Abstract: An apparatus includes a vacuum chamber, a first component, a second component that is movable relative to the first component, and a gas injector. The vacuum chamber includes a first vacuum zone and a second vacuum zone. The first component is disposed in the first vacuum zone at an interface with the second vacuum zone. The second component is disposed in the second vacuum zone at the interface and separated from the first component by a gap. The gas injector is configured to inject a buffer gas in the gap between the first component and the second component from at least one hole in at least one of the first component and the second component. The buffer gas provides a dynamic seal between the first vacuum zone and the second vacuum zone during movement of the second component relative to the first component.

Abstract: Systems, devices, and methods are described herein for performing digital holography to analyze dynamics of fluid flow. According to some aspects of this disclosure, a Digital Fresnel Reflection Holography (DFRH) system, which is arranged to utilize light backscattered from particles in a fluid chamber to create a hologram that may be processed to analyze characteristics of fluid flow. The DFRH system may utilize light reflected from an imaging window disposed between a light source and a sampling volume, to be analyzed as a reference wave, to form an interference pattern and resultant hologram. According to some aspects of this disclosure, the DFRH techniques may provide simple, cost-effective mechanisms with improved performance over other techniques for analyzing fluid flow using holography.

Abstract: Systems, devices, and methods are described herein for performing digital holography to analyze dynamics of fluid flow. According to some aspects of this disclosure, a Digital Fresnel Reflection Holography (DFRH) system, which is arranged to utilize light backscattered from particles in a fluid chamber to create a hologram that may be processed to analyze characteristics of fluid flow. The DFRH system may utilize light reflected from an imaging window disposed between a light source and a sampling volume, to be analyzed as a reference wave, to form an interference pattern and resultant hologram. According to some aspects of this disclosure, the DFRH techniques may provide simple, cost-effective mechanisms with improved performance over other techniques for analyzing fluid flow using holography.