4Pi confocal optical system with phase conjugation.

We propose a 4Pi confocal system that incorporates a phase-conjugate mirror into the system to solve the alignment problem and automatically correct the spherical aberration associated with the conventional 4Pi confocal system when observing a thick sample. The proposed system is experimentally verified by use of cerium-doped barium titanate crystal as the phase-conjugate mirror. The full width of the central peak is ~0.15 microm. We also theoretically verify the advantage of automatic correction of the spherical aberration by calculating the intensity distribution at the focal spot.

[1]  S Kawata,et al.  Three-dimensional optical memory with a photorefractive crystal. , 1995, Applied optics.

[2]  B Imbert,et al.  Near-infrared four-wave mixing with gain and self-starting oscillators with photorefractive GaAs. , 1989, Optics letters.

[3]  C. J. R. Sheppard,et al.  Improvement in axial resolution by interference confocal microscopy , 1991 .

[4]  W E Moerner,et al.  Net two-beam-coupling gain in a polymeric photorefractive material. , 1993, Optics letters.

[5]  S Kawata,et al.  Readout of three-dimensional optical memories. , 1996, Optics letters.

[6]  Stefan W. Hell,et al.  Fundamental improvement of resolution with a 4Pi-confocal fluorescence microscope using two-photon excitation , 1992 .

[7]  Satoshi Kawata,et al.  Three-dimensional confocal optical memory using photorefractive materials , 1994, Other Conferences.

[8]  Pekka Hänninen,et al.  Two-photon excitation 4Pi confocal microscope: enhanced axial resolution microscope for biological research , 1995 .

[9]  R. Frey,et al.  Collinear nearly degenerate four-wave mixing in intracavity amplifying media , 1986 .

[10]  W. Cathey,et al.  Superresolving phase conjugate scanning microscope. , 1990, Applied optics.

[11]  S. Hell,et al.  Properties of a 4Pi confocal fluorescence microscope , 1992 .

[12]  Colin J. R. Sheppard,et al.  Three-dimensional transfer functions in 4Pi confocal microscopes , 1994 .

[13]  Stefan W. Hell,et al.  Measurement of the 4Pi‐confocal point spread function proves 75 nm axial resolution , 1994 .