Michelson system

Figure 12. Theoretical maximum solid angle for a standard Michelson system as a function of resolving power compared to field-widened interferometer operating point.

The two main differences between MCFT and conventional FT-Raman are both derived from the characteristics of the CCD, and both are fundamental. First, the resolution depends on the number of CCD elements along the interferogram axis. Since one cannot arbitrarily vary the size of the CCD or the pixel spacing, there is less flexibility than with a Michelson system, where mirror travel and sampling rate are variable. For the configuration shown in Figure 9.17, Eq. (9.8) applies (23) ... 

A simple Michelson interferometer. If we place two mirrors at the end of two orthogonal arms of length L oriented along the x and y directions, a beamsplitter plate at the origin of our coordinate system and send photons in both arms trough the beamsplitter. Photons that were sent simultaneously will return on the beamsplitter with a time delay which will depend on which arm they propagated in. The round trip time difference, measured at the beamsplitter location, between photons that went in the a -arm (a -beam) and photons that went in the y arm (y-beam) is... 

In the mid-IR, routine infrared spectroscopy nowadays almost exclusively uses Fourier-transform (FT) spectrometers. This principle is a standard method in modem analytical chemistry45. Although some efforts have been made to design ultra-compact FT-IR spectrometers for use under real-world conditions, standard systems are still too bulky for many applications. A new approach is the use of micro-fabrication techniques. As an example for this technology, a miniature single-pass Fourier transform spectrometer integrated on a 10 x 5 cm optical bench has been demonstrated to be feasible. Based upon a classical Michelson interferometer design, all... 

FT-IR utilizes the Michelson interferometer rather than the grating or prism of the dispersive system. The Michelson interferometer has two mutually perpendicular arms. One arm of the interferometer contains a stationary, plane mirror the other arm contains a moveable mirror. Bisecting the two arms is a beamsplitter which splits the source beam into two equal beams. These two light beams travel their respective paths in the arms of the interferometer and are reflected back to the beam splitter and on to the detector. The two reunited beams will interfere constructively or destructively, depending on their path differences and the wavelengths of the light. When the path lengths in the two arms are the same, all of the frequencies... 

Optical System. As shown in Figure 11, the optical section of the instrument consists of a beamsplitter, two optical wedge mirrors and a detector section with associated detector collection mirror. This is basically the Michelson interferometer technique except that the end mirrors have been replaced by optical wedges mirrored on the back side. The two windows are necessary only to maintain an ambient pressure in the Interferometer section, and a vacuum in the detector section. The window on the detector can be replaced with an optical filter if only a selected spectral region is to be investigated. 

Stella, V. J., Michelson, T. J., and Pipkin, J. D. Prodrugs The control of drug delivery via bioreversible chemical modification. In Juliano, R. L. (ed.), Drug Delivery Systems Characteristics and Biomedical Applications. New York Oxford University Press, 1980, pp. 110-170. 

A Bomem Michelson 102 FTIR equipped with a Csl beamsplitter and DTGS detector was used to collect spectra. Spectra were collected at 4 cm-1 resolution requiring approximately 6 seconds per scan and processed using Spectra-Calc software on a PC AT type system. 

In its basic design, the equipment is similar to a 2-D TL glow-curve system as described previously, but with the addition of a modified Twyman-Green, Michelson type, interferometer between the oven and the photomultiplier. As the sample is heated, the TL signal is recorded while the movable mirror of the interferometer is scanning a given optical path difference in a preset number of steps. The interference pattern corresponding to each one-way scan... 

A schematic diagram of a Michelson interferometer, the heart of the FTIR system, is shown in Figure 1 (2). The Michelson interferometer modulates each wavelength in the infrared region at a different frequency in the audio range. 

A modification of an interferometrically-based system, which was first described by Dohi and Suzuki (24), is known as a selectively-modulated interferometric dispersive spectrometer, this system is a hybrid in that a rotating grating (a dispersive element) is used to limit the number of wavelengths which can interfere at any one time in a modified Michelson interferometer. 

Michelson, E.L. (1991) Calcium antagonists in cardiology update on sustained-release drug delivery systems. Clin. Cardiol., 14 947-950. 

Fig. 7.1. Layout of the infrared spectrometer showing the Michelson Interferometer Optical System. An FTIR spectrometer s optical system requires two mirrors, an infrared light source, an infrared detector and a beamsplitter. The beamsplitter reflects about 50% of an incident light beam and transmits the remaining 50%. One part of this split light beam travels to a moving interferometer mirror, while the other part travels to the interferometer s stationary mirror. Both beams are reflected back to the beamsplitter where they recombine. Half of the recombined light is transmitted to the detector and half is reflected to the infrared source.

Pougnet, M., Downing, B., Michelson, S. Microwave irradiation systems for laboratory pressure vessels. J. Microw. Power Electromagn. Energy 28, 18-24 (1993)... 

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