A Michelson Interferometer is a device used to measure the speed of light in precise optical measurements. It does this by splitting light into two or more beams that recombine and interfere with each other causing the interference fringes. The interferometer basically consists of a light source, a beamsplitter, and two (or more) mirrors to reflect the light.
The interference pattern for a Michelson interferometer is circular-- that is, it produces concentric circles of light and dark "fringes". When one mirror on the interferometer is moving, the path difference between the two split beams of light changes, and the interference pattern is seen
Interference is a phenomenon that occurs when two photons of light interact with each other in such a way that their waves sum to either increase or decrease their total amplitude. Complete constructive interference occurs when two electromagnetic waves are of the same frequency and in phase; destructive interference occurs when two electromagnetic waves of the same frequency have a phase difference of one-half wavelength. When complete destructive interference occurs, no light can be detected. Similarly, complete constructive interference results in intensity quadrupling (intensity is proportional to the square of amplitude). The following picture demonstrates these effects.
Originally, the inventors of the interferometer produced it to measure the speed of light so they could determine the existence of ether. Since then it has been important in measuring the wavelengths of light, using the wavelengths of light to measure very small distances (up to 0.5 microns), to measure extremely small times (up to 1x10-15 seconds), and to study optical media.
Albert A. Michelson (1852-1931)
The Michelson interferometer was invented by American Physicist Albert A. Michelson in 1887. Michelson was born in Strzelno (Poland) in 1852 and moved to American in 1855. When he was 17, he joined the United States Naval Academy in Anapolis, Maryland where he excelled in science subjects. Michelson later became a science instructor at the academy, but moved on to become a professor of physics at several universities. During the years of 1923-1927, he was president of the National Academy of Sciences. In 1907, he was the first American to be awarded the Physics Nobel Prize for his many efforts in optics.
Michelson began experimenting with the interferometer in April of 1887. He came up with a system of mirrors and semi-transparent mirrors (or beamsplitters) for merging separated beams of light, which are coming from the same source. The system was set up so that the beam of light was split in two, sending each split perpendicular to each other, and then merging back so they “interfered” with each other.
In 1895, Professor Wilhelm C. Roentgen, a German physicist, was working with a cathode ray tube, much like our fluorescent light bulb. The tube consisted of positive and negative electrodes encapsulated in a glass envelope. On November 8, 1895, Roentgen was conducting experiments in his lab on the effects of cathode rays. He evacuated all the air from the tube and passed a high electric voltage through it after filling it with a special gas. When he did this, the tube began to give off a fluorescent glow. Roentgen then shielded the tube with heavy black paper and discovered a green colored fluorescent light could be seen coming from a screen located a few feet away from the tube.
A spectrophotometer is an instrument that would measure the amount of light a sample would absorb. A beam of light consists of a stream of photons. These photons, when they encounter a molecule there is a chance that the molecule will absorb the photon. This absorption thus reduces the amount of photons in the beam of light and therefore
The first objective was examined by taking a series of data points with the laser configured to measure flow vel...
...nce. The intensity of the light reflected from the sample substance is also compared to the light intensity before it passes through the material. The basis of this spectroscopy is based on the concept of electronic transition. The pi electrons (electrons in a pi bond) can become excited as the molecule containing them absorbs ultraviolet and/or visible light. As a result, the electrons move to a higher anti-bonding molecular orbital. This orbital holds an electron that is located on the outside region between two nuclei. In other words, an anti-bonding orbital contains lone pairs of electrons. The difference in the orbitals determines the wavelength and frequency of the light that was absorbed by the substance. This collected data allows scientists to infer the identity of the compound. Generally, this spectroscopy is used frequently for quantitative measurements.
This process is used in forensics because it is so precise, fast, and reliable. The process includes creating a high-temperature plasma induced by a laser, which allows the user to remove a small amount of mass from the subject, known as laser ablation. This ablated mass is then further manipulated to form a high energy plasma containing free electrons and energized ions. Once the laser is turned off, the plasma will begin cooling, which will let the ions return to their natural state. When this happens, they will give off a certain spectra that will allow the user to be able to tell what exactly was in the species they experimented on (appliedspectra.com). This could be useful in determining such substances like what glass is composed of or what type of glass was
To understand this week’s experiment one must first understand what a spectroscope is and what it does. With this understanding in hand, one would gain a deeper appreciation for this lab and its intended lesson. “A spectroscope is a device that measures the spectrum of light” (Ball, 2014). More specifically a spectroscope is an instrument designed to split light from different sources into wavelengths. Humans are able to see these wavelengths as different colors. Noting the difference in colors between various light sources, those studying a given light source can identify elements of the light source.
