A Laser Focus World article explains that radial velocity spectroscopy is an important method for finding exoplanets, and that advanced echelle gratings can deliver high-precision spectroscopic measurements to support exoplanet detection.
The spaceborne High-precision Main Greenhouse gas Imaging instrument (HMI) aboard the Pujiang-4 satellite began imaging on September 27 and downlinked its first data. The developer team led by Xiong Wei at the Anhui Institute of Optics and Fine Mechanics (AIOFM) performed a preliminary assessment and found that the payload's functions and performance met design requirements. HMI uses an information modulation technique combining spatial imaging and spectral interferometry, acquiring hyperspectral data in a 520 km orbit with a 30 km swath, spatial resolution better than 400 m, and spectral resolution better than 0.125 nm. From the first data, the team preliminarily estimated the methane emission rate of the Bogatyr open-pit mine in Kazakhstan at about 27.52±1.70 tons per hour.
Why we recommend it: The original article gives HMI's swath, spatial resolution and spectral resolution, and uses first data to estimate methane emissions from a mining area, showing the on-orbit performance of the combined spatial imaging and spectral interferometry approach
The article describes ultrashort pulse technology using nonlinear compression in multi-pass cells to achieve kilowatt average power and pulse energies at the tens-of-millijoule level.