High-resolution Michelson Interferometer Research Articles

Applications using high-Tc superconducting terahertz emitters.

Using recently-developed THz emitters constructed from single crystals of the high-Tc superconductor Bi2Sr2CaCu2O8+δ, we performed three prototype tests of the devices to demonstrate their unique characteristic properties for various practical applications. The first is a compact and simple transmission type of THz imaging system using a Stirling cryocooler. The second is a high-resolution Michelson interferometer used as a phase-sensitive reflection-type imaging system. The third is a system with precise temperature control to measure the liquid absorption coefficient. The detailed characteristics of these systems are discussed.

Development of high resolution Michelson interferometer for stable phase-locked ultrashort pulse pair generation

We developed a high resolution Michelson interferometer with a two-frequency He-Ne laser positioning system in order to stabilize the relative phase of a pulse pair. The control resolution corresponded to a 12 as time resolution or a phase of 1.5 degrees at 900 nm. This high resolution Michelson interferometer can generate a phase-locked pulse pair either with a specific relative phase such as 0 or pi radians or with an arbitrary phase. Coherent control of an InAs self-assembled quantum dot was demonstrated using the high resolution Michelson interferometer with a microspectroscopy system.

Coherent Control of Semiconductor Quantum Wire by High-Resolution and Stable Michelson Interferometer

We developed a high-resolution Michelson interferometer in order to stabilize the relative phase of double pulses by using a He-Ne two-frequency laser positioning system. Very stable phase-locked pulse pair whose phase difference was only 4 degree at 900nm was realized.Using a high-resolution Michelson interferometer, we demonstrated coherent control of an exciton in a GaAs/AlGaAs crescent-shaped quantum wire. The dephasing time of the single quantum wire was 400fs.

Airborne FTIR measurements over the Mt Etna volcano: preliminary results from the 2003 FASA Campaign

From 16 to 26 July 2003 an extensive field campaign was carried out around Mt Etna, Sicily, Italy. During the campaign a new airborne system, Fire Airborne Spectral Analyzer (FASA), was tested. The main instrument of the payload is a high resolution Michelson Interferometer with Rotating Retroreflector (MIROR), which operates in the nominal infrared 600–3000 cm−1 spectral range with a high resolution of 0.12 cm−1. This work investigates the feasibility of using MIROR data to retrieve the surface temperature, the hyper‐spectral emissivity and the SO2 volcanic plume abundance. The results for the surface parameters show a good agreement with those obtained by satellite data and on ground measurements. In particular, the spectral emissivity shows a meaningful minimum, around 1040 cm−1, consistent with the basaltic properties of Mt Etna's surface. A sensitivity study has also been carried out to show the difficulties of SO2 columnar abundance retrieval due to the too low SO2 volcanic emission and the too high instrumental noise.

Coherent Control of Exciton in a Single Quantum Dot Using High-Resolution Michelson Interferometer

We developed a high-resolution Michelson interferometer with a He–Ne two-frequency laser positioning system, and measured the coherent carrier dynamics of a single InAs self-assembled quantum dot (SAQD) using a micro-spectroscopy system. The phase-locked double pulses were stabilized, with the maximum deviation being below 10 nm during the long measurement time of 1 h. Using this system, coherent control of an exciton in an InAs SAQD with very fine phase stabilization was demonstrated. The dephasing time of the single quantum dots was 9.5 ps which is close to that estimated from the homogeneous linewidth in the photoluminescence excitation (PLE) spectrum.

Validation of fascod3 and modtran3: comparison of model calculations with ground-based and airborne interferometer observations under clear-sky conditions

The validation of fascod3 and modtran3 against ground-based and airborne high-resolution Michelson interferometer measurements under clear-sky conditions is presented. Important considerations including water vapor continuum, frequency-dependent sea surface emissivity in the IR window region, and spectral resolution of modtran3 in the comparison of model calculations with high-resolution interferometer measurements are discussed. Our results indicate that it is not adequate to assume sea surface emissivity of 1.0 [?(ν) = 1.0] or a constant in the simulation of upwelling radiance observed by the airborne Michelson interferometer. The use of spectral emissivity (frequency-dependent emissivity) leads to much better agreement between model calculations and interferometer measurements in the IR window region from 750.0 to 1050.0 cm(-1). This could have important implications for the retrieval of sea surface temperature, thin cirrus properties, and aerosol parameters because of the sea surface emissivity of 1.0 assumption commonly used by many researchers. Comparisons of modtran3 calculations with interferometer measurements show that the agreement might not be adequate at the nominal resolution of 2.0 cm(-1), and further spectral degradation might be necessary to improve the agreement between measurements and modtran3 calculations. modtran should be used with caution for relatively high spectral resolution remote-sensing applications.

