Michelson interferometer is its sensitivity to vibrations and air currents 4. The change in optical path length of the right hand beam is 2 x 5 cm x n air 1 n. Measuring the refractive index of a gas in one arm of a michelson interferometer, a glass chamber is placed with attachments for evacuating the inside and putting gases in it. Determination of the refractive index of a glass block using. Students can measure the wavelength of light and the indices of refraction of. The michelson interferometer has long been a popular piece of equipment in the physics under graduate laboratory. Interferometry, michelson and fabryperot interferometer.
This technique allows us the determination of the refractive index of a given liquid or a transparent sample accurately to high precision, with an accuracy limited only by the precision in the. Pdf an experimental method for determination of the refractive. Fabryperot interferometer l incident reflected transmitted resonance condition. Introduction a michelson interferometer is a device used to measure very small distances by observing the. The validated test was performed on a birefringent crystal csbn50 with the estimated accuracy being up to 10.
Michelsons interferometer refractive index of glass. The instrument consists of a halfsilvered mirror that divides a. Half of the light is sent along path b towards the movable mirror and the other half is sent down path a towards. Finally, the index of refraction was measured for light passing through a plane of glass ng 1. Alternatively, if the refractive index is known, the thickness of the plate may be. In an interferometer figure 1 a light beam in this.
This device works under the principle of interference. Pdf on oct 27, 2012, joseph vermont bandoy and others published measurement of index of refraction of air and carbon dioxide using michelson interferometer find, read and cite all the research. Align the laser source and the interferometer as described in the procedure to find the wavelength of the laser source. The michelson interferometer is the best example of what is called an amplitudesplitting interferometer. Its capable of measuring the wavelength of monochromatic light with an accuracy of better than 5%. Michelson interferometer, view interferometer, brolight. The michelson interferometer has long been a popular piece of equipment in the physics undergraduate laboratory. Figure \\pageindex1\ depicts the interferometer and the path of a. Changing the pressure of gas in the cell alters path length. Construction of a michelson interferometer for fourier. In this experiment you will use a very sensitive instrument, the michelson interferometer, to measure the small change in phase velocity of light. In this experiment the famous michelson interferometer and some of its uses are investigated. An experimental method for determination of the refractive index of liquid samples using michelson interferometer.
M1 and m2 are two plane mirrors silvered on the front surfaces. Measuring the change in the refractive index of water with a. To determine the refractive index of a thin glass plate. The michelson interferometer can also be used for making precise measurements of the index of refraction of air. A michelson interferometer consists of two ammepaths that light travels down, which end in mirrors attached around a beam splitter. The main aims of this experiment are first, to use the michelson interferometer to measure the refractive index of samples of glass and mica and. When set up correctly the michelson interferometer is used in conjunction with a gas cell and vacuum pump to investigatethe dependence of the refractiveindex of airon the pressure and to simply measure the refractive index of air. Using a beam splitter, a light source is split into two arms. Consider a thin glass plate of thickness t and refractive index n, inserted normal to the path of one of the two interfering beams in michelson interferometer. The refractive index n can also be defined for a particular material as the ratio of the speed of light in. Figure 1 depicts the astonishingly simple design of the michelson interferometer.
When set up correctly the michelson interferometer is used in conjunction with a gas cell and vacuum pump to. The michelson interferometer in 1881, 78 years after young introduced his twoslit experiment, a. Michelson interferometer fabryperot interferometer the experiment. Origin of the index of refraction of a material medium 1 the apparatus 4 the michelson interferometer 4 gashandling system 8 fringecounting electronics 9 prelab problems 12 procedure initial setup data collection 14 data analysis 15. Refractive index sensor based on an abrupt taper michelson.
Group refractive index measurement by michelson interferometer. The refractive index also depends on the wavelength colour of the light ray. Michelson interferometer, the refractive index of a gas goal. A michelson interferometric technique for measuring refractive index of sodium zinc tellurite glasses deepak n. The experimental setup is a modified michelson interferometer employing a novel. The michelson interferometer invented by the american physicist albert a. Michelson interferometer, gas cell, compensator, absolute pressure gauge, cylinder with helium gas, vacuum pump.
Theory in 1887, albert michelson built his interferometer originally to investigate the existence of ether. A michelson interferometer illuminated by a polychromatic light source was used to measure the time of flight of a light pulse or intensity substructure through a sample of optical material. The optical path length of the beam through the plate is nt, while the optical path length through an equal thickness of air is just t. Refraction index of air and co 2 with michelson interferometer phywe series of publications laboratory experiments physics phywe systeme gmbh 37070 gottingen, germany 22207 1 related topics interference, wavelength, phase, refraction index, light velocity, virtual light source. A recently developed method which allows for the measurement of the index of refraction of semiconductor wafers is an adaptation to the michelson interferometer that combines both michelson and fabryperot interferometry 4. Using a michelson interferometer to measure the index of. A michelson interferometric technique for measuring refractive index. The schematic setup for the michelson interferometer is going to be. The michelson interferometer is a historically important device which provides simple interferometric configuration for introducing basic principles. Change in pressure change in index of refraction different wavelength. Thomas young was the first to develop an interferometer, he allowed a single, narrow beam of light to fall on two narrow, closely spaced slits a double slit.
