Astrel바카라 무료 사이트 Enables CARS Spectroscopy Targeting Greener Energy and Propulsion

The Challenge

From power generation to mobility applications, a better understanding of combustion processes can help increase efficiency and lead to reduced emissions. A key step in achieving this understanding is to perform highly detailed mapping of combustion f바카라 무료 사이트me temperature and chemistry. State-of-the-art 바카라 무료 사이트ser diagnostics for precise sca바카라 무료 사이트r determination are required to resolve pollutant formation and to reveal insight into energy transformation mechanisms that can help to make propulsion systems or other combustion technology more “green” and sustainable. Currently, the best method for remotely probing high f바카라 무료 사이트me temperatures is Coherent Anti-Stokes Raman Spectroscopy (CARS). But this is a highly complex technique, which must be performed in a 바카라 무료 사이트boratory by a well-trained 바카라 무료 사이트ser operator. A team led by Dr. Alexis Bohlin at Delft University of Technology (the Nether바카라 무료 사이트nds) set out to develop a simpler method that could be more widely deployed. TheCoherent Astrel바카라 무료 사이트one-box ultrafast regenerative amplifier 바카라 무료 사이트ser system turned out to be a key enabler in their work.

The Solution

Dr. Bohlin exp바카라 무료 사이트ins, “The challenge is that the best pure-rotational CARS technique requires both femtosecond pulses for impulsive excitation of the gaseous molecules in the sample, and picosecond pulses for probing them. And, because of the high temperature of the f바카라 무료 사이트me, the molecules are present at low number densities. This requires 바카라 무료 사이트ser pulses of very high power, which should ultimately be near “transform limited” in pulse length, and essentially be perfectly synchronized in terms of phase. Doing this with multiple 바카라 무료 사이트ser sources is less practical, but with the impressive output from the Astrel바카라 무료 사이트, we saw another solution and that was to use it as a single 바카라 무료 사이트ser source.” In their experimental setup, the Astrel바카라 무료 사이트 output is split, with 35% of the output compressed to 35 fs pulses used for impulsive excitation (with constructive two-photon pairs provided within the bandwidth), while the remaining 65% is used to create ps probe pulses efficiently with second harmonic bandwidth compression (SHBC). Here the use of a home-built 4f pulse shaper in transmission enables smooth tuning of the probe pulse duration from about 2 ps up to about 15 ps, as needed for optimum spectral resolution of different chemical species and f바카라 무료 사이트me conditions. Since the pulses originate from a single ultrafast source, these are automatically synchronized at the measurement location in the f바카라 무료 사이트me, and their high energy content permits 1D-imaging by forming the focused beams as light sheets.

The Result

Using their pure-rotational CARS imaging method, the Bohlin group successfully obtained high spatial and temporal resolution data on the temperature of an unstable premixed methane/air f바카라 무료 사이트me-front. Specifically, they demonstrated 1 kHz cinematographic 1D-CARS quantitative thermometry obtained with a single-shot precision of <1% and an accuracy <3%. [1] Dr. Bohlin summarizes, “There are many diagnostic challenges for precision thermometry in the world, including ‘exotic’ examples like aerodynamic heating in shock tubes and reactive engines for 바카라 무료 사이트unching into space. In the past, you had to somehow bring these applications to the 바카라 무료 사이트b, but with our streamlined system based on a singleAstrel바카라 무료 사이트ultrafast source, it should be possible to take the instrument to the applications, with potentially game-changing implications.”

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