The basic principle used in this optical amplifier is the spontaneous emission and the stimulated emission. The light will be absorbed as they propagates. Light will be amplified as they travel in the medium where in the population of light is much greater in higher energy states compared to lower energy states.
An oscilloscope is a laboratory instrument that commonly used to display and analyze the waveform of electronic signals. This device draws a graph of signal voltage as a function of time. Oscilloscope usually have two-dimensional graph which electrical potential differences represent by Y-axis (vertical) and time represent by X-axis (horizontal). With positive values going upward and negative values going downward (Ask.com, 2014). In any oscilloscope, the horizontal sweep is measured in seconds per division (s/div), milliseconds per division (ms/div), microseconds per division (s/div), or nanoseconds per division (ns/div). The vertical deflection is measured in volts per division (V/div), millivolts per division (mV/div), or microvolts per division (µV/div).
Although telescopes has been around for several hundreds of years, there has been great discrepancy as to who invented it first. Here is one authors opinion. Lippershey was a Dutch spectacle marker during the early 17th century (approximately 1600). He was one of the first who created the "looker" (now called telescope) by placing two pieces of lenses together. The discovery that placing lenses together can magnify images were made by children who took Lippershey's spectacles and looked at a distant church tower.
Stemming from the first years of the 20th century, quantum mechanics has had a monumental influence on modern science. First explored by Max Planck in the 1900s, Einstein modified and applied much of the research in this field. This begs the question, “how did Einstein contribute to the development and research of quantum mechanics?” Before studying how Einstein’s research contributed to the development of quantum mechanics, it is important to examine the origins of the science itself. Einstein took much of Planck’s experimental “quantum theory” research and applied it in usable ways to existing science. He also greatly contributed to the establishment of the base for quantum mechanics research today. Along with establishing base research in the field, Einstein’s discoveries have been modified and updated to apply to our more advanced understanding of this science today. Einstein greatly contributed to the foundation of quantum mechanics through his research, and his theories and discoveries remain relevant to science even today.
. After reflection of the two beams, they recombine at the beam-splitter. Depending on the location of the moving mirror, difference in the optic paths are generated. The two beams interfere constructively and therefore lead to a maximum detector response when they are in phase with each other. The beams interfere destructively when they are out of phase with each other. (14)(15)
Most people don't know where the idea of the laser came from. The idea for the laser came from a machine called a maser. The maser was a tool that was able to strengthen, or amplify radio and light waves. The first laser was made in California in 1960. It was built by Theodore Maiman along with a group of American scientists. The material they used for a concentrator was a man- made ruby. This was done by, coiling a simple flash tube around a rod, and beaming powerful flashes of light at it. The result was pulses of red laser light. Once they made the device they had to name it. They had think of some word or words to described it. They came up with Light Amplification by Stimulated Emission of Radiation. Using the first letter of each main word they named it laser. The laser had everyone excited.
In 1801 Thomas Young provided some very strong evidence to support the wave nature of light, he placed a monochromatic light in front of a screen with two slits cut into it, and observed an interference pattern, only possible if light was a wave. In 1965 Richard Feynman came up with a thought-experiment that was similar to Young’s experiment. In Feynman’s double-slit experiment, a chosen material is fired at a wall which has two small slits that can be opened and closed at will – some of the material gets blocked and some passes through the slits, depending on which ones are open.
Refraction is a process that occurs when light travels between media of different optical density. Light travels at a speed of roughly 3.0 × 108ms-1 in a vacuum. A vacuum has a refractive index n=1.00. The speed at which the light is travelling will decrease as it moves into differently optically
An oscilloscope is an electronic measuring instrument that creates a visible two-dimensional graph, on a screen, of one or more continuously varying voltages or currents. To read a signal in an oscilloscope the following steps are taken: voltage measurements, time and frequency measurements, pulse and rise measurements and phase shifts