Optical system for low-temperature scanning near-field optical microscope

Abstract

The invention discloses an optical system for a low-temperature scanning near-field optical microscope (SNOM), and belongs to the field of manufacturing of near-field optical instruments. The optical system for the low-temperature SNOM comprises a laser, a lighting optical fiber, a coarse approximation step motor, an optical focusing lens, a tuning fork, a needlepoint optical fiber, a spectrograph and a photomultiplier, wherein a moving component of the coarse approximation step motor is a quartz triangular prism; a through hole is formed in the center of the quartz triangular prism; the lighting optical fiber penetrates through the through hole; the optical focusing lens is fixed on the lower surface of the quartz triangular prism and comprises an upper lens and a lower lens which are optically coaxial; the needlepoint optical fiber and the tuning fork are fixed below the optical focusing lens; and the needlepoint optical fiber penetrates through the optical focusing lens, is then led out of a hole on the side wall of the lens barrel and is led into the spectrograph and the photomultiplier through the optical fiber. In the system, an open light path is not additionally increased,so that the adjustment of the light path in a vacuum cavity is simplified.

Description

technical field [0001] The invention belongs to the technical field of optical microscopes, in particular to a scanning near-field optical microscope optical system working in a low-temperature vacuum environment. Background technique [0002] Near-field optical microscopy (SNOM) exploits near-field interactions and can achieve a resolution of less than 100 nm, far superior to far-field microscopy limited by diffraction barriers. The idea of ​​using near-field optics for imaging was first proposed by Synge in 1928, who showed that the combination of illuminating an object through a subwavelength aperture and a detector very close to the sample allowed high resolution to be obtained through a non-diffraction-limited process. The conventional experimental instrument that turned the principle into reality was completed by Pohl et al. in 1984, so that the scanning near-field optical microscope was realized, and the optical diffraction limit was truly broken. Scanning near-field...

AI Technical Summary

Problems solved by technology

For the SNOM working in a low-temperature vacuum environment, since the scanning head is located inside the vacuum chamber, it is very difficult to set up and adjust the excitation or collection optical path outside the vacuum chamber due to the limitation of the numerical aperture of the lens and the working distance.

Images