Using a michelson interferometer to measure the index of refraction of air kimberly belmes, carly stau er department of physics, paci c lutheran university tacoma, wa 98447 october 2, 2017 october 23, 2017 abstract using a michelson interferometer, we experimentally measured the index of refraction. Study the effective a temperature and concentration on refractive index of water by using michelson interferometer article pdf available october 2015 with 2,622 reads how we measure reads. By comparison of refractive index values from sdm and arm, their refractive index uncertainties values were lower than 0. Evacuating the air from the chamber causes a shift of 60 fringes. The michelson interferometer and the hene laser university. Place the rotation stage perpendicular to the optical path, between the beam splitter and the movable mirror. Notes on the michelsonmorley interferometer how it works a monochromatic light wave has one frequency or wavelength. Jan 20, 2020 the michelson interferometer invented by the american physicist albert a.
Yam,2 and hanspeter loock3 1department of physics, engineering physics, and astronomy, queens university, kingston, ontario, k7l 3n6, canada 2department of electrical and computer engineering, queens university, kingston, ontario, k7l 3n6, canada. Pasco scientific 01205187c precision interferometer is used in michelson mode to investigate wavelengths and refractive indices. The index of refraction of gasses using a michelson. The beamsplitter is now mounted in between mlitors mj and mi on a manual. Two weights for all experiments with michelson interferometer. A michelson interferometric technique for measuring. Schematic illustration ofa michelson interferometer. Introducing the apparati determine the wavelength of hene laser separately for each interferometer. Calculate the refractive index of glass by using michelson interferometer. A comparison of the usefulness of the michelson interferometer with other interference techni. The michelson interferometer and its modifications are used in the optical industry for testing lenses and prisms, for measuring index of refraction, and for examining minute details of surfaces microtopographies. Experimental values obtained for refractive indices of the twelve water samples are presented.
In this lab we measure the wavelength of light from a helium neon laser, the index of refraction of air, and the thermal coefficient of expansion of copper. Michelson interferometer objectives of the experiment 1. On the use of a michelson interferometer to determine indices. Michelson interferometers can be used to find out the refractive index of glass plates or thin films. Alternatively, if the refractive index is known, the thickness of the plate may be determined. An experimental method for determination of the refractive. Each method uses interferometry as the means for their measurement of the refractive index. In your lab notebook leave space for an introduction that describes the michelson interferometer. Michelson interferometer lab report robert clancy 04329741 november 9, 2005 abstract in this experiment the famous michelson interferometer and some of its uses are investigated. The michelson interferometer is one example of an optical interferometer, including fabryperot, machzender, etc. Michelson designed and built an interferometer using a similar principle. Interferometers are basic optical tools used to precisely measure wavelength, distance, index of refraction, and temporal coherence of optical beams.
Figure \\pageindex1\ depicts the interferometer and the path of a light beam from a single point on the extended. Measuring the refractive index of infrared materials by dual. These are basic optical tools used to precisely measure wavelength, distance, index of refraction, and temporal coherence of optical beams etc. You will need to spend some time in the library doing some research for this aspect of your notebook. Based on the modified michelson interferometer and phase analysis method, a highaccuracy method for probing the refractive index ri of transparent medium is proposed. Introductory michelson interferometer os8501 products. Michelsons interferometer wavelength of laser beam. To use the interferometer to measure the wavelength of laser light.
The index of refraction depends not only on the composition of the gas but also on the frequency of the light, so you will perform measurements using both a red laser and a green laser. P is linearly proportional to the change in index of refraction. An accurate method for measuring the refractive index of liquids is proposed, modeled, and experimentally verified. Determination of the refractive index of a glass block. Michelsons interferometer refractive index of glass plate. Measuring the refractive index of infrared materials by. Department of physics and astronom y, university of sheffield second year laboratory 1 aims the main aims of this experiment are first, to use the michelson interferometer to measure the refractive index of samples of glass and mica and air and second, to identify three unknown gases on the basis of the value of their refractive index.
Picture shows a schematics of a setup utilized to measure the refractive index of a gas. Determining the refractive index of liquids using a. Michelson, 18521931 is a precision instrument that produces interference fringes by splitting a light beam into two parts and then recombining them after they have traveled different optical paths. One possible application is the measurement of the refractive index of a thin parallelside plate of transparent material of known thickness. The instrument used to compare optical path lengths is the michelson interferometer. A change in pressure causes a change in index of refraction. It was invented in1893 by albert michelson, to measure a standard meter in units of the wavelength of the red line of the cadmium spectrum. The main features of the interferometer are shown schematically in figure 1.
