Self-wavefront interference using transverse splitting holography

• Published in: Results in physics Vol. 52; p. 106839
• Main Authors: Bleahu, Andrei-ioan, Gopinath, Shivasubramanian, Kahro, Tauno, Hock Ng, Soon, Kukli, Kaupo, Tamm, Aile, Juodkazis, Saulius, Rosen, Joseph, Anand, Vijayakumar
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2023; Elsevier
• Subjects: Diffractive lens; Holography; Lucy-Richardson-Rosen algorithm; Photolithography; Self-interference; Super resolution; Holography; Self-interference; Lucy-Richardson-Rosen algorithm; Photolithography; Diffractive lens; Super resolution
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2023.106839

•A new incoherent imaging concept called Self-Wavefront Interference using Transverse Splitting Holography (SWITSH) has been proposed and demonstrated.•With SWITSH, it is possible to enhance the imaging resolution of low NA diffractive lenses beyond the diffraction limit.•In the proof-of-concept study, a resolution enhancement of ∼10 times has been demonstrated.•The proposed method is cost effective with a wide applicability enabling even a microdroplet or microlens for super resolution imaging applications.•This new concept can revolutionize coded aperture imaging technology replacing large NA coded apertures with smaller ones. Manufacturing diffractive lenses with a high Numerical Aperture (NA) is a challenging task due to limitations in lithography methods and the inverse relation between the width and the radius of the zones. With low-resolution lithography techniques such as photolithography, the zone width reaches the lithography limit within a short radius, resulting in low-NA diffractive lenses. With high-resolution electron beam lithography, it is possible to manufacture high-NA diffractive lenses by prolonged writing. However, in this case, the width of the outermost zones becomes subwavelength, inducing undesirable polarization effects. In this proof-of-concept study, a holography solution has been demonstrated to enhance the imaging resolution of low-NA diffractive lenses. The light from an object is partly modulated by the low-NA diffractive lens and interfered with the remaining unmodulated light outside the area of the diffractive lens. This self-interference hologram of the object is processed in the computer with the point spread hologram to reconstruct the object with a resolution corresponding to the NA of the image sensor. This new imaging technique is called Self-Wavefront Interference using Transverse Splitting Holography (SWITSH). A resolution enhancement of ∼10 times has been demonstrated using a low-NA diffractive lens and SWITSH compared to direct imaging with the same low-NA diffractive lens.