An optical pulsar is a pulsar which can be detected in the visible spectrum. There are very few of these known: the Crab Pulsar was detected by stroboscopic techniques in 1969, shortly after its discovery in radio waves, at the Steward Observatory. The Vela Pulsar was detected in 1977 at the Anglo-Australian Observatory, and was the faintest star ever imaged at that time.
there are 13 recognized optical pulsars:Shearer, A.; Golden, A. (2022). "Why study pulsars optically?". Proceedings of the 270. WE-Heraeus Seminar on Neutron Stars, Pulsars, and Supernova Remnants. MPE Report 278. , arxiv
Name of pulsar Magnitude (B) Crab Pulsar (CM Tauri, PSR B0531+21) 16.5 Vela Pulsar 24 PSR B0540-69 (in the Large Magellanic Cloud) 23 PSR B0656+14 26 PSR B0633+17 (Geminga) 25.5 PSR B1509-58 (*) 25.7PSR J1023+003822PSR B1055−5224.9PSR B1929+1025.6PSR B1133+1628PSR B0950+0827.1PSR J0108−143126.4PSR J0437−471520.98±0.09 *Source included but not discussed in paper by source paper.
References
External links "A Pulsar Discovery: First Optical Pulsar." Moments of Discovery, American Institute of Physics, 2007 (Includes audio and teachers guides).