All-optical spatial filtering with power limiting materials

Chandra S. Yelleswarapu, Pengfei Wu, Sri Rajasekhar Kothapalli, D. V.G.L.N. Rao, Brian R. Kimball, S. Siva Sankara Sai, R. Gowrishankar, S. Sivaramakrishnan

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


We demonstrated that a power limiting mechanism could potentially be used for self-adaptive, all-optical Fourier image processing. Reverse saturable absorbers like porphyrins are chosen due to their fluence dependent power limiting property, which triggers at relatively low intensities. At low input intensities, below the power-limiting threshold, the 4-f configuration will image the object onto the CCD camera without any spatial frequency filtering. As the input intensity is increased above the threshold level, dc and low spatial frequencies are blocked resulting in edge-enhanced images containing high spatial frequencies. The incident intensity sets the higher limit on the band of frequencies blocked. In addition, the use of the same experimental setup for both power limiting experiments and optical image processing demonstrates that in the case of any bright image bearing laser beam, the sensitive detectors are protected, by blocking the intense low spatial frequencies.

Original languageEnglish (US)
Pages (from-to)1451-1457
Number of pages7
JournalOptics Express
Issue number4
StatePublished - Feb 2006

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics


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