The Holographic Multi-wavelength Imaging Extinctiometer (HoloMIE): A new cloud probe for characterizing cloud particles and measuring spectral extinction

Airborne measurements of cloud particle size, shape, and optical properties such as extinction cross-section are critical for validating satellite remote sensing measurements and weather and climate models. To address the current and future needs of the scientific community making and using these measurements, we propose a multispectral single-particle holographic imaging system which offers several advantages over current techniques. Our approach exploits a novel property of holographic imaging to directly calculate extinction cross-section at multiple wavelengths. Single-particle holographic measurements avoid the computationally expensive processing required by other holographic instruments. The overall project objective is the development of a new instrument capable of imaging cloud droplets and ice crystals and performing spectrally resolved cloud extinction measurements. Here in Phase I, to de-risk the overall project, we propose the development and testing of a simplified breadboard optical system focusing on holographic measurements at a single wavelength with flowing particles to verify the performance of the instrument using several particle standards of known shapes, including those mimicking cloud particles in a laboratory setting.