Related Experiment Video
Updated: Jun 15, 2026
16:11
Implementation of a Reference Interferometer for Nanodetection
Published on: April 26, 2014
All-reflection Michelson interferometer: analysis and test for far ir Fourier spectroscopy
Applied Optics
|March 4, 2010
Summary
Lateral errors in diffraction gratings of Michelson interferometers cause phase shifts. Careful instrument design is needed to prevent cross-order interference in Fourier transform spectroscopy.
Area of Science:
- Optics and Spectroscopy
- Interferometry
- Diffraction Gratings
Background:
- Michelson interferometers are crucial for spectroscopy.
- All-reflection interferometers utilize diffraction gratings as beam splitters.
- Understanding error effects is vital for instrument precision.
Purpose of the Study:
- To analyze the impact of lateral grating errors on Michelson interferometer performance.
- To investigate phase shifts and interference effects caused by grating misalignment.
- To validate the analysis with experimental data from a Fourier transform spectrometer.
Main Methods:
- Theoretical analysis of lateral grating displacement effects.
- Mathematical modeling of phase shifts and wavenumber dependence.
- Experimental testing of a Fourier transform spectrometer prototype (500-1000 microm).
Main Results:
- Lateral grating errors introduce a wavenumber-independent phase shift proportional to grating order.
- Experimental results align with the theoretical analysis.
- Cross-order interference is predicted for multi-order wavenumbers, potentially affecting efficiency.
Conclusions:
- Lateral grating errors are a significant factor in all-reflection Michelson interferometers.
- The study quantifies phase shifts and identifies potential interference issues.
- Design considerations must address these errors for accurate Fourier transform spectroscopy.
Related Concept Videos
01:25IR Spectrometers
There are two main infrared (IR) spectrophotometers: dispersive IR spectrometers and Fourier transform infrared (FTIR) spectrometers. In a dispersive IR spectrometer, a beam of infrared radiation produced by a hot wire is divided into two parallel equal-intensity beams using mirrors. One beam passes through the sample, while another is a reference beam. The beams then move through the monochromator, which separates the radiations into a continuous spectrum of different frequencies. The...
01:26Raman Spectroscopy Instrumentation: Overview
A conventional Raman spectrophotometer includes a laser source, a sample holding system, a wavelength selector, and a detector.
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
01:09Infrared (IR) Spectroscopy: Overview
When electromagnetic radiation passes through a material, atoms or molecules transition from a lower to a higher energy state by absorbing radiation corresponding to the energy difference between the two states. The absorption of infrared (IR) radiation causes transitions between vibrational energy levels in a molecule. Therefore, IR spectroscopy is a useful analytical tool for determining the molecular structure of molecules.
Different compounds display unique properties due to their...
Different compounds display unique properties due to their...
01:24IR Spectroscopy: Molecular Vibration Overview
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
01:03IR Frequency Region: Fingerprint Region
IR spectra are divided into two main regions: the diagnostic region and the fingerprint region. The diagnostic region of the spectrum lies above 1500 cm−1. The absorptions resulting from single-bond vibrations of the N–H, C–H, and O–H stretch at higher wavenumbers and appear on the left side of the spectrum. The stretching absorptions of the C≡C and C≡N occur between 2100–2300 cm−1. In contrast, those arising from stretching absorptions of the C=O, C=N, and C=C occur between 1600–1850 cm−1.
The...
The...
01:11Applications of IR Spectroscopy: Overview
The non-destructive nature and ability to provide valuable chemical information make IR spectroscopy a versatile technique with broad applications in various scientific and industrial fields. IR spectroscopy is commonly used to identify and characterize organic and inorganic compounds. It provides information about the functional groups present in a molecule and the bonding between atoms. This helps in the structural elucidation of compounds during organic synthesis, pharmaceutical research,...