Near-field Optical Microscopy with Signal Processor Operable Imaging Device as Variable Area Photo Sensor

H. Muramatsu¹, and J. M. Kim²

1) Department of R&D, Seiko Instruments, Takatsuka-shinden, Matsudo, Chiba 270-2222 JAPAN
2) National Food Research Institute, Kannondai, Tsukuba, Ibaraki 305-8642 JAPAN

We have developed a signal processor that can operate an imaging device as a variable area photo sensor for our scanning near-field optical microscope (SNOM). The signal processor captures a video image signal of a CCD imaging device and converts an intensity of arbitrary area in the video image to numerical values and DC voltage signals, so that the CCD imaging device can be used as a photo detector of variable area and position. Using the DC voltage signal, near-field optical images are constructed in a scanning controller simultaneously with topographic images. The signal processor improves SNOM operation because careful adjustment of optical axes is not necessary in this system. Further combining with an image intensifier or spectrometer, the system can provide fluorescence or spectrum images. We show detail imaging results with this system in the conference.