Using lens aperture as a knife-edge in schlieren imaging
Abstract
A knife-edge is recognized as a critical component of a schlieren imaging system. This knife-edge serves as a cutoff element, which is required to achieve high sensitivity in schlieren imaging. This paper describes a method for transferring the role of the cutoff from an external discrete knife-edge component to the camera lens’s internal aperture. Thus, our approach completely removes an external knife-edge from the schlieren imaging system while maintaining the same sensitivity. We demonstrate this Lens Aperture as a Knife-Edge (LAKE) schlieren imaging in a single-mirror, near-coincident geometry that uses a reduced number of optomechanical elements. We show flow visualization results using LAKE schlieren that demonstrate easy switchability between schlieren versus shadowgraph imaging and horizontal versus vertical schlieren cutoff.
Fields of Study & Subjects
Computational Fluid Dynamics and Aerodynamics
Aerodynamics and Acoustics in Jet Flows
Flow Measurement and Analysis
Publication details
- Journal / source
- Applied Optics
- Publisher
- Optica Publishing Group
- Volume
- 65
- Issue
- 17
- Pages
- 5909–5909
- Publication date
- 26 May 2026
- Language
- EN