offers several advantages over conventional widefield optical microscopy, including the ability to control depth of field, elimination or. Nptel nptel online certification course lecture 22 tutorial materials characterization fundamentals of scanning electron microscopy dr. How the sem works the sem uses electrons instead of light to form an image. The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. In todays class we will look at some of the problems related to. Optical sectioning thickness as a function of na of the objective z resolution in confocal microscopy optical sectioning thickness versus confocal pinhole diameter z m pinhole diameter mm z 1 2 m na immersion oil n1. Cu, zink brass, pbsn 11 to 5 quantitative metallography and image analysis 14 to 15 6 xray powder diffraction in materials analysis 16 7 streographic projections.
Scanning probe microscopy creates images of surfaces using a probe. Imaging via light vs electron energy of photon in visible light 2 ev energy of electron beam 10 kev wavelength of visible light 600nm wavelength of electron beam 0. Work on surface profilers using optical deflection techniques. From the perspective of solid state physics, brillouin scattering is an interaction between an electromagnetic wave and one of the three abovementioned crystalline lattice waves.
Intro to optical hardware, common optomechanical assemblies week 10. Compound optical microscopes, these days, have a maximum magnification of about x and an imaging resolution of around 0. Scanning nearfield optical microscopy snom, principles of nuclear. Laser induced fluorescence, optical components and their working principles week 9. Resolution limit of optical microscopes is due to the light diffraction. Microscopy techniques pdf conventional light microscopy, fluorescence microscopy, confocalmultiphoton microscopy and stimulated emission depletion. Psf engineering g apodization, superresolution, extended depth of focus, particle trapping, confocal psf 11 20. Brillouin scattering also known as brillouin light scattering or bls, named after leon brillouin, refers to the interaction of light with the material waves in a medium.
Nonlinear optical microscopy techniques have emerged out as efficient tools for biomolecular detection and medical diagnoses in cell or tissues at the submicrometer level. Sinha scientist national metallurgical laboratory jamshedpur 831 007 introduction the most important single feature of metallographic technique is the preparation of specimens. Basic optical microscopes can be very simple, although many complex. Microscopes can be categorized by the methods that they use. Basic principles and applications of all these imaging techniques used in nanotechnology research are described below. In this lecture, we shall be discussing the principles of microscopy. Scanning probe microscopy spm 1600 light microscope 1938. The highly surfacesensitive near field or scanning probe microscopes are covered in optical sources and detectors. Nptel nptel online certification course lecture 22 tutorial materials characterization fundamentals of scanning electron. Department of physics indian institute of technology. Basics of light microscopy imaging embl heidelberg. The electron beam follows a vertical path through the column of the microscope.
The scanning electron microscope sem is one of the most versatile instruments. Scanning probe microscopy scanning tunneling microscopy stm, atomic force microscopy afm, nearfield scanning optical microscopy and others 3. Sampleprobe interaction is monitored as function of location. Lateral and axial resolutions of the optical microscope illumination in light microscopy 1. Important sub categories andor techniques will be included where possible. The probe interacts with the sample and produces a mess of electrons, xrays, light. Sankaran associate professor department of metallurgical and materials engineering iit madras email. A beam of electrons is produced at the top of the microscope by heating of a metallic filament. A geometrical optical confocality analysis is used when pd 1. Mild steel, high carbon steel, cast iron, stainless steel, 8 to 10 4 optical microscopy of non ferrous samples. Variants in the optical microscopes and image formation. Differential interference contrast microscopy wikipedia.
Sample preparation for transmission electron microscopy. Introduction it is recognized that unsymmetrical optical systems can provide better or unique solutions to certain optical design problems. Royal microscopical society, 1984 a person with normal eyesight can see clearly objects located anywhere from infinity to about 25 cm from the eye. While the resolution in twophoton fluorescence mciroscopy 2pfm is less good, photodamage is lower and penetration depth is higher compared to singlephoton confocal fluorescence microscopy 1pfm. Atomic force microscope magnetic force, lateral force, chemical force. Ultrafast dynamics in molecules, nanostructures and. Basics of nonlinear optics, optical susceptibility, 2nd and 3rd order effects, cars microscopy, 2 photon imaging 10. Indian institute of technology madras presents nptel national programme on technology enhanced learning lecture18 materials characterization fundamentals of scanning electron microscopy dr. Optical microscopy, laser diffraction particle size analyzer, coulter submicron size analyzer. Different microscopy techniques are used to study the alloy microstructure, i.