Measurement of stratospheric trace constituent distributions from balloon-borne far infrared observations

Far infrared limb thermal emission spectra obtained from balloon borne measurements made as a part of the Balloon Intercomparison Campaign (BIC) have been analyzed for retrieval of stratospheric trace constituent distributions. The measurements were made with a high resolution Michelson Interferometer and covered the 15–180 cm −1 spectral range with an unapodized spectral resolution of 0.0033 cm −1. The retrieved vertical profiles of O 3, H 2O, HDO, HCN, CO and isotopes of O 3 are presented. The results are compared with the BIC measurements for O 3 and H 2O made from the same balloon gondola and with other published data. A comparison of the simultaneously retrieved profiles for several gases with the published data shows good agreement and indicates the validity of the far infrared data, the retrieval techniques and the accuracy of the inferred profiles.

Far infrared remote sounding of stratospheric temperature and trace gas distributions

The thermal emission spectrum of the Earth's stratosphere in the far infrared exhibits rotational transitions of a large number of trace constituents in addition to the magnetic dipole lines of molecular oxygen. Stratospheric lines that have been identified in the far infrared spectrum include H2O, O3, HNO3, N2O, CO, HCl, HF, HCN and OH. This paper discusses the potential usefulness of far infrared thermal emission measurements for simultaneous retrieval of temperature and constituent distributions. A description of the high-resolution Michelson interferometer currently employed for balloon-borne far infrared stratospheric studies is given, along with a summary of the mode of limbscan observations and an example of an observed spectrum. Numerical results based on synthetic limb radiance data for model atmospheres are presented. Formal inversion techniques with a radiative transfer model based on line-by-line transmittance calculations are employed.

Balloon-borne stratospheric far-IR spectral absorption measurements: the design of a solar telescope and high-resolution Michelson interferometer combination

The design, construction, and performance of a combined solar telescope and Michelson interferometer for balloon-borne stratospheric far-IR absorption studies is discussed in terms of the relevant parameters and precautions necessary to obtain high resolution radiometrically calibrated spectra of the stratosphere between 20 and 100 cm(-1). Preliminary data are presented to indicate that the system performed as designed and provided constituent concentration values for H(2)O and O(3) from measurements of strong absorption lines in this spectrum.

Simultaneous spectroscopic measurements of stratospheric species: O3, CH4, CO, CO2, N2O, H2O, HCl, and HF at northern and southern mid‐latitudes

Near‐infrared solar absorption spectra have been recorded in the course of balloon flights from Palestine, Texas, (32°N latitude) in May 1976, and Broken Hill, Australia, (30°S latitude) in March 1977. The northern flight was made at a float altitude of 37 km and covered the spectral region from 1800 cm−l to 3600 cm−1, which encompasses infrared transitions of O3, CH4, CO, CO2, N2O, H2O, and HCl. The flight in the southern hemisphere, from a float altitude of 39 km, covered the spectral region from 2800 cm−l to 4500 cm−1, which includes useful transitions for all of the above gases (with the exception of CO) and encompasses as well the 1‐0 fundamental band for HF. Both sets of spectra were acquired at sunset by using a high‐resolution (0.13 cm−1) Michelson interferometer. The simultaneous profiles of concentration derived from the spectra for the individual gases covered in each flight are presented and discussed. While the results show few differences between the profiles at the northern and southern latitudes, there are several aspects of general importance; these include lower values for stratospheric CO than had previously been reported (i.e., ∼10 ppbv), and water vapor profiles in both hemispheres showing an increase with altitude considerably in excess of that to be expected from CH4 oxidation alone. The shape of the profile for HF was found to be consistent with model predictions, but the HF concentrations were lower by a factor of 3 or 4 than those predicted.

Carbon dioxide spectral line frequencies for the 43-μm region

The frequencies of CO(2) lines in the 3.77-4.26-microm region, which were obtained experimentally, have been compared with those listed on two tapes of the AFCRL Atmospheric Absorption Line Parameters Compilation. The experimental line frequencies were obtained in absorption using a high-resolution Michelson interferometer. Discrepancies between the present experimental values and the frequencies listed on the AFCRL tapes are tabulated. Consistency checks were also made by comparing calculated line frequencies with those on the tapes, and these findings are also reported.

High resolution Fourier transform spectrometer (0005 cm^−1) for the 06–100-μm spectral range

The construction of a high resolution (0.005-cm(-1)) Michelson interferometer with cat's eye retroreflectors is described in some detail. The instrument line shape function of the Fourier spectrometer at 0.63 microm agrees with theory at 0.02-cm(-1) resolution. Absorption spectra of gases have been measured using a 40-m White cell. Infrared luminescence spectra have also been measured using a calcium fluoride crystal doped with divalent dysprosium, cooled to 4.2 K, and excited with radiation from a quartz halogen lamp.