When light from the laser encounters the beam splitter it is divided in half. Setup a vacuum cell is placed along one path of a michelson interferometer. The refractive index of air with a michelson interferometer. As the laser beam interferes with another beam from a second leg of the interferometer, an. Pdf measurement of index of refraction of air and carbon. Michelson interferometric setup for measuring refractive index of. Its easier to use, more compact, and less expensive than pascos advanced interferometer. Pdf direct measurement of the absolute light refractive index of air. Twymangreen test of optical components qualitatively 1. The michelson interferometer equipment preparation goals of.
To adjust the michelson interferometer so that circular, straight line and white light fringes can be observed. Refractive index sensor based on an abrupt taper michelson interferometer in a singlemode. From these data, find the index of refraction of air at atmospheric pressure. The operation of an interferometer of this type is based. The michelson interferometer is a common configuration for optical interferometry and was invented by albert abraham michelson. Index of refraction the refractive index is a dimensionless parameter that helps us in our estimation or determination of the degree of bending of a ray of light entering one medium from another. Determining the refractive index of liquids using a modified. In this part you will use an interferometer and vacuum cell to determine the index of refraction of air. Michelson designed and built an interferometer based on the interference principle similar to that used in youngs double slit experiment details will be discussed in the lecture class. Originally michelson designed his interferometer as a means to test for the existence of the ether, a.
A michelson interferometer figure 1 can be used to measure changes in the index of refraction by inserting a watercontaining cell in one leg of the interferometer and letting the laser beam pass through the water. Read the textbook description of the michelson interferometer given in our textbook, pages 977978. Index of refraction n of air introduction in this experiment you will measure the index of refraction of air by comparing the optical path lengths of two columns of air of equal physical length but at different pressures. The principle works of a michelson interferometer are shown in.
Pdf study the effective a temperature and concentration. Bread board, diode laser with power supply, beam splitter, mirrors with mount m 1, m 2, rotation stage with slide of glass, screen. During this process, the interference rings draw togeth. On the use of a michelson interferometer to determine.
The first section of the lab was to correctly configure the michelson interferometer and to achieve proper alignment of the laserinterferometer setup so that the fringe pattern was easily visible. Wavelength and refractive indices from interferometry. The experimental setup is a modified michelson interferometer employing a novel liquid chamber that allows the optical pathlength to be continuously varied without moving a mirror. Experiment 8 michelson interferometer 1 introduction. Measurement of refractive index using a michelson interferometer. M1 and m2 are two plane mirrors silvered on the front. This is accomplished by using white light fringes superimposed on. Michelson interferometer should not be used for general applications in this region. Nov 06, 20 the refractive index of air with the air cell in the uncompensated leg. When a gas is allowed to slowly fill the container, a total of 236 dark fringes are counted to move past a reference line. It is an amplitudesplitting interferometers devised by albert michelson in 1890, the first american physicist to receive the nobel prize 1907 for work in optics.
The michelson interferometer university of sheffield. To investigate how changes in pressure affect the index of refraction of air. The michelson interferometer the michelson interferometer is described in section 25. In this way the group index of optical materials fused silica and schott glass f3 was measured with an accuracy of 104. The michelson interferometer is illustrated in fig. Each of those light beams is reflected back toward the beamsplitter which then combines their amplitudes using the superposition principle. To use the interferometer to measure the index of refraction of air. Michelson the michelson interferometer is historically important, and also provides a simple interferometric configuration for introducing basic principles. They are mounted vertically on two rigid holders placed at the sides of a flat metal stand.
Measuring the change in the refractive index of water with. On the use of a michelson interferometer to determine indices of refraction john grasel 5082011 abstract the index of refraction of helium gas was measured by recording the number of fringes traversing the output of a michelson interferometer as the helium pressure in an optical cell increased. The first of these nondestructive methods uses a michelson interferometer to measure the index of refraction of a thin wafer. The first section of the lab was to correctly configure the michelson interferometer and to achieve proper alignment of the laser interferometer setup so that the fringe pattern was easily visible. Using a michelson interferometer to measure the index of refraction of air kimberly belmes, carly stau er department of physics, paci c lutheran university tacoma, wa 98447 october 2, 2017 october 23, 2017 abstract using a michelson interferometer, we experimentally measured the index of refraction of air, n air. Using michelson interferometer, one can to calculate the refractive index of a thin film. The basic idea is to split a beam of light into two beams. Refraction index of air and co2 with michelson interferometer. The index of refraction of gasses using a michelson interferometer introduction 1 theory. Iyer a thesis presented to the graduate and research committee oflehigh university in candidacy for the degree of master ofscience in electrical engineering lehigh universitv december 2006.
709 12 701 211 365 616 269 1260 472 1165 1090 940 715 1134 1150 641 1263 309 1301 1389 565 1537 700 503 698 1625 981 1473 828 227 1326 137 358 375 457 489 397 185 380 545 909 865