attoSNOM II
fiber based, low temperature scanning near-field optical microscope, interferometric sensor
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The attoSNOM II works by scanning a sub-wavelength sized probe in the near-field of a sample surface and has a novel for a variety of scanning near-field optical microscopy applications. The probe-sample distance control mechanism is based on an all fiber interferometer. It works by detecting the damping of the oscillating tip by lateral forces, the so-called ‘shear force‘, close to the surface.

One of the key features of this system is the ease of use due to the simple tip-sample distance control using the interferometric detection scheme and at the same time high optical efficiency due to the fiber based SNOM tips.

Tip-Sample Distance Control - The distance control is performed using the interferometric deflection detection scheme similar to the one applied in attoAFMs. The schematic drawing to the left describes the setup. A laser beam coupled into a single mode fiber (port 1) is used to illuminate a Fabry-Perot interferometer via a fiber coupler. At the end of the second arm (port 2), light is reflected at the end interface of the fiber. The rest of the light is transmitted and partially reflected at the SNOM fiber tip. Therefore, the tip interface and the fiber end face form a Fabry-Perot interferometer. A large part of the light reflected in this structure is coupled back into the optical fiber and detected with Detector 1. Detector 2 mounted at arm 3 can be used to monitor the intensity emitted by the laser (optional). Monitoring the intensity of the interference fringes allows to measure the tip vibration amplitude. The precision of the vibration amplitude measurement is 160 fm / Hz1/2.

Probes - This system is compatible with any fiber-based SNOM probe. In general, it is a glass-fiber tip which can be covered with an opaque metal layer. A clear aperture of sub-wavelength dimensions is located at the tip apex and records the optical signal.

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Detailed Specification Sheet

Complete System Solutions:
LTSYS	Complete system configurations for this product.