Eric J. Jumper's research while affiliated with University of Notre Dame and other places

... In order to better understand the underlying physics associated with these aero-optical aberrations, extensive lab-based [2][3][4][5]7,8,[14][15][16][17][18][19][20][21] and aircraft-based 6,[22][23][24][25][26][27][28][29][30] testing has been conducted in recent years. Although many foundational aero-optical experiments and analyses have been conducted, there is still much to learn about the coupling of fluidic properties and optical aberrations. ...

... Shack-Hartmann wavefront sensors are commonly used to measure the aero-optical distortions caused by the dependence of the air index of refraction on the gas density, as quantified by the optical path difference (OPD), in subsonic flow [28] atmospheric studies [29], as well as supersonic/hypersonic flows [30]. Since a Shack-Hartmann sensor measures the line-of-sight integral of fluctuations in the index of refraction caused by density inhomogeneity in the flow, it is used in this study to augment the qualitative schlieren imaging method in a horizontal plane, including a local flow velocity estimate, and provide an initial analysis of the flow perturbation pattern in the cross-flow direction, orthogonal to the pins-related shear layer. ...

... By leveraging the frozen turbulence hypothesis, measurement of the refractive index power spectral density (PSD) can be done optically through various methods such as wavefront sensing [6], differential seeing monitors [7], and optical phase noise [8][9][10]. The measurement of the optical phase noise has been of interest due to its use for determining the phase noise present in a communication system; however, it can also be used for sensing as the timing phase noise PSD, which is directly related to the refractive index PSD. ...

... In the aero-optical community, remarkable progress has been witnessed using wind tunnel experiments. Kemnetz et al. 30 tested the wavefront phase change induced by a Ma j (the subscript denotes jet) 0.07 injection emanating into an ambient Ma 1 0.6 flow, and employed a sub-harmonic disturbance for aero-optical control. From their observations, modifying the pressure-velocity term in strong Reynolds analogy (SRA) analysis was found to promote the accuracy of aero-optical estimation. ...

... Laser-based applications in the atmosphere or ocean, such as imaging [1], free-space communications [2], sensing [3], or directed energy [4], are subject to random density changes of the fluid due to turbulence. These random density changes vary the medium's refractive index, which affects light propagation by creating fluctuations in the optical path length and, consequently, the optical phase. ...

... A wide field of view (WFOV) camera with a 300 [mm] lens was used to locate the laboratory aircraft, and a narrow field of view (NFOV) camera with a 600 [mm] lens was used for tracking-either off the return signal or image features on the laboratory aircraft. Using the motorized beam divergence system, the divergence of the outgoing beam was changed by the user to sufficiently fill the acquisition window on the laboratory aircraft window regardless of the separation distance between aircraft [19,20]. ...

... The protrusion of the turret into the freestream flow creates a complicated turbulence environment, which can degrade the performance of these optical systems. [1][2][3][4][5][6][7][8][9][10] The optical-turbulence environment, which is caused by aerodynamic turbulence, is colloquially referred to as aero optics. [11][12][13] Laser beam propagation through shear layers has been one aero-optical environment of particular interest. ...

... The protrusion of the turret into the freestream flow creates a complicated turbulence environment, which can degrade the performance of these optical systems. [1][2][3][4][5][6][7][8][9][10] The optical-turbulence environment, which is caused by aerodynamic turbulence, is colloquially referred to as aero optics. [11][12][13] Laser beam propagation through shear layers has been one aero-optical environment of particular interest. ...

... In order to better understand the underlying physics associated with these aero-optical aberrations, extensive lab-based [2][3][4][5]7,8,[14][15][16][17][18][19][20][21] and aircraft-based 6,[22][23][24][25][26][27][28][29][30] testing has been conducted in recent years. Although many foundational aero-optical experiments and analyses have been conducted, there is still much to learn about the coupling of fluidic properties and optical aberrations. ...