Lets look at the human eye the human eye is a very useful organ but it has several shortcomings limited field of view, limited light gathering power, limited resolution 0. Calculate the resolution of an optical microscope if the wavelength of reflected light in vacuo is 600 nm, refractive index of the medium is 1. Wear characterization and wear mapping of a coated cutting. Introduction to scanning electron microscopy youtube. It is mediated by the refractive index dependence on the material properties of the medium. The types of microscope are i light or optical microscope ii phase contrast microscope iii dark field dark ground microscope iv electron microscope light or optical microscope they are of two types namely simple and compund microscope zsimple microscope consists of a single lens. Differential interference contrast dic microscopy, also known as nomarski interference contrast nic or nomarski microscopy, is an optical microscopy technique used to enhance the contrast in unstained, transparent samples. This involves correct and representative sampling, cutting and grinding with a minimum of mechanical. Characterization techniques for nanotechnology applications.
Indian institute of technology madras presents nptel national programme on technology enhanced learning lecture17 materials characterization fundamentals of scanning electron microscopy dr. Dr otto schott formulated glass lenses that colorcorrected objectives and. Xray diffraction, optical microscopy, scanning electron microscopy. Noc optical spectroscopy and microscopy fundamentals of optical measurements and. Magnification of a compound microscope is the product of the magnification caused by the objective and ocular eyepiece lenses. Confocal microscopy, most frequently confocal laser scanning microscopy clsm or laser confocal scanning microscopy lcsm, is an optical imaging technique for increasing optical resolution and contrast of a micrograph by means of using a spatial pinhole to block outoffocus light in image formation. Optical microscopy davidson and abramowitz optical microscopy. This article gives an overview of metallography and metallic alloy characterization. Optical microscopy conventional light microscopy, fluorescence microscopy, confocalmultiphoton microscopy and stimulated emission depletion microscopy 2. Pdf nptel chemical engineering interfacial engineering. When properly designed, raman microscopes allow raman spectroscopy with very high lateral spatial resolution, minimal depth of field and the highest possible laser energy density for a given laser power. Scattering l introduction, surface scattering in systems, volume scattering models.
Module 3 microscopic techniques lecture 14 light microscopyi. However, the design of unsymmetrical optical systems is considered a difficult or obscure task. The similar thing we are doing here, just for reinforcing the understanding. The optical path aa, is rigorously nil, this shows stigmatism. The knowledge obtained is exploited for the design.
Optical microscopy davidson and abramowitz optical. Optical and electron microscopy encyclopedia of life support. Indian institute of technology madras presents nptel national programme on technology enchanced learning lecture19 materials characterization fundamentals of scanning electron microscopy dr. These particular points are youngweierstrass points, they are often used in microscopy. Nptel biotechnology bioanalytical techniques and bioinformatics. The electron optical system inside of the microscope column and a space surrounding the specimen are kept at vacuum. Polarization microscopy for minerals, phase contrast microscopy for metals, dic microscopy and confocal and other special techniques for polymers and biomaterials 3. Joint initiative of iits and iisc funded by mhrd 1820 nptel chemical engineering interfacial engineering module 2. Two years later, in 1933, ruska built an electron microscope that exceeded the resolution attainable with an optical light microscope. Optical diagrams of brightfield and darkfield microscopes. Multiphoton microscopy principle of fluorescence induced by onephoton absorption left and twophoton absorption right. And because we will be using this all the concept related to diffraction and imaging and so on, not only here in electron diffraction as well. Rapid development of new fluorescent labels has accelerated the expansion of fluorescence microscopy in laboratory applications and research 68. Indian institute of technology madras presents nptel national programme on technology enhanced learning lecture24 materials.
Metallography developed from the need to understand the influence of alloy microstructure on macroscopic properties. Optical and electron microscopy bilkent university. Nptel biotechnology bioanalytical techniques and bioinformatics joint initiative of iits and iisc funded by mhrd page 10 of 45. Optical microscopy has the limit of resolution of 2,000 a by enlarging.
Optical microscopes are the oldest design of microscope and were possibly invented in their present compound form in the 17th century. Figure 14 is an example of this conjugate image type n 1,8 et n 1. Introduction to confocal laser scanning microscopy leica. The main topics discussed would be magnification, resolution, depth of field and focus. So it becomes mandatory for primers, and more in general for all those researchers looking for answers about their biological problems that can be satisfied by using the optical microscope, to have. The normal eye is unable to focus on an object closer than about 25 cm. Optical microscopy, transmission electron microscope, scanning electron microscope. Introduction to transmission electron microscopy tem youtube. In the microscope beam path figure 5a, the object or specimen is recorded by the objective and is first projected at infinity with a parallel bundle of wavefronts or rays. Contrast is generated by absorption, scattering, etc. Tem smallest distance that can be resolved wavelength of radiation semiangle of collection refractive index of viewing medium. Dic works on the principle of interferometry to gain information about the optical path length of the sample, to see otherwise invisible features. Light microscopy conventional optical microscopes, contrast techniques, fluorescence.
Tem is a microscopy technique whereby a beam of electrons is transmitted through an ultrathin specimen. Indian institute of technology madras and nptel via swayam. Optical microscopes are used for magnified or photographic images of small. Transmission electron microscope i an extremely brief history transmission electron microscope term was first used in the paper of knoll and ruska in 1932.
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