MIPT’s Laboratory for the Spectroscopy of Planetary Atmospheres has come up with a high-resolution meter to gauge the concentration of gases in the atmosphere with unparalleled precision. The infrared spectrum radiometer is described in an article recently published in the journal Optics Express.
The paper, authored by Alexander Rodin, Artem Klimchuk, Alexander Nadezhdinsky, Dmitry Churbanov and Maxim Spiridonov, says that the new spectrum radiometer is 100 times more precise than the best available near-infrared spectrometers, and 10 times more accurate than a meter created on a similar principle recently described by NASA’s Goddard Center.
Tracking down carbon dioxide, methane and other gases with simultaneous determination of their concentrations at different altitudes is necessary, in particular, for research into global warming. The vast majority of scientists do not doubt the correlation between growing temperatures on the planet and the greenhouse effect, but so far it has been impossible to positively predict future changes in global warming.
A current lack of data on the distribution of greenhouse gases also compromises the forecasting and, consequently, the development of appropriate response measures. This is because in order to create a dense network of monitoring stations, many large, sophisticated and expensive spectrometers are needed.
The meter created by the Russian scientists is distinctive not only for its very high resolution, but also for its easy maintenance. The authors of the paper stress that their meter is far less susceptible to external disturbances compared with existing analogues. Its performance depends to a lesser extent on vibration, humidity and exposure to both low and high temperatures.
Alexander Rodin explained that the meter uses the heterodyne principle, known for over 100 years. The essence of the method could be best described as follows: a received signal is added to a reference signal to form an intermediate frequency signal. Generally, it does not matter whether it’s a radio wave or sunlight passing through the atmosphere, as is the case in the new meter.
The converted signal is much easier to process, namely to amplify and to filter. Moreover, when the frequency of the reference signal is sufficiently stable, extremely high sensitivity can be achieved. The only problem is that a signal of very high frequency, whether it is infrared or optical, is not so easy to add to the reference source – it must be very stable and at the same time emit radiation of high intensity.
The first heterodyne radios, operating at megahertz frequencies, were created in the early 20th century, becoming mass-produced toward the end of the Second World War; while in the terahertz sphere heterodyne devices appeared only recently. For near-infrared radiation, whose frequency is a few hundred times greater, the task of combining the signals appeared to be compounded by a number of technical difficulties.
Calculations showed that a more “touchy” device is needed for a heterodyne signal in the near infrared radiation spectrum. Even a shift of a few hundredths of a wavelength (i.e. a couple of dozen nanometers) could be critical, but eventually the researchers from MIPT and their colleagues from the Moscow-based General Physics Institute managed to create a heterodyne near-infrared detector, in which a key role was played by laser stabilization.
They used an optical system that directs a laser beam to two different points, one of them a special module for mixing it with sunlight passed through the atmosphere (i.e. the analyzed signal) and the other a cell with a pure sample of the gas to be identified.
Since the gas absorbs electromagnetic waves at a specific frequency, the brightness of the radiation going through the cell indicates how far the laser has deviated from the reference frequency. And this, in turn, makes it possible to adjust the frequency of the optical oscillator, i.e. laser (the word laser is an acronym of “light amplification by stimulated emission of radiation”).
New spectrum radiometers may be used at both stationary and mobile stations monitoring the atmosphere, according to the official site of the IVOLGA project, which is another abbreviation translated from Russian as “infrared heterodyne fiber analyzer.”
MIPT’s press service would like to thank Dr. Alexander Rodin for his generous help in writing this article.
Alexandra O. Borissova | Eurek Alert!
Connecting industrial outstations inexpensively and securely
14.07.2015 | Siemens AG
Management platform enables secure and simple remote access
29.06.2015 | Siemens AG
Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.
The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...
Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.
Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight
A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...
Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.
By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...
Argonne scientists used Mira to identify and improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity at the macroscale for the first time. Argonne Leadership Computing Facility (ALCF) researchers helped enable the groundbreaking simulations by overcoming a performance bottleneck that doubled the speed of the team's code.
While reviewing the simulation results of a promising new lubricant material, Argonne researcher Sanket Deshmukh stumbled upon a phenomenon that had never been...
23.07.2015 | Event News
10.07.2015 | Event News
25.06.2015 | Event News
30.07.2015 | Life Sciences
30.07.2015 | Trade Fair News
30.07.2015 | Awards Funding