The HF:HCl ratio in the 14‐38 km region of the stratosphere

Near infrared absorption spectra covering the 1‐0 bands of HF and HCℓ were recorded with a high resolution Michelson interferometer during a balloon flight near Broken Hill, Australia (30.5°S, 138.5°E) in March 1977. The ratio of the number density of HF to that of HCℓ as a function of altitude in the stratosphere was deduced from measuremnts of the Rl features of both gases. The experimental errors vary over the altitude range covered by the measurements, their estimated values being ±25% between 14 and 30 km, increasing to ±50% at the extremes of the range (14 and 38 km). Within these estimated errors the ratio is constant, its mean value being HF:HCl = 0.1.

A high-resolution Michelson interferometer for the Isaac Newton Telescope

A high-resolution Michelson interferometer for the Isaac Newton Telescope

High resolution infrared spectra of the earth's atmosphere III—airborne observations in the 100–140 cm −1 range

The spectral emission of the lower stratosphere in the far infrared region (100–140 cm −1) has been measured with a high resolution (0.02 cm −1) Michelson interferometer from the Gerard P. Kuiper Airborne Observatory flying at 13 km altitude. The observed spectra are compared with synthetic emission spectra in order to perform the line assignment. Most of the lines in this spectral range are due to the major atmospheric absorbers (H 2 16O, O 2, O 3). The measured line frequencies, for these constituents, are in excellent agreement with their predicted values (within 0.005 cm −1). A number of lines have been attributed to HDO, H 2 17O and H 2 18O and their measured frequencies are listed. A few observed lines remain unassigned and are not thought to be due to the above constituents or to CO, N 2O and NO whose lines are included in our synthetic spectra.

High resolution Michelson interferometer for airborne infrared astronomical observations 1: Concept and performance

A Michelson interferometer has been built for use with the 91-cm telescope on NASA's Gerard P. Kuiper Airborne Observatory primarily to measure ir line emission from H 11 regions. Operation is in the rapid scan mode, and the achievable resolution is 0.02 cm(-1) in the wavelength range from 10 micro to around 300 micro. A minicomputer is used to provide on-line spectrum displays and to control and monitor the instrument performance. The design and use of the instrument is discussed, and a comparison is made between the theoretical performance and that actually achieved on the first flights when measurements of line emission from the Orion nebula and from the atmosphere were made.

High resolution Michelson interferometer for airborne infrared astronomical observations 2: System design

A Michelson interferometer for high resolution (lambda/Deltalambda approximately 10(4)) spectroscopic observations of astronomical ir ionic line emission has been built and flown on the NASA 91-cm airborne ir telescope facility (G. P. Kuiper Airborne Observatory). In Part 1 of this paper the requirements for such a system were outlined, and the scientific basis for the choice of instrumental parameters and the rapid scan mode of operation were discussed. In this paper design details of the instrument are presented. These include the optics, control He-Ne laser interferometer, helium-cooled bolometer detector, and cooled passband filters. In addition, the on-line computer software which enables the operator to interact rapidly with the system to produce inflight spectra and control accordingly the observational parameters is described, as are elements of the electronics hardware developed specially for airborne observations.

Atmospheric spectroscopy at very high resolution in the middle infrared with a rapid-scan Michelson interferometer

A high resolution Michelson interferometer (λ/Δλ/ ∼ 10 4) has been built for use on the NASA C141 i.r. airborne telescope to study far i.r. emission lines from HII regions. In preparation for the first airborne measurements, the instrument has recently been used on the 1 m telescope at the Observatoire du Pic du Midi. Atmospheric emission spectra were obtained between 17.5 and 20 μm at a spectral resolution of 0.02cm −1; line identifications tabulate numerous H 2O rotation lines throughout the “18 μm window”. Limits were put to the integrated water vapour above the site and upper limits to the intensities of two ionic emission lines of Sulphur in the Orion nebula.

High Resolution Michelson Interferometer for Spectral Investigations of Lasers

An extremely stable Michelson interferometer with an optical path difference up to several thousand meters has been developed for the precise investigation of the frequency behavior of lasers. The theoretical value for the spectral resolution is of the order of 10(12). The spectral resolution of a real system is determined by external disturbances and was measured to be close to 10(1l). The capability and the characteristics of the system are discussed.

High-resolution Michelson interferometer for the spectral investigation of lasers

High-resolution Michelson interferometer for the spectral investigation